1 /*
2 * Copyright (c) 1996, 2024, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2024, Alibaba Group Holding Limited. All Rights Reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation. Oracle designates this
9 * particular file as subject to the "Classpath" exception as provided
10 * by Oracle in the LICENSE file that accompanied this code.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
23 * or visit www.oracle.com if you need additional information or have any
24 * questions.
25 */
26
27 package java.io;
28
29 import java.util.ArrayList;
30 import java.util.Arrays;
31 import java.util.List;
32 import java.util.Objects;
33 import java.util.StringJoiner;
34
35 import jdk.internal.util.ByteArray;
36 import jdk.internal.access.JavaLangAccess;
37 import jdk.internal.access.SharedSecrets;
38
39 import static java.io.ObjectInputStream.TRACE;
40
41 import static jdk.internal.util.ModifiedUtf.putChar;
42 import static jdk.internal.util.ModifiedUtf.utfLen;
43
44 /**
45 * An ObjectOutputStream writes primitive data types and graphs of Java objects
46 * to an OutputStream. The objects can be read (reconstituted) using an
47 * ObjectInputStream. Persistent storage of objects can be accomplished by
48 * using a file for the stream. If the stream is a network socket stream, the
49 * objects can be reconstituted on another host or in another process.
50 *
51 * <p>Only objects that support the java.io.Serializable interface can be
52 * written to streams. The class of each serializable object is encoded
53 * including the class name and signature of the class, the values of the
54 * object's fields and arrays, and the closure of any other objects referenced
55 * from the initial objects.
56 *
57 * <p>The method writeObject is used to write an object to the stream. Any
58 * object, including Strings and arrays, is written with writeObject. Multiple
59 * objects or primitives can be written to the stream. The objects must be
60 * read back from the corresponding ObjectInputstream with the same types and
61 * in the same order as they were written.
62 *
63 * <p>Primitive data types can also be written to the stream using the
64 * appropriate methods from DataOutput. Strings can also be written using the
65 * writeUTF method.
66 *
67 * <p>The default serialization mechanism for an object writes the class of the
68 * object, the class signature, and the values of all non-transient and
69 * non-static fields. References to other objects (except in transient or
70 * static fields) cause those objects to be written also. Multiple references
71 * to a single object are encoded using a reference sharing mechanism so that
72 * graphs of objects can be restored to the same shape as when the original was
73 * written.
74 *
75 * <p>For example to write an object that can be read by the example in
76 * {@link ObjectInputStream}:
77 * {@snippet lang="java":
78 * try (FileOutputStream fos = new FileOutputStream("t.tmp");
79 * ObjectOutputStream oos = new ObjectOutputStream(fos)) {
80 * oos.writeObject("Today");
81 * oos.writeObject(LocalDateTime.now());
82 * } catch (Exception ex) {
83 * // handle exception
84 * }
85 * }
86 *
87 * <p>Serializable classes that require special handling during the
88 * serialization and deserialization process should implement methods
89 * with the following signatures:
90 *
91 * {@snippet lang="java":
92 * private void readObject(java.io.ObjectInputStream stream)
93 * throws IOException, ClassNotFoundException;
94 * private void writeObject(java.io.ObjectOutputStream stream)
95 * throws IOException;
96 * private void readObjectNoData()
97 * throws ObjectStreamException;
98 * }
99 *
100 * <p>The method name, modifiers, return type, and number and type of
101 * parameters must match exactly for the method to be used by
102 * serialization or deserialization. The methods should only be
103 * declared to throw checked exceptions consistent with these
104 * signatures.
105 *
106 * <p>The writeObject method is responsible for writing the state of the object
107 * for its particular class so that the corresponding readObject method can
108 * restore it. The method does not need to concern itself with the state
109 * belonging to the object's superclasses or subclasses. State is saved by
110 * writing the individual fields to the ObjectOutputStream using the
111 * writeObject method or by using the methods for primitive data types
112 * supported by DataOutput.
113 *
114 * <p>Serialization does not write out the fields of any object that does not
115 * implement the java.io.Serializable interface. Subclasses of Objects that
116 * are not serializable can be serializable. In this case the non-serializable
117 * class must have a no-arg constructor to allow its fields to be initialized.
118 * In this case it is the responsibility of the subclass to save and restore
119 * the state of the non-serializable class. It is frequently the case that the
120 * fields of that class are accessible (public, package, or protected) or that
121 * there are get and set methods that can be used to restore the state.
122 *
123 * <p>Serialization of an object can be prevented by implementing writeObject
124 * and readObject methods that throw the NotSerializableException. The
125 * exception will be caught by the ObjectOutputStream and abort the
126 * serialization process.
127 *
128 * <p>Implementing the Externalizable interface allows the object to assume
129 * complete control over the contents and format of the object's serialized
130 * form. The methods of the Externalizable interface, writeExternal and
131 * readExternal, are called to save and restore the objects state. When
132 * implemented by a class they can write and read their own state using all of
133 * the methods of ObjectOutput and ObjectInput. It is the responsibility of
134 * the objects to handle any versioning that occurs.
135 * Value classes implementing {@link Externalizable} cannot be serialized
136 * or deserialized, the value object is immutable and the state cannot be restored.
137 * Use {@link Serializable} {@code writeReplace} to delegate to another serializable
138 * object such as a record.
139 *
140 * Value objects cannot be {@code java.io.Externalizable}.
141 *
142 * <p>Enum constants are serialized differently than ordinary serializable or
143 * externalizable objects. The serialized form of an enum constant consists
144 * solely of its name; field values of the constant are not transmitted. To
145 * serialize an enum constant, ObjectOutputStream writes the string returned by
146 * the constant's name method. Like other serializable or externalizable
147 * objects, enum constants can function as the targets of back references
148 * appearing subsequently in the serialization stream. The process by which
149 * enum constants are serialized cannot be customized; any class-specific
150 * writeObject and writeReplace methods defined by enum types are ignored
151 * during serialization. Similarly, any serialPersistentFields or
152 * serialVersionUID field declarations are also ignored--all enum types have a
153 * fixed serialVersionUID of 0L.
154 *
155 * <p>Primitive data, excluding serializable fields and externalizable data, is
156 * written to the ObjectOutputStream in block-data records. A block data record
157 * is composed of a header and data. The block data header consists of a marker
158 * and the number of bytes to follow the header. Consecutive primitive data
159 * writes are merged into one block-data record. The blocking factor used for
160 * a block-data record will be 1024 bytes. Each block-data record will be
161 * filled up to 1024 bytes, or be written whenever there is a termination of
162 * block-data mode. Calls to the ObjectOutputStream methods writeObject,
163 * defaultWriteObject and writeFields initially terminate any existing
164 * block-data record.
165 *
166 * <a id="record-serialization"></a>
167 * <p>Records are serialized differently than ordinary serializable or externalizable
168 * objects, see <a href="ObjectInputStream.html#record-serialization">record serialization</a>.
169 *
170 * <a id="valueclass-serialization"></a>
171 * <p>Value classes are {@linkplain Serializable} through the use of the serialization proxy pattern.
172 * The serialization protocol does not support a standard serialized form for value classes.
173 * The value class delegates to a serialization proxy by supplying an alternate
174 * record or object to be serialized instead of the value class.
175 * When the proxy is deserialized it re-constructs the value object and returns the value object.
176 * For example,
177 * {@snippet lang="java" :
178 * value class ZipCode implements Serializable { // @highlight substring="value class"
179 * private static final long serialVersionUID = 1L;
180 * private int zipCode;
181 * public ZipCode(int zip) { this.zipCode = zip; }
182 * public int zipCode() { return zipCode; }
183 *
184 * public Object writeReplace() { // @highlight substring="writeReplace"
185 * return new ZipCodeProxy(zipCode);
186 * }
187 *
188 * private record ZipCodeProxy(int zipCode) implements Serializable {
189 * public Object readResolve() { // @highlight substring="readResolve"
190 * return new ZipCode(zipCode);
191 * }
192 * }
193 * }
194 * }
195 *
196 * @spec serialization/index.html Java Object Serialization Specification
197 * @author Mike Warres
198 * @author Roger Riggs
199 * @see java.io.DataOutput
200 * @see java.io.ObjectInputStream
201 * @see java.io.Serializable
202 * @see java.io.Externalizable
203 * @see <a href="{@docRoot}/../specs/serialization/output.html">
204 * <cite>Java Object Serialization Specification,</cite> Section 2, "Object Output Classes"</a>
205 * @since 1.1
206 */
207 public class ObjectOutputStream
208 extends OutputStream implements ObjectOutput, ObjectStreamConstants
209 {
210 private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
211
212 private static class Caches {
213 /** cache of subclass security audit results */
214 static final ClassValue<Boolean> subclassAudits =
215 new ClassValue<>() {
216 @Override
217 protected Boolean computeValue(Class<?> type) {
218 return auditSubclass(type);
219 }
220 };
221 }
222
223 /** filter stream for handling block data conversion */
224 private final BlockDataOutputStream bout;
225 /** obj -> wire handle map */
226 private final HandleTable handles;
227 /** obj -> replacement obj map */
228 private final ReplaceTable subs;
229 /** stream protocol version */
230 private int protocol = PROTOCOL_VERSION_2;
231 /** recursion depth */
232 private int depth;
233
234 /** buffer for writing primitive field values */
235 private byte[] primVals;
236
237 /** if true, invoke writeObjectOverride() instead of writeObject() */
238 private final boolean enableOverride;
239 /** if true, invoke replaceObject() */
240 private boolean enableReplace;
241
242 // values below valid only during upcalls to writeObject()/writeExternal()
243 /**
244 * Context during upcalls to class-defined writeObject methods; holds
245 * object currently being serialized and descriptor for current class.
246 * Null when not during writeObject upcall.
247 */
248 private SerialCallbackContext curContext;
249 /** current PutField object */
250 private PutFieldImpl curPut;
251
252 /** custom storage for debug trace info */
253 private final DebugTraceInfoStack debugInfoStack;
254
255 /**
256 * value of "sun.io.serialization.extendedDebugInfo" property,
257 * as true or false for extended information about exception's place
258 */
259 private static final boolean extendedDebugInfo =
260 Boolean.getBoolean("sun.io.serialization.extendedDebugInfo");
261
262 /**
263 * Creates an ObjectOutputStream that writes to the specified OutputStream.
264 * This constructor writes the serialization stream header to the
265 * underlying stream; callers may wish to flush the stream immediately to
266 * ensure that constructors for receiving ObjectInputStreams will not block
267 * when reading the header.
268 *
269 * @param out output stream to write to
270 * @throws IOException if an I/O error occurs while writing stream header
271 * @throws NullPointerException if {@code out} is {@code null}
272 * @since 1.4
273 * @see ObjectOutputStream#ObjectOutputStream()
274 * @see ObjectOutputStream#putFields()
275 * @see ObjectInputStream#ObjectInputStream(InputStream)
276 */
277 @SuppressWarnings("this-escape")
278 public ObjectOutputStream(OutputStream out) throws IOException {
279 bout = new BlockDataOutputStream(out);
280 handles = new HandleTable(10, (float) 3.00);
281 subs = new ReplaceTable(10, (float) 3.00);
282 enableOverride = false;
283 writeStreamHeader();
284 bout.setBlockDataMode(true);
285 if (extendedDebugInfo) {
286 debugInfoStack = new DebugTraceInfoStack();
287 } else {
288 debugInfoStack = null;
289 }
290 }
291
292 /**
293 * Provide a way for subclasses that are completely reimplementing
294 * ObjectOutputStream to not have to allocate private data just used by
295 * this implementation of ObjectOutputStream.
296 *
297 * @throws IOException if an I/O error occurs while creating this stream
298 */
299 protected ObjectOutputStream() throws IOException {
300 bout = null;
301 handles = null;
302 subs = null;
303 enableOverride = true;
304 debugInfoStack = null;
305 }
306
307 /**
308 * Specify stream protocol version to use when writing the stream.
309 *
310 * <p>This routine provides a hook to enable the current version of
311 * Serialization to write in a format that is backwards compatible to a
312 * previous version of the stream format.
313 *
314 * <p>Every effort will be made to avoid introducing additional
315 * backwards incompatibilities; however, sometimes there is no
316 * other alternative.
317 *
318 * @param version use ProtocolVersion from java.io.ObjectStreamConstants.
319 * @throws IllegalStateException if called after any objects
320 * have been serialized.
321 * @throws IllegalArgumentException if invalid version is passed in.
322 * @throws IOException if I/O errors occur
323 * @see java.io.ObjectStreamConstants#PROTOCOL_VERSION_1
324 * @see java.io.ObjectStreamConstants#PROTOCOL_VERSION_2
325 * @since 1.2
326 */
327 public void useProtocolVersion(int version) throws IOException {
328 if (handles.size() != 0) {
329 // REMIND: implement better check for pristine stream?
330 throw new IllegalStateException("stream non-empty");
331 }
332 switch (version) {
333 case PROTOCOL_VERSION_1:
334 case PROTOCOL_VERSION_2:
335 protocol = version;
336 break;
337
338 default:
339 throw new IllegalArgumentException(
340 "unknown version: " + version);
341 }
342 }
343
344 /**
345 * Write the specified object to the ObjectOutputStream. The class of the
346 * object, the signature of the class, and the values of the non-transient
347 * and non-static fields of the class and all of its supertypes are
348 * written. Default serialization for a class can be overridden using the
349 * writeObject and the readObject methods. Objects referenced by this
350 * object are written transitively so that a complete equivalent graph of
351 * objects can be reconstructed by an ObjectInputStream.
352 *
353 * <p>Serialization and deserialization of value classes is described in
354 * {@linkplain ObjectOutputStream##valueclass-serialization value class serialization}.
355 *
356 * <p>Exceptions are thrown for problems with the OutputStream and for
357 * classes that should not be serialized. All exceptions are fatal to the
358 * OutputStream, which is left in an indeterminate state, and it is up to
359 * the caller to ignore or recover the stream state.
360 *
361 * @throws InvalidClassException Something is wrong with a class used by
362 * serialization.
363 * @throws NotSerializableException Some object to be serialized does not
364 * implement the java.io.Serializable interface.
365 * @throws IOException Any exception thrown by the underlying
366 * OutputStream.
367 */
368 public final void writeObject(Object obj) throws IOException {
369 if (enableOverride) {
370 writeObjectOverride(obj);
371 return;
372 }
373 try {
374 writeObject0(obj, false);
375 } catch (IOException ex) {
376 if (depth == 0) {
377 writeFatalException(ex);
378 }
379 throw ex;
380 }
381 }
382
383 /**
384 * Method used by subclasses to override the default writeObject method.
385 * This method is called by trusted subclasses of ObjectOutputStream that
386 * constructed ObjectOutputStream using the protected no-arg constructor.
387 * The subclass is expected to provide an override method with the modifier
388 * "final".
389 *
390 * @param obj object to be written to the underlying stream
391 * @throws IOException if there are I/O errors while writing to the
392 * underlying stream
393 * @see #ObjectOutputStream()
394 * @see #writeObject(Object)
395 * @since 1.2
396 */
397 protected void writeObjectOverride(Object obj) throws IOException {
398 }
399
400 /**
401 * Writes an "unshared" object to the ObjectOutputStream. This method is
402 * identical to writeObject, except that it always writes the given object
403 * as a new, unique object in the stream (as opposed to a back-reference
404 * pointing to a previously serialized instance). Specifically:
405 * <ul>
406 * <li>An object written via writeUnshared is always serialized in the
407 * same manner as a newly appearing object (an object that has not
408 * been written to the stream yet), regardless of whether or not the
409 * object has been written previously.
410 *
411 * <li>If writeObject is used to write an object that has been previously
412 * written with writeUnshared, the previous writeUnshared operation
413 * is treated as if it were a write of a separate object. In other
414 * words, ObjectOutputStream will never generate back-references to
415 * object data written by calls to writeUnshared.
416 * </ul>
417 * While writing an object via writeUnshared does not in itself guarantee a
418 * unique reference to the object when it is deserialized, it allows a
419 * single object to be defined multiple times in a stream, so that multiple
420 * calls to readUnshared by the receiver will not conflict. Note that the
421 * rules described above only apply to the base-level object written with
422 * writeUnshared, and not to any transitively referenced sub-objects in the
423 * object graph to be serialized.
424 *
425 * @param obj object to write to stream
426 * @throws NotSerializableException if an object in the graph to be
427 * serialized does not implement the Serializable interface
428 * @throws InvalidClassException if a problem exists with the class of an
429 * object to be serialized
430 * @throws IOException if an I/O error occurs during serialization
431 * @since 1.4
432 */
433 public void writeUnshared(Object obj) throws IOException {
434 try {
435 writeObject0(obj, true);
436 } catch (IOException ex) {
437 if (depth == 0) {
438 writeFatalException(ex);
439 }
440 throw ex;
441 }
442 }
443
444 /**
445 * Write the non-static and non-transient fields of the current class to
446 * this stream. This may only be called from the writeObject method of the
447 * class being serialized. It will throw the NotActiveException if it is
448 * called otherwise.
449 *
450 * @throws IOException if I/O errors occur while writing to the underlying
451 * {@code OutputStream}
452 */
453 public void defaultWriteObject() throws IOException {
454 SerialCallbackContext ctx = curContext;
455 if (ctx == null) {
456 throw new NotActiveException("not in call to writeObject");
457 }
458 Object curObj = ctx.getObj();
459 ObjectStreamClass curDesc = ctx.getDesc();
460 bout.setBlockDataMode(false);
461 defaultWriteFields(curObj, curDesc);
462 bout.setBlockDataMode(true);
463 }
464
465 /**
466 * Retrieve the object used to buffer persistent fields to be written to
467 * the stream. The fields will be written to the stream when writeFields
468 * method is called.
469 *
470 * @return an instance of the class Putfield that holds the serializable
471 * fields
472 * @throws IOException if I/O errors occur
473 * @since 1.2
474 */
475 public ObjectOutputStream.PutField putFields() throws IOException {
476 if (curPut == null) {
477 SerialCallbackContext ctx = curContext;
478 if (ctx == null) {
479 throw new NotActiveException("not in call to writeObject");
480 }
481 ctx.checkAndSetUsed();
482 ObjectStreamClass curDesc = ctx.getDesc();
483 curPut = new PutFieldImpl(curDesc);
484 }
485 return curPut;
486 }
487
488 /**
489 * Write the buffered fields to the stream.
490 *
491 * @throws IOException if I/O errors occur while writing to the underlying
492 * stream
493 * @throws NotActiveException Called when a classes writeObject method was
494 * not called to write the state of the object.
495 * @since 1.2
496 */
497 public void writeFields() throws IOException {
498 if (curPut == null) {
499 throw new NotActiveException("no current PutField object");
500 }
501 bout.setBlockDataMode(false);
502 curPut.writeFields();
503 bout.setBlockDataMode(true);
504 }
505
506 /**
507 * Reset will disregard the state of any objects already written to the
508 * stream. The state is reset to be the same as a new ObjectOutputStream.
509 * The current point in the stream is marked as reset so the corresponding
510 * ObjectInputStream will be reset at the same point. Objects previously
511 * written to the stream will not be referred to as already being in the
512 * stream. They will be written to the stream again.
513 *
514 * @throws IOException if reset() is invoked while serializing an object.
515 */
516 public void reset() throws IOException {
517 if (depth != 0) {
518 throw new IOException("stream active");
519 }
520 bout.setBlockDataMode(false);
521 bout.writeByte(TC_RESET);
522 clear();
523 bout.setBlockDataMode(true);
524 }
525
526 /**
527 * Subclasses may implement this method to allow class data to be stored in
528 * the stream. By default this method does nothing. The corresponding
529 * method in ObjectInputStream is resolveClass. This method is called
530 * exactly once for each unique class in the stream. The class name and
531 * signature will have already been written to the stream. This method may
532 * make free use of the ObjectOutputStream to save any representation of
533 * the class it deems suitable (for example, the bytes of the class file).
534 * The resolveClass method in the corresponding subclass of
535 * ObjectInputStream must read and use any data or objects written by
536 * annotateClass.
537 *
538 * @param cl the class to annotate custom data for
539 * @throws IOException Any exception thrown by the underlying
540 * OutputStream.
541 */
542 protected void annotateClass(Class<?> cl) throws IOException {
543 }
544
545 /**
546 * Subclasses may implement this method to store custom data in the stream
547 * along with descriptors for dynamic proxy classes.
548 *
549 * <p>This method is called exactly once for each unique proxy class
550 * descriptor in the stream. The default implementation of this method in
551 * {@code ObjectOutputStream} does nothing.
552 *
553 * <p>The corresponding method in {@code ObjectInputStream} is
554 * {@code resolveProxyClass}. For a given subclass of
555 * {@code ObjectOutputStream} that overrides this method, the
556 * {@code resolveProxyClass} method in the corresponding subclass of
557 * {@code ObjectInputStream} must read any data or objects written by
558 * {@code annotateProxyClass}.
559 *
560 * @param cl the proxy class to annotate custom data for
561 * @throws IOException any exception thrown by the underlying
562 * {@code OutputStream}
563 * @see ObjectInputStream#resolveProxyClass(String[])
564 * @since 1.3
565 */
566 protected void annotateProxyClass(Class<?> cl) throws IOException {
567 }
568
569 /**
570 * This method will allow trusted subclasses of ObjectOutputStream to
571 * substitute one object for another during serialization. Replacing
572 * objects is disabled until enableReplaceObject is called. The
573 * enableReplaceObject method checks that the stream requesting to do
574 * replacement can be trusted. The first occurrence of each object written
575 * into the serialization stream is passed to replaceObject. Subsequent
576 * references to the object are replaced by the object returned by the
577 * original call to replaceObject. To ensure that the private state of
578 * objects is not unintentionally exposed, only trusted streams may use
579 * replaceObject.
580 *
581 * <p>The ObjectOutputStream.writeObject method takes a parameter of type
582 * Object (as opposed to type Serializable) to allow for cases where
583 * non-serializable objects are replaced by serializable ones.
584 *
585 * <p>When a subclass is replacing objects it must ensure that either a
586 * complementary substitution must be made during deserialization or that
587 * the substituted object is compatible with every field where the
588 * reference will be stored. Objects whose type is not a subclass of the
589 * type of the field or array element abort the serialization by raising an
590 * exception and the object is not be stored.
591 *
592 * <p>This method is called only once when each object is first
593 * encountered. All subsequent references to the object will be redirected
594 * to the new object. This method should return the object to be
595 * substituted or the original object.
596 *
597 * <p>Null can be returned as the object to be substituted, but may cause
598 * {@link NullPointerException} in classes that contain references to the
599 * original object since they may be expecting an object instead of
600 * null.
601 *
602 * @param obj the object to be replaced
603 * @return the alternate object that replaced the specified one
604 * @throws IOException Any exception thrown by the underlying
605 * OutputStream.
606 */
607 protected Object replaceObject(Object obj) throws IOException {
608 return obj;
609 }
610
611 /**
612 * Enables the stream to do replacement of objects written to the stream. When
613 * enabled, the {@link #replaceObject} method is called for every object being
614 * serialized.
615 *
616 * @param enable true for enabling use of {@code replaceObject} for
617 * every object being serialized
618 * @return the previous setting before this method was invoked
619 */
620 protected boolean enableReplaceObject(boolean enable) {
621 if (enable == enableReplace) {
622 return enable;
623 }
624 enableReplace = enable;
625 return !enableReplace;
626 }
627
628 /**
629 * The writeStreamHeader method is provided so subclasses can append or
630 * prepend their own header to the stream. It writes the magic number and
631 * version to the stream.
632 *
633 * @throws IOException if I/O errors occur while writing to the underlying
634 * stream
635 */
636 protected void writeStreamHeader() throws IOException {
637 bout.writeShort(STREAM_MAGIC);
638 bout.writeShort(STREAM_VERSION);
639 }
640
641 /**
642 * Write the specified class descriptor to the ObjectOutputStream. Class
643 * descriptors are used to identify the classes of objects written to the
644 * stream. Subclasses of ObjectOutputStream may override this method to
645 * customize the way in which class descriptors are written to the
646 * serialization stream. The corresponding method in ObjectInputStream,
647 * {@link ObjectInputStream#readClassDescriptor readClassDescriptor}, should then be
648 * overridden to reconstitute the class descriptor from its custom stream representation.
649 * By default, this method writes class descriptors according to the format
650 * defined in the <a href="{@docRoot}/../specs/serialization/index.html">
651 * <cite>Java Object Serialization Specification</cite></a>.
652 *
653 * <p>Note that this method will only be called if the ObjectOutputStream
654 * is not using the old serialization stream format (set by calling
655 * ObjectOutputStream's {@code useProtocolVersion} method). If this
656 * serialization stream is using the old format
657 * ({@code PROTOCOL_VERSION_1}), the class descriptor will be written
658 * internally in a manner that cannot be overridden or customized.
659 *
660 * @param desc class descriptor to write to the stream
661 * @throws IOException If an I/O error has occurred.
662 * @spec serialization/index.html Java Object Serialization Specification
663 * @see java.io.ObjectInputStream#readClassDescriptor()
664 * @see #useProtocolVersion(int)
665 * @see java.io.ObjectStreamConstants#PROTOCOL_VERSION_1
666 * @since 1.3
667 */
668 protected void writeClassDescriptor(ObjectStreamClass desc)
669 throws IOException
670 {
671 desc.writeNonProxy(this);
672 }
673
674 /**
675 * Writes a byte. This method will block until the byte is actually
676 * written.
677 *
678 * @param val the byte to be written to the stream
679 * @throws IOException If an I/O error has occurred.
680 */
681 @Override
682 public void write(int val) throws IOException {
683 bout.write(val);
684 }
685
686 /**
687 * Writes an array of bytes. This method will block until the bytes are
688 * actually written.
689 *
690 * @param buf the data to be written
691 * @throws IOException If an I/O error has occurred.
692 */
693 @Override
694 public void write(byte[] buf) throws IOException {
695 bout.write(buf, 0, buf.length, false);
696 }
697
698 /**
699 * Writes a sub array of bytes.
700 *
701 * @param buf the data to be written
702 * @param off the start offset in the data
703 * @param len the number of bytes that are written
704 * @throws IOException {@inheritDoc}
705 * @throws IndexOutOfBoundsException {@inheritDoc}
706 */
707 @Override
708 public void write(byte[] buf, int off, int len) throws IOException {
709 if (buf == null) {
710 throw new NullPointerException();
711 }
712 Objects.checkFromIndexSize(off, len, buf.length);
713 bout.write(buf, off, len, false);
714 }
715
716 /**
717 * Flushes the stream. This will write any buffered output bytes and flush
718 * through to the underlying stream.
719 *
720 * @throws IOException {@inheritDoc}
721 */
722 @Override
723 public void flush() throws IOException {
724 bout.flush();
725 }
726
727 /**
728 * Drain any buffered data in ObjectOutputStream. Similar to flush but
729 * does not propagate the flush to the underlying stream.
730 *
731 * @throws IOException if I/O errors occur while writing to the underlying
732 * stream
733 */
734 protected void drain() throws IOException {
735 bout.drain();
736 }
737
738 /**
739 * Closes the stream. This method must be called to release any resources
740 * associated with the stream.
741 *
742 * @throws IOException If an I/O error has occurred.
743 */
744 @Override
745 public void close() throws IOException {
746 flush();
747 clear();
748 bout.close();
749 }
750
751 /**
752 * Writes a boolean.
753 *
754 * @param val the boolean to be written
755 * @throws IOException if I/O errors occur while writing to the underlying
756 * stream
757 */
758 public void writeBoolean(boolean val) throws IOException {
759 bout.writeBoolean(val);
760 }
761
762 /**
763 * Writes an 8-bit byte.
764 *
765 * @param val the byte value to be written
766 * @throws IOException if I/O errors occur while writing to the underlying
767 * stream
768 */
769 public void writeByte(int val) throws IOException {
770 bout.writeByte(val);
771 }
772
773 /**
774 * Writes a 16-bit short.
775 *
776 * @param val the short value to be written
777 * @throws IOException if I/O errors occur while writing to the underlying
778 * stream
779 */
780 public void writeShort(int val) throws IOException {
781 bout.writeShort(val);
782 }
783
784 /**
785 * Writes a 16-bit char.
786 *
787 * @param val the char value to be written
788 * @throws IOException if I/O errors occur while writing to the underlying
789 * stream
790 */
791 public void writeChar(int val) throws IOException {
792 bout.writeChar(val);
793 }
794
795 /**
796 * Writes a 32-bit int.
797 *
798 * @param val the integer value to be written
799 * @throws IOException if I/O errors occur while writing to the underlying
800 * stream
801 */
802 public void writeInt(int val) throws IOException {
803 bout.writeInt(val);
804 }
805
806 /**
807 * Writes a 64-bit long.
808 *
809 * @param val the long value to be written
810 * @throws IOException if I/O errors occur while writing to the underlying
811 * stream
812 */
813 public void writeLong(long val) throws IOException {
814 bout.writeLong(val);
815 }
816
817 /**
818 * Writes a 32-bit float.
819 *
820 * @param val the float value to be written
821 * @throws IOException if I/O errors occur while writing to the underlying
822 * stream
823 */
824 public void writeFloat(float val) throws IOException {
825 bout.writeFloat(val);
826 }
827
828 /**
829 * Writes a 64-bit double.
830 *
831 * @param val the double value to be written
832 * @throws IOException if I/O errors occur while writing to the underlying
833 * stream
834 */
835 public void writeDouble(double val) throws IOException {
836 bout.writeDouble(val);
837 }
838
839 /**
840 * Writes a String as a sequence of bytes.
841 *
842 * @param str the String of bytes to be written
843 * @throws IOException if I/O errors occur while writing to the underlying
844 * stream
845 */
846 public void writeBytes(String str) throws IOException {
847 bout.writeBytes(str);
848 }
849
850 /**
851 * Writes a String as a sequence of chars.
852 *
853 * @param str the String of chars to be written
854 * @throws IOException if I/O errors occur while writing to the underlying
855 * stream
856 */
857 public void writeChars(String str) throws IOException {
858 bout.writeChars(str);
859 }
860
861 /**
862 * Primitive data write of this String in
863 * <a href="DataInput.html#modified-utf-8">modified UTF-8</a>
864 * format. Note that there is a
865 * significant difference between writing a String into the stream as
866 * primitive data or as an Object. A String instance written by writeObject
867 * is written into the stream as a String initially. Future writeObject()
868 * calls write references to the string into the stream.
869 *
870 * @param str the String to be written
871 * @throws IOException if I/O errors occur while writing to the underlying
872 * stream
873 */
874 public void writeUTF(String str) throws IOException {
875 bout.writeUTFInternal(str, false);
876 }
877
878 /**
879 * Provide programmatic access to the persistent fields to be written
880 * to ObjectOutput.
881 *
882 * @since 1.2
883 */
884 public abstract static class PutField {
885 /**
886 * Constructor for subclasses to call.
887 */
888 public PutField() {}
889
890 /**
891 * Put the value of the named boolean field into the persistent field.
892 *
893 * @param name the name of the serializable field
894 * @param val the value to assign to the field
895 * @throws IllegalArgumentException if {@code name} does not
896 * match the name of a serializable field for the class whose fields
897 * are being written, or if the type of the named field is not
898 * {@code boolean}
899 */
900 public abstract void put(String name, boolean val);
901
902 /**
903 * Put the value of the named byte field into the persistent field.
904 *
905 * @param name the name of the serializable field
906 * @param val the value to assign to the field
907 * @throws IllegalArgumentException if {@code name} does not
908 * match the name of a serializable field for the class whose fields
909 * are being written, or if the type of the named field is not
910 * {@code byte}
911 */
912 public abstract void put(String name, byte val);
913
914 /**
915 * Put the value of the named char field into the persistent field.
916 *
917 * @param name the name of the serializable field
918 * @param val the value to assign to the field
919 * @throws IllegalArgumentException if {@code name} does not
920 * match the name of a serializable field for the class whose fields
921 * are being written, or if the type of the named field is not
922 * {@code char}
923 */
924 public abstract void put(String name, char val);
925
926 /**
927 * Put the value of the named short field into the persistent field.
928 *
929 * @param name the name of the serializable field
930 * @param val the value to assign to the field
931 * @throws IllegalArgumentException if {@code name} does not
932 * match the name of a serializable field for the class whose fields
933 * are being written, or if the type of the named field is not
934 * {@code short}
935 */
936 public abstract void put(String name, short val);
937
938 /**
939 * Put the value of the named int field into the persistent field.
940 *
941 * @param name the name of the serializable field
942 * @param val the value to assign to the field
943 * @throws IllegalArgumentException if {@code name} does not
944 * match the name of a serializable field for the class whose fields
945 * are being written, or if the type of the named field is not
946 * {@code int}
947 */
948 public abstract void put(String name, int val);
949
950 /**
951 * Put the value of the named long field into the persistent field.
952 *
953 * @param name the name of the serializable field
954 * @param val the value to assign to the field
955 * @throws IllegalArgumentException if {@code name} does not
956 * match the name of a serializable field for the class whose fields
957 * are being written, or if the type of the named field is not
958 * {@code long}
959 */
960 public abstract void put(String name, long val);
961
962 /**
963 * Put the value of the named float field into the persistent field.
964 *
965 * @param name the name of the serializable field
966 * @param val the value to assign to the field
967 * @throws IllegalArgumentException if {@code name} does not
968 * match the name of a serializable field for the class whose fields
969 * are being written, or if the type of the named field is not
970 * {@code float}
971 */
972 public abstract void put(String name, float val);
973
974 /**
975 * Put the value of the named double field into the persistent field.
976 *
977 * @param name the name of the serializable field
978 * @param val the value to assign to the field
979 * @throws IllegalArgumentException if {@code name} does not
980 * match the name of a serializable field for the class whose fields
981 * are being written, or if the type of the named field is not
982 * {@code double}
983 */
984 public abstract void put(String name, double val);
985
986 /**
987 * Put the value of the named Object field into the persistent field.
988 *
989 * @param name the name of the serializable field
990 * @param val the value to assign to the field
991 * (which may be {@code null})
992 * @throws IllegalArgumentException if {@code name} does not
993 * match the name of a serializable field for the class whose fields
994 * are being written, or if the type of the named field is not a
995 * reference type
996 */
997 public abstract void put(String name, Object val);
998
999 /**
1000 * Write the data and fields to the specified ObjectOutput stream,
1001 * which must be the same stream that produced this
1002 * {@code PutField} object.
1003 *
1004 * @param out the stream to write the data and fields to
1005 * @throws IOException if I/O errors occur while writing to the
1006 * underlying stream
1007 * @throws IllegalArgumentException if the specified stream is not
1008 * the same stream that produced this {@code PutField}
1009 * object
1010 * @deprecated This method does not write the values contained by this
1011 * {@code PutField} object in a proper format, and may
1012 * result in corruption of the serialization stream. The
1013 * correct way to write {@code PutField} data is by
1014 * calling the {@link java.io.ObjectOutputStream#writeFields()}
1015 * method.
1016 */
1017 @Deprecated(forRemoval = true, since = "1.4")
1018 public abstract void write(ObjectOutput out) throws IOException;
1019 }
1020
1021
1022 /**
1023 * Returns protocol version in use.
1024 */
1025 int getProtocolVersion() {
1026 return protocol;
1027 }
1028
1029 /**
1030 * Writes string without allowing it to be replaced in stream. Used by
1031 * ObjectStreamClass to write class descriptor type strings.
1032 */
1033 void writeTypeString(String str) throws IOException {
1034 int handle;
1035 if (str == null) {
1036 writeNull();
1037 } else if ((handle = handles.lookup(str)) != -1) {
1038 writeHandle(handle);
1039 } else {
1040 writeString(str, false);
1041 }
1042 }
1043
1044 /**
1045 * Performs reflective checks on given subclass to verify that it doesn't
1046 * override security-sensitive non-final methods. Returns TRUE if subclass
1047 * is "safe", FALSE otherwise.
1048 */
1049 private static Boolean auditSubclass(Class<?> subcl) {
1050 for (Class<?> cl = subcl;
1051 cl != ObjectOutputStream.class;
1052 cl = cl.getSuperclass())
1053 {
1054 try {
1055 cl.getDeclaredMethod(
1056 "writeUnshared", new Class<?>[] { Object.class });
1057 return Boolean.FALSE;
1058 } catch (NoSuchMethodException ex) {
1059 }
1060 try {
1061 cl.getDeclaredMethod("putFields", (Class<?>[]) null);
1062 return Boolean.FALSE;
1063 } catch (NoSuchMethodException ex) {
1064 }
1065 }
1066 return Boolean.TRUE;
1067 }
1068
1069 /**
1070 * Clears internal data structures.
1071 */
1072 private void clear() {
1073 subs.clear();
1074 handles.clear();
1075 }
1076
1077 /**
1078 * Underlying writeObject/writeUnshared implementation.
1079 */
1080 private void writeObject0(Object obj, boolean unshared)
1081 throws IOException
1082 {
1083 boolean oldMode = bout.setBlockDataMode(false);
1084 depth++;
1085 try {
1086 // handle previously written and non-replaceable objects
1087 int h;
1088 if ((obj = subs.lookup(obj)) == null) {
1089 writeNull();
1090 return;
1091 } else if (!unshared && (h = handles.lookup(obj)) != -1) {
1092 writeHandle(h);
1093 return;
1094 } else if (obj instanceof Class) {
1095 writeClass((Class) obj, unshared);
1096 return;
1097 } else if (obj instanceof ObjectStreamClass) {
1098 writeClassDesc((ObjectStreamClass) obj, unshared);
1099 return;
1100 }
1101
1102 // check for replacement object
1103 Object orig = obj;
1104 Class<?> cl = obj.getClass();
1105 ObjectStreamClass desc;
1106 for (;;) {
1107 // REMIND: skip this check for strings/arrays?
1108 Class<?> repCl;
1109 desc = ObjectStreamClass.lookup(cl, true);
1110 if (!desc.hasWriteReplaceMethod() ||
1111 (obj = desc.invokeWriteReplace(obj)) == null ||
1112 (repCl = obj.getClass()) == cl)
1113 {
1114 break;
1115 }
1116 cl = repCl;
1117 }
1118 if (enableReplace) {
1119 Object rep = replaceObject(obj);
1120 if (rep != obj && rep != null) {
1121 cl = rep.getClass();
1122 desc = ObjectStreamClass.lookup(cl, true);
1123 }
1124 obj = rep;
1125 }
1126
1127 // if object replaced, run through original checks a second time
1128 if (obj != orig) {
1129 subs.assign(orig, obj);
1130 if (obj == null) {
1131 writeNull();
1132 return;
1133 } else if (!unshared && (h = handles.lookup(obj)) != -1) {
1134 writeHandle(h);
1135 return;
1136 } else if (obj instanceof Class) {
1137 writeClass((Class) obj, unshared);
1138 return;
1139 } else if (obj instanceof ObjectStreamClass) {
1140 writeClassDesc((ObjectStreamClass) obj, unshared);
1141 return;
1142 }
1143 }
1144
1145 // remaining cases
1146 if (obj instanceof String) {
1147 writeString((String) obj, unshared);
1148 } else if (cl.isArray()) {
1149 writeArray(obj, desc, unshared);
1150 } else if (obj instanceof Enum) {
1151 writeEnum((Enum<?>) obj, desc, unshared);
1152 } else if (obj instanceof Serializable) {
1153 writeOrdinaryObject(obj, desc, unshared);
1154 } else {
1155 if (extendedDebugInfo) {
1156 throw new NotSerializableException(
1157 cl.getName() + "\n" + debugInfoStack.toString());
1158 } else {
1159 throw new NotSerializableException(cl.getName());
1160 }
1161 }
1162 } finally {
1163 depth--;
1164 bout.setBlockDataMode(oldMode);
1165 }
1166 }
1167
1168 /**
1169 * Writes null code to stream.
1170 */
1171 private void writeNull() throws IOException {
1172 bout.writeByte(TC_NULL);
1173 }
1174
1175 /**
1176 * Writes given object handle to stream.
1177 */
1178 private void writeHandle(int handle) throws IOException {
1179 bout.writeByte(TC_REFERENCE);
1180 bout.writeInt(baseWireHandle + handle);
1181 }
1182
1183 /**
1184 * Writes representation of given class to stream.
1185 */
1186 private void writeClass(Class<?> cl, boolean unshared) throws IOException {
1187 bout.writeByte(TC_CLASS);
1188 writeClassDesc(ObjectStreamClass.lookup(cl, true), false);
1189 handles.assign(unshared ? null : cl);
1190 }
1191
1192 /**
1193 * Writes representation of given class descriptor to stream.
1194 */
1195 private void writeClassDesc(ObjectStreamClass desc, boolean unshared)
1196 throws IOException
1197 {
1198 int handle;
1199 if (desc == null) {
1200 writeNull();
1201 } else if (!unshared && (handle = handles.lookup(desc)) != -1) {
1202 writeHandle(handle);
1203 } else if (desc.isProxy()) {
1204 writeProxyDesc(desc, unshared);
1205 } else {
1206 writeNonProxyDesc(desc, unshared);
1207 }
1208 }
1209
1210 /**
1211 * Writes class descriptor representing a dynamic proxy class to stream.
1212 */
1213 private void writeProxyDesc(ObjectStreamClass desc, boolean unshared)
1214 throws IOException
1215 {
1216 bout.writeByte(TC_PROXYCLASSDESC);
1217 handles.assign(unshared ? null : desc);
1218
1219 Class<?> cl = desc.forClass();
1220 Class<?>[] ifaces = cl.getInterfaces();
1221 bout.writeInt(ifaces.length);
1222 for (int i = 0; i < ifaces.length; i++) {
1223 bout.writeUTF(ifaces[i].getName());
1224 }
1225
1226 bout.setBlockDataMode(true);
1227 annotateProxyClass(cl);
1228 bout.setBlockDataMode(false);
1229 bout.writeByte(TC_ENDBLOCKDATA);
1230
1231 writeClassDesc(desc.getSuperDesc(), false);
1232 }
1233
1234 /**
1235 * Writes class descriptor representing a standard (i.e., not a dynamic
1236 * proxy) class to stream.
1237 */
1238 private void writeNonProxyDesc(ObjectStreamClass desc, boolean unshared)
1239 throws IOException
1240 {
1241 bout.writeByte(TC_CLASSDESC);
1242 handles.assign(unshared ? null : desc);
1243
1244 if (protocol == PROTOCOL_VERSION_1) {
1245 // do not invoke class descriptor write hook with old protocol
1246 desc.writeNonProxy(this);
1247 } else {
1248 writeClassDescriptor(desc);
1249 }
1250
1251 Class<?> cl = desc.forClass();
1252 bout.setBlockDataMode(true);
1253 annotateClass(cl);
1254 bout.setBlockDataMode(false);
1255 bout.writeByte(TC_ENDBLOCKDATA);
1256
1257 writeClassDesc(desc.getSuperDesc(), false);
1258 }
1259
1260 /**
1261 * Writes given string to stream, using standard or long UTF format
1262 * depending on string length.
1263 */
1264 private void writeString(String str, boolean unshared) throws IOException {
1265 handles.assign(unshared ? null : str);
1266 bout.writeUTFInternal(str, true);
1267 }
1268
1269 /**
1270 * Writes given array object to stream.
1271 */
1272 private void writeArray(Object array,
1273 ObjectStreamClass desc,
1274 boolean unshared)
1275 throws IOException
1276 {
1277 bout.writeByte(TC_ARRAY);
1278 writeClassDesc(desc, false);
1279 handles.assign(unshared ? null : array);
1280
1281 Class<?> ccl = desc.forClass().getComponentType();
1282 if (ccl.isPrimitive()) {
1283 if (ccl == Integer.TYPE) {
1284 int[] ia = (int[]) array;
1285 bout.writeInt(ia.length);
1286 bout.writeInts(ia, 0, ia.length);
1287 } else if (ccl == Byte.TYPE) {
1288 byte[] ba = (byte[]) array;
1289 bout.writeInt(ba.length);
1290 bout.write(ba, 0, ba.length, true);
1291 } else if (ccl == Long.TYPE) {
1292 long[] ja = (long[]) array;
1293 bout.writeInt(ja.length);
1294 bout.writeLongs(ja, 0, ja.length);
1295 } else if (ccl == Float.TYPE) {
1296 float[] fa = (float[]) array;
1297 bout.writeInt(fa.length);
1298 bout.writeFloats(fa, 0, fa.length);
1299 } else if (ccl == Double.TYPE) {
1300 double[] da = (double[]) array;
1301 bout.writeInt(da.length);
1302 bout.writeDoubles(da, 0, da.length);
1303 } else if (ccl == Short.TYPE) {
1304 short[] sa = (short[]) array;
1305 bout.writeInt(sa.length);
1306 bout.writeShorts(sa, 0, sa.length);
1307 } else if (ccl == Character.TYPE) {
1308 char[] ca = (char[]) array;
1309 bout.writeInt(ca.length);
1310 bout.writeChars(ca, 0, ca.length);
1311 } else if (ccl == Boolean.TYPE) {
1312 boolean[] za = (boolean[]) array;
1313 bout.writeInt(za.length);
1314 bout.writeBooleans(za, 0, za.length);
1315 } else {
1316 throw new InternalError();
1317 }
1318 } else {
1319 Object[] objs = (Object[]) array;
1320 int len = objs.length;
1321 bout.writeInt(len);
1322 if (extendedDebugInfo) {
1323 debugInfoStack.push(
1324 "array (class \"" + array.getClass().getName() +
1325 "\", size: " + len + ")");
1326 }
1327 try {
1328 for (int i = 0; i < len; i++) {
1329 if (extendedDebugInfo) {
1330 debugInfoStack.push(
1331 "element of array (index: " + i + ")");
1332 }
1333 try {
1334 writeObject0(objs[i], false);
1335 } finally {
1336 if (extendedDebugInfo) {
1337 debugInfoStack.pop();
1338 }
1339 }
1340 }
1341 } finally {
1342 if (extendedDebugInfo) {
1343 debugInfoStack.pop();
1344 }
1345 }
1346 }
1347 }
1348
1349 /**
1350 * Writes given enum constant to stream.
1351 */
1352 private void writeEnum(Enum<?> en,
1353 ObjectStreamClass desc,
1354 boolean unshared)
1355 throws IOException
1356 {
1357 bout.writeByte(TC_ENUM);
1358 ObjectStreamClass sdesc = desc.getSuperDesc();
1359 writeClassDesc((sdesc.forClass() == Enum.class) ? desc : sdesc, false);
1360 handles.assign(unshared ? null : en);
1361 writeString(en.name(), false);
1362 }
1363
1364 /**
1365 * Writes representation of an "ordinary" (i.e., not a String, Class,
1366 * ObjectStreamClass, array, or enum constant) serializable object to the
1367 * stream.
1368 */
1369 private void writeOrdinaryObject(Object obj,
1370 ObjectStreamClass desc,
1371 boolean unshared)
1372 throws IOException
1373 {
1374 if (extendedDebugInfo) {
1375 debugInfoStack.push(
1376 (depth == 1 ? "root " : "") + "object (class \"" +
1377 obj.getClass().getName() + "\", " + obj.toString() + ")");
1378 }
1379 try {
1380 desc.checkSerialize();
1381
1382 bout.writeByte(TC_OBJECT);
1383 writeClassDesc(desc, false);
1384 handles.assign(unshared ? null : obj);
1385
1386 if (desc.isRecord()) {
1387 writeRecordData(obj, desc);
1388 } else if (desc.isExternalizable() && !desc.isProxy()) {
1389 if (desc.isValue())
1390 throw new InvalidClassException("Externalizable not valid for value class "
1391 + desc.forClass().getName());
1392 writeExternalData((Externalizable) obj);
1393 } else {
1394 writeSerialData(obj, desc);
1395 }
1396 } finally {
1397 if (extendedDebugInfo) {
1398 debugInfoStack.pop();
1399 }
1400 }
1401 }
1402
1403 /**
1404 * Writes externalizable data of given object by invoking its
1405 * writeExternal() method.
1406 */
1407 private void writeExternalData(Externalizable obj) throws IOException {
1408 PutFieldImpl oldPut = curPut;
1409 curPut = null;
1410
1411 if (extendedDebugInfo) {
1412 debugInfoStack.push("writeExternal data");
1413 }
1414 SerialCallbackContext oldContext = curContext;
1415 try {
1416 curContext = null;
1417 if (protocol == PROTOCOL_VERSION_1) {
1418 obj.writeExternal(this);
1419 } else {
1420 bout.setBlockDataMode(true);
1421 obj.writeExternal(this);
1422 bout.setBlockDataMode(false);
1423 bout.writeByte(TC_ENDBLOCKDATA);
1424 }
1425 } finally {
1426 curContext = oldContext;
1427 if (extendedDebugInfo) {
1428 debugInfoStack.pop();
1429 }
1430 }
1431
1432 curPut = oldPut;
1433 }
1434
1435 /** Writes the record component values for the given record object. */
1436 private void writeRecordData(Object obj, ObjectStreamClass desc)
1437 throws IOException
1438 {
1439 assert obj.getClass().isRecord();
1440 List<ObjectStreamClass.ClassDataSlot> slots = desc.getClassDataLayout();
1441 if (slots.size() != 1) {
1442 throw new InvalidClassException(
1443 "expected a single record slot length, but found: " + slots.size());
1444 }
1445
1446 defaultWriteFields(obj, desc); // #### seems unnecessary to use the accessors
1447 }
1448
1449 /**
1450 * Writes instance data for each serializable class of given object, from
1451 * superclass to subclass.
1452 */
1453 private void writeSerialData(Object obj, ObjectStreamClass desc)
1454 throws IOException
1455 {
1456 List<ObjectStreamClass.ClassDataSlot> slots = desc.getClassDataLayout();
1457 for (int i = 0; i < slots.size(); i++) {
1458 ObjectStreamClass slotDesc = slots.get(i).desc;
1459 if (slotDesc.hasWriteObjectMethod()) {
1460 PutFieldImpl oldPut = curPut;
1461 curPut = null;
1462 SerialCallbackContext oldContext = curContext;
1463
1464 if (extendedDebugInfo) {
1465 debugInfoStack.push(
1466 "custom writeObject data (class \"" +
1467 slotDesc.getName() + "\")");
1468 }
1469 try {
1470 curContext = new SerialCallbackContext(obj, slotDesc);
1471 bout.setBlockDataMode(true);
1472 slotDesc.invokeWriteObject(obj, this);
1473 bout.setBlockDataMode(false);
1474 bout.writeByte(TC_ENDBLOCKDATA);
1475 } finally {
1476 curContext.setUsed();
1477 curContext = oldContext;
1478 if (extendedDebugInfo) {
1479 debugInfoStack.pop();
1480 }
1481 }
1482
1483 curPut = oldPut;
1484 } else {
1485 defaultWriteFields(obj, slotDesc);
1486 }
1487 }
1488 }
1489
1490 /**
1491 * Fetches and writes values of serializable fields of given object to
1492 * stream. The given class descriptor specifies which field values to
1493 * write, and in which order they should be written.
1494 */
1495 private void defaultWriteFields(Object obj, ObjectStreamClass desc)
1496 throws IOException
1497 {
1498 Class<?> cl = desc.forClass();
1499 if (cl != null && obj != null && !cl.isInstance(obj)) {
1500 throw new ClassCastException();
1501 }
1502
1503 desc.checkDefaultSerialize();
1504
1505 int primDataSize = desc.getPrimDataSize();
1506 if (primDataSize > 0) {
1507 if (primVals == null || primVals.length < primDataSize) {
1508 primVals = new byte[primDataSize];
1509 }
1510 desc.getPrimFieldValues(obj, primVals);
1511 bout.write(primVals, 0, primDataSize, false);
1512 }
1513
1514 int numObjFields = desc.getNumObjFields();
1515 if (numObjFields > 0) {
1516 ObjectStreamField[] fields = desc.getFields(false);
1517 Object[] objVals = new Object[numObjFields];
1518 int numPrimFields = fields.length - objVals.length;
1519 desc.getObjFieldValues(obj, objVals);
1520 for (int i = 0; i < objVals.length; i++) {
1521 if (extendedDebugInfo) {
1522 debugInfoStack.push(
1523 "field (class \"" + desc.getName() + "\", name: \"" +
1524 fields[numPrimFields + i].getName() + "\", type: \"" +
1525 fields[numPrimFields + i].getType() + "\")");
1526 }
1527 try {
1528 writeObject0(objVals[i],
1529 fields[numPrimFields + i].isUnshared());
1530 } finally {
1531 if (extendedDebugInfo) {
1532 debugInfoStack.pop();
1533 }
1534 }
1535 }
1536 }
1537 }
1538
1539 /**
1540 * Attempts to write to stream fatal IOException that has caused
1541 * serialization to abort.
1542 */
1543 private void writeFatalException(IOException ex) throws IOException {
1544 /*
1545 * Note: the serialization specification states that if a second
1546 * IOException occurs while attempting to serialize the original fatal
1547 * exception to the stream, then a StreamCorruptedException should be
1548 * thrown (section 2.1). However, due to a bug in previous
1549 * implementations of serialization, StreamCorruptedExceptions were
1550 * rarely (if ever) actually thrown--the "root" exceptions from
1551 * underlying streams were thrown instead. This historical behavior is
1552 * followed here for consistency.
1553 */
1554 clear();
1555 boolean oldMode = bout.setBlockDataMode(false);
1556 try {
1557 bout.writeByte(TC_EXCEPTION);
1558 writeObject0(ex, false);
1559 clear();
1560 } finally {
1561 bout.setBlockDataMode(oldMode);
1562 }
1563 }
1564
1565 /**
1566 * Default PutField implementation.
1567 */
1568 private class PutFieldImpl extends PutField {
1569
1570 /** class descriptor describing serializable fields */
1571 private final ObjectStreamClass desc;
1572 /** primitive field values */
1573 private final byte[] primVals;
1574 /** object field values */
1575 private final Object[] objVals;
1576
1577 /**
1578 * Creates PutFieldImpl object for writing fields defined in given
1579 * class descriptor.
1580 */
1581 PutFieldImpl(ObjectStreamClass desc) {
1582 this.desc = desc;
1583 primVals = new byte[desc.getPrimDataSize()];
1584 objVals = new Object[desc.getNumObjFields()];
1585 }
1586
1587 public void put(String name, boolean val) {
1588 ByteArray.setBoolean(primVals, getFieldOffset(name, Boolean.TYPE), val);
1589 }
1590
1591 public void put(String name, byte val) {
1592 primVals[getFieldOffset(name, Byte.TYPE)] = val;
1593 }
1594
1595 public void put(String name, char val) {
1596 ByteArray.setChar(primVals, getFieldOffset(name, Character.TYPE), val);
1597 }
1598
1599 public void put(String name, short val) {
1600 ByteArray.setShort(primVals, getFieldOffset(name, Short.TYPE), val);
1601 }
1602
1603 public void put(String name, int val) {
1604 ByteArray.setInt(primVals, getFieldOffset(name, Integer.TYPE), val);
1605 }
1606
1607 public void put(String name, float val) {
1608 ByteArray.setFloat(primVals, getFieldOffset(name, Float.TYPE), val);
1609 }
1610
1611 public void put(String name, long val) {
1612 ByteArray.setLong(primVals, getFieldOffset(name, Long.TYPE), val);
1613 }
1614
1615 public void put(String name, double val) {
1616 ByteArray.setDouble(primVals, getFieldOffset(name, Double.TYPE), val);
1617 }
1618
1619 public void put(String name, Object val) {
1620 objVals[getFieldOffset(name, Object.class)] = val;
1621 }
1622
1623 // deprecated in ObjectOutputStream.PutField
1624 public void write(ObjectOutput out) throws IOException {
1625 /*
1626 * Applications should *not* use this method to write PutField
1627 * data, as it will lead to stream corruption if the PutField
1628 * object writes any primitive data (since block data mode is not
1629 * unset/set properly, as is done in OOS.writeFields()). This
1630 * broken implementation is being retained solely for behavioral
1631 * compatibility, in order to support applications which use
1632 * OOS.PutField.write() for writing only non-primitive data.
1633 *
1634 * Serialization of unshared objects is not implemented here since
1635 * it is not necessary for backwards compatibility; also, unshared
1636 * semantics may not be supported by the given ObjectOutput
1637 * instance. Applications which write unshared objects using the
1638 * PutField API must use OOS.writeFields().
1639 */
1640 if (ObjectOutputStream.this != out) {
1641 throw new IllegalArgumentException("wrong stream");
1642 }
1643 out.write(primVals, 0, primVals.length);
1644
1645 ObjectStreamField[] fields = desc.getFields(false);
1646 int numPrimFields = fields.length - objVals.length;
1647 // REMIND: warn if numPrimFields > 0?
1648 for (int i = 0; i < objVals.length; i++) {
1649 if (fields[numPrimFields + i].isUnshared()) {
1650 throw new IOException("cannot write unshared object");
1651 }
1652 out.writeObject(objVals[i]);
1653 }
1654 }
1655
1656 /**
1657 * Writes buffered primitive data and object fields to stream.
1658 */
1659 void writeFields() throws IOException {
1660 bout.write(primVals, 0, primVals.length, false);
1661
1662 ObjectStreamField[] fields = desc.getFields(false);
1663 int numPrimFields = fields.length - objVals.length;
1664 for (int i = 0; i < objVals.length; i++) {
1665 if (extendedDebugInfo) {
1666 debugInfoStack.push(
1667 "field (class \"" + desc.getName() + "\", name: \"" +
1668 fields[numPrimFields + i].getName() + "\", type: \"" +
1669 fields[numPrimFields + i].getType() + "\")");
1670 }
1671 try {
1672 writeObject0(objVals[i],
1673 fields[numPrimFields + i].isUnshared());
1674 } finally {
1675 if (extendedDebugInfo) {
1676 debugInfoStack.pop();
1677 }
1678 }
1679 }
1680 }
1681
1682 /**
1683 * Returns offset of field with given name and type. A specified type
1684 * of null matches all types, Object.class matches all non-primitive
1685 * types, and any other non-null type matches assignable types only.
1686 * Throws IllegalArgumentException if no matching field found.
1687 */
1688 private int getFieldOffset(String name, Class<?> type) {
1689 ObjectStreamField field = desc.getField(name, type);
1690 if (field == null) {
1691 throw new IllegalArgumentException("no such field " + name +
1692 " with type " + type);
1693 }
1694 return field.getOffset();
1695 }
1696 }
1697
1698 /**
1699 * Buffered output stream with two modes: in default mode, outputs data in
1700 * same format as DataOutputStream; in "block data" mode, outputs data
1701 * bracketed by block data markers (see object serialization specification
1702 * for details).
1703 */
1704 private static final class BlockDataOutputStream
1705 extends OutputStream implements DataOutput
1706 {
1707 /** maximum data block length */
1708 private static final int MAX_BLOCK_SIZE = 1024;
1709 /** maximum data block header length */
1710 private static final int MAX_HEADER_SIZE = 5;
1711 /** (tunable) length of char buffer (for writing strings) */
1712 private static final int CHAR_BUF_SIZE = 256;
1713
1714 /** buffer for writing general/block data */
1715 private final byte[] buf = new byte[MAX_BLOCK_SIZE];
1716 /** buffer for writing block data headers */
1717 private final byte[] hbuf = new byte[MAX_HEADER_SIZE];
1718 /** char buffer for fast string writes */
1719 private final char[] cbuf = new char[CHAR_BUF_SIZE];
1720
1721 /** block data mode */
1722 private boolean blkmode = false;
1723 /** current offset into buf */
1724 private int pos = 0;
1725
1726 /** underlying output stream */
1727 private final OutputStream out;
1728 /** loopback stream (for data writes that span data blocks) */
1729 private final DataOutputStream dout;
1730
1731 /**
1732 * Creates new BlockDataOutputStream on top of given underlying stream.
1733 * Block data mode is turned off by default.
1734 */
1735 BlockDataOutputStream(OutputStream out) {
1736 this.out = out;
1737 dout = new DataOutputStream(this);
1738 }
1739
1740 /**
1741 * Sets block data mode to the given mode (true == on, false == off)
1742 * and returns the previous mode value. If the new mode is the same as
1743 * the old mode, no action is taken. If the new mode differs from the
1744 * old mode, any buffered data is flushed before switching to the new
1745 * mode.
1746 */
1747 boolean setBlockDataMode(boolean mode) throws IOException {
1748 if (blkmode == mode) {
1749 return blkmode;
1750 }
1751 drain();
1752 blkmode = mode;
1753 return !blkmode;
1754 }
1755
1756 /**
1757 * Returns true if the stream is currently in block data mode, false
1758 * otherwise.
1759 */
1760 boolean getBlockDataMode() {
1761 return blkmode;
1762 }
1763
1764 /* ----------------- generic output stream methods ----------------- */
1765 /*
1766 * The following methods are equivalent to their counterparts in
1767 * OutputStream, except that they partition written data into data
1768 * blocks when in block data mode.
1769 */
1770
1771 public void write(int b) throws IOException {
1772 if (pos >= MAX_BLOCK_SIZE) {
1773 drain();
1774 }
1775 buf[pos++] = (byte) b;
1776 }
1777
1778 public void write(byte[] b) throws IOException {
1779 write(b, 0, b.length, false);
1780 }
1781
1782 public void write(byte[] b, int off, int len) throws IOException {
1783 write(b, off, len, false);
1784 }
1785
1786 public void flush() throws IOException {
1787 drain();
1788 out.flush();
1789 }
1790
1791 public void close() throws IOException {
1792 flush();
1793 out.close();
1794 }
1795
1796 /**
1797 * Writes specified span of byte values from given array. If copy is
1798 * true, copies the values to an intermediate buffer before writing
1799 * them to underlying stream (to avoid exposing a reference to the
1800 * original byte array).
1801 */
1802 void write(byte[] b, int off, int len, boolean copy)
1803 throws IOException
1804 {
1805 if (!(copy || blkmode)) { // write directly
1806 drain();
1807 out.write(b, off, len);
1808 return;
1809 }
1810
1811 while (len > 0) {
1812 if (pos >= MAX_BLOCK_SIZE) {
1813 drain();
1814 }
1815 if (len >= MAX_BLOCK_SIZE && !copy && pos == 0) {
1816 // avoid unnecessary copy
1817 writeBlockHeader(MAX_BLOCK_SIZE);
1818 out.write(b, off, MAX_BLOCK_SIZE);
1819 off += MAX_BLOCK_SIZE;
1820 len -= MAX_BLOCK_SIZE;
1821 } else {
1822 int wlen = Math.min(len, MAX_BLOCK_SIZE - pos);
1823 System.arraycopy(b, off, buf, pos, wlen);
1824 pos += wlen;
1825 off += wlen;
1826 len -= wlen;
1827 }
1828 }
1829 }
1830
1831 /**
1832 * Writes all buffered data from this stream to the underlying stream,
1833 * but does not flush underlying stream.
1834 */
1835 void drain() throws IOException {
1836 if (pos == 0) {
1837 return;
1838 }
1839 if (blkmode) {
1840 writeBlockHeader(pos);
1841 }
1842 out.write(buf, 0, pos);
1843 pos = 0;
1844 }
1845
1846 /**
1847 * Writes block data header. Data blocks shorter than 256 bytes are
1848 * prefixed with a 2-byte header; all others start with a 5-byte
1849 * header.
1850 */
1851 private void writeBlockHeader(int len) throws IOException {
1852 if (len <= 0xFF) {
1853 hbuf[0] = TC_BLOCKDATA;
1854 hbuf[1] = (byte) len;
1855 out.write(hbuf, 0, 2);
1856 } else {
1857 hbuf[0] = TC_BLOCKDATALONG;
1858 ByteArray.setInt(hbuf, 1, len);
1859 out.write(hbuf, 0, 5);
1860 }
1861 }
1862
1863
1864 /* ----------------- primitive data output methods ----------------- */
1865 /*
1866 * The following methods are equivalent to their counterparts in
1867 * DataOutputStream, except that they partition written data into data
1868 * blocks when in block data mode.
1869 */
1870
1871 public void writeBoolean(boolean v) throws IOException {
1872 if (pos >= MAX_BLOCK_SIZE) {
1873 drain();
1874 }
1875 ByteArray.setBoolean(buf, pos++, v);
1876 }
1877
1878 public void writeByte(int v) throws IOException {
1879 if (pos >= MAX_BLOCK_SIZE) {
1880 drain();
1881 }
1882 buf[pos++] = (byte) v;
1883 }
1884
1885 public void writeChar(int v) throws IOException {
1886 if (pos + 2 <= MAX_BLOCK_SIZE) {
1887 ByteArray.setChar(buf, pos, (char) v);
1888 pos += 2;
1889 } else {
1890 dout.writeChar(v);
1891 }
1892 }
1893
1894 public void writeShort(int v) throws IOException {
1895 if (pos + 2 <= MAX_BLOCK_SIZE) {
1896 ByteArray.setShort(buf, pos, (short) v);
1897 pos += 2;
1898 } else {
1899 dout.writeShort(v);
1900 }
1901 }
1902
1903 public void writeInt(int v) throws IOException {
1904 if (pos + 4 <= MAX_BLOCK_SIZE) {
1905 ByteArray.setInt(buf, pos, v);
1906 pos += 4;
1907 } else {
1908 dout.writeInt(v);
1909 }
1910 }
1911
1912 public void writeFloat(float v) throws IOException {
1913 if (pos + 4 <= MAX_BLOCK_SIZE) {
1914 ByteArray.setFloat(buf, pos, v);
1915 pos += 4;
1916 } else {
1917 dout.writeFloat(v);
1918 }
1919 }
1920
1921 public void writeLong(long v) throws IOException {
1922 if (pos + 8 <= MAX_BLOCK_SIZE) {
1923 ByteArray.setLong(buf, pos, v);
1924 pos += 8;
1925 } else {
1926 dout.writeLong(v);
1927 }
1928 }
1929
1930 public void writeDouble(double v) throws IOException {
1931 if (pos + 8 <= MAX_BLOCK_SIZE) {
1932 ByteArray.setDouble(buf, pos, v);
1933 pos += 8;
1934 } else {
1935 dout.writeDouble(v);
1936 }
1937 }
1938
1939 @SuppressWarnings("deprecation")
1940 void writeBytes(String s, int len) throws IOException {
1941 int pos = this.pos;
1942 for (int strpos = 0; strpos < len;) {
1943 int rem = MAX_BLOCK_SIZE - pos;
1944 int csize = Math.min(len - strpos, rem);
1945 s.getBytes(strpos, strpos + csize, buf, pos);
1946 pos += csize;
1947 strpos += csize;
1948
1949 if (pos == MAX_BLOCK_SIZE) {
1950 this.pos = pos;
1951 drain();
1952 pos = 0;
1953 }
1954 }
1955 this.pos = pos;
1956 }
1957
1958 public void writeBytes(String s) throws IOException {
1959 writeBytes(s, s.length());
1960 }
1961
1962 public void writeChars(String s) throws IOException {
1963 int endoff = s.length();
1964 for (int off = 0; off < endoff; ) {
1965 int csize = Math.min(endoff - off, CHAR_BUF_SIZE);
1966 s.getChars(off, off + csize, cbuf, 0);
1967 writeChars(cbuf, 0, csize);
1968 off += csize;
1969 }
1970 }
1971
1972 public void writeUTF(String str) throws IOException {
1973 writeUTFInternal(str, false);
1974 }
1975
1976 private void writeUTFInternal(String str, boolean writeHeader) throws IOException {
1977 int strlen = str.length();
1978 int countNonZeroAscii = JLA.countNonZeroAscii(str);
1979 int utflen = utfLen(str, countNonZeroAscii);
1980 if (utflen <= 0xFFFF) {
1981 if(writeHeader) {
1982 writeByte(TC_STRING);
1983 }
1984 writeShort(utflen);
1985 } else {
1986 if(writeHeader) {
1987 writeByte(TC_LONGSTRING);
1988 }
1989 writeLong(utflen);
1990 }
1991
1992 if (countNonZeroAscii != 0) {
1993 writeBytes(str, countNonZeroAscii);
1994 }
1995 if (countNonZeroAscii != strlen) {
1996 writeMoreUTF(str, countNonZeroAscii);
1997 }
1998 }
1999
2000 private void writeMoreUTF(String str, int stroff) throws IOException {
2001 int pos = this.pos;
2002 for (int strlen = str.length(); stroff < strlen;) {
2003 char c = str.charAt(stroff++);
2004 int csize = c != 0 && c < 0x80 ? 1 : c >= 0x800 ? 3 : 2;
2005 if (pos + csize >= MAX_BLOCK_SIZE) {
2006 this.pos = pos;
2007 drain();
2008 pos = 0;
2009 }
2010 pos = putChar(buf, pos, c);
2011 }
2012 this.pos = pos;
2013 }
2014
2015
2016 /* -------------- primitive data array output methods -------------- */
2017 /*
2018 * The following methods write out spans of primitive data values.
2019 * Though equivalent to calling the corresponding primitive write
2020 * methods repeatedly, these methods are optimized for writing groups
2021 * of primitive data values more efficiently.
2022 */
2023
2024 void writeBooleans(boolean[] v, int off, int len) throws IOException {
2025 int endoff = off + len;
2026 while (off < endoff) {
2027 if (pos >= MAX_BLOCK_SIZE) {
2028 drain();
2029 }
2030 int stop = Math.min(endoff, off + (MAX_BLOCK_SIZE - pos));
2031 while (off < stop) {
2032 ByteArray.setBoolean(buf, pos++, v[off++]);
2033 }
2034 }
2035 }
2036
2037 void writeChars(char[] v, int off, int len) throws IOException {
2038 int limit = MAX_BLOCK_SIZE - 2;
2039 int endoff = off + len;
2040 while (off < endoff) {
2041 if (pos <= limit) {
2042 int avail = (MAX_BLOCK_SIZE - pos) >> 1;
2043 int stop = Math.min(endoff, off + avail);
2044 while (off < stop) {
2045 ByteArray.setChar(buf, pos, v[off++]);
2046 pos += 2;
2047 }
2048 } else {
2049 dout.writeChar(v[off++]);
2050 }
2051 }
2052 }
2053
2054 void writeShorts(short[] v, int off, int len) throws IOException {
2055 int limit = MAX_BLOCK_SIZE - 2;
2056 int endoff = off + len;
2057 while (off < endoff) {
2058 if (pos <= limit) {
2059 int avail = (MAX_BLOCK_SIZE - pos) >> 1;
2060 int stop = Math.min(endoff, off + avail);
2061 while (off < stop) {
2062 ByteArray.setShort(buf, pos, v[off++]);
2063 pos += 2;
2064 }
2065 } else {
2066 dout.writeShort(v[off++]);
2067 }
2068 }
2069 }
2070
2071 void writeInts(int[] v, int off, int len) throws IOException {
2072 int limit = MAX_BLOCK_SIZE - 4;
2073 int endoff = off + len;
2074 while (off < endoff) {
2075 if (pos <= limit) {
2076 int avail = (MAX_BLOCK_SIZE - pos) >> 2;
2077 int stop = Math.min(endoff, off + avail);
2078 while (off < stop) {
2079 ByteArray.setInt(buf, pos, v[off++]);
2080 pos += 4;
2081 }
2082 } else {
2083 dout.writeInt(v[off++]);
2084 }
2085 }
2086 }
2087
2088 void writeFloats(float[] v, int off, int len) throws IOException {
2089 int limit = MAX_BLOCK_SIZE - 4;
2090 int endoff = off + len;
2091 while (off < endoff) {
2092 if (pos <= limit) {
2093 int avail = (MAX_BLOCK_SIZE - pos) >> 2;
2094 int stop = Math.min(endoff, off + avail);
2095 while (off < stop) {
2096 ByteArray.setFloat(buf, pos, v[off++]);
2097 pos += 4;
2098 }
2099 } else {
2100 dout.writeFloat(v[off++]);
2101 }
2102 }
2103 }
2104
2105 void writeLongs(long[] v, int off, int len) throws IOException {
2106 int limit = MAX_BLOCK_SIZE - 8;
2107 int endoff = off + len;
2108 while (off < endoff) {
2109 if (pos <= limit) {
2110 int avail = (MAX_BLOCK_SIZE - pos) >> 3;
2111 int stop = Math.min(endoff, off + avail);
2112 while (off < stop) {
2113 ByteArray.setLong(buf, pos, v[off++]);
2114 pos += 8;
2115 }
2116 } else {
2117 dout.writeLong(v[off++]);
2118 }
2119 }
2120 }
2121
2122 void writeDoubles(double[] v, int off, int len) throws IOException {
2123 int limit = MAX_BLOCK_SIZE - 8;
2124 int endoff = off + len;
2125 while (off < endoff) {
2126 if (pos <= limit) {
2127 int avail = (MAX_BLOCK_SIZE - pos) >> 3;
2128 int stop = Math.min(endoff, off + avail);
2129 while (off < stop) {
2130 ByteArray.setDouble(buf, pos, v[off++]);
2131 pos += 8;
2132 }
2133 } else {
2134 dout.writeDouble(v[off++]);
2135 }
2136 }
2137 }
2138 }
2139
2140 /**
2141 * Lightweight identity hash table which maps objects to integer handles,
2142 * assigned in ascending order.
2143 */
2144 private static final class HandleTable {
2145
2146 /* number of mappings in table/next available handle */
2147 private int size;
2148 /* size threshold determining when to expand hash spine */
2149 private int threshold;
2150 /* factor for computing size threshold */
2151 private final float loadFactor;
2152 /* maps hash value -> candidate handle value */
2153 private int[] spine;
2154 /* maps handle value -> next candidate handle value */
2155 private int[] next;
2156 /* maps handle value -> associated object */
2157 private Object[] objs;
2158
2159 /**
2160 * Creates new HandleTable with given capacity and load factor.
2161 */
2162 HandleTable(int initialCapacity, float loadFactor) {
2163 this.loadFactor = loadFactor;
2164 spine = new int[initialCapacity];
2165 next = new int[initialCapacity];
2166 objs = new Object[initialCapacity];
2167 threshold = (int) (initialCapacity * loadFactor);
2168 clear();
2169 }
2170
2171 /**
2172 * Assigns next available handle to given object, and returns handle
2173 * value. Handles are assigned in ascending order starting at 0.
2174 */
2175 int assign(Object obj) {
2176 if (size >= next.length) {
2177 growEntries();
2178 }
2179 if (size >= threshold) {
2180 growSpine();
2181 }
2182 insert(obj, size);
2183 return size++;
2184 }
2185
2186 /**
2187 * Looks up and returns handle associated with given object, or -1 if
2188 * no mapping found.
2189 */
2190 int lookup(Object obj) {
2191 if (size == 0) {
2192 return -1;
2193 }
2194 int index = hash(obj) % spine.length;
2195 for (int i = spine[index]; i >= 0; i = next[i]) {
2196 if (objs[i] == obj) {
2197 return i;
2198 }
2199 }
2200 return -1;
2201 }
2202
2203 /**
2204 * Resets table to its initial (empty) state.
2205 */
2206 void clear() {
2207 Arrays.fill(spine, -1);
2208 Arrays.fill(objs, 0, size, null);
2209 size = 0;
2210 }
2211
2212 /**
2213 * Returns the number of mappings currently in table.
2214 */
2215 int size() {
2216 return size;
2217 }
2218
2219 /**
2220 * Inserts mapping object -> handle mapping into table. Assumes table
2221 * is large enough to accommodate new mapping.
2222 */
2223 private void insert(Object obj, int handle) {
2224 int index = hash(obj) % spine.length;
2225 objs[handle] = obj;
2226 next[handle] = spine[index];
2227 spine[index] = handle;
2228 }
2229
2230 /**
2231 * Expands the hash "spine" -- equivalent to increasing the number of
2232 * buckets in a conventional hash table.
2233 */
2234 private void growSpine() {
2235 spine = new int[(spine.length << 1) + 1];
2236 threshold = (int) (spine.length * loadFactor);
2237 Arrays.fill(spine, -1);
2238 for (int i = 0; i < size; i++) {
2239 insert(objs[i], i);
2240 }
2241 }
2242
2243 /**
2244 * Increases hash table capacity by lengthening entry arrays.
2245 */
2246 private void growEntries() {
2247 int newLength = (next.length << 1) + 1;
2248 int[] newNext = new int[newLength];
2249 System.arraycopy(next, 0, newNext, 0, size);
2250 next = newNext;
2251
2252 Object[] newObjs = new Object[newLength];
2253 System.arraycopy(objs, 0, newObjs, 0, size);
2254 objs = newObjs;
2255 }
2256
2257 /**
2258 * Returns hash value for given object.
2259 */
2260 private int hash(Object obj) {
2261 return System.identityHashCode(obj) & 0x7FFFFFFF;
2262 }
2263 }
2264
2265 /**
2266 * Lightweight identity hash table which maps objects to replacement
2267 * objects.
2268 */
2269 private static final class ReplaceTable {
2270
2271 /* maps object -> index */
2272 private final HandleTable htab;
2273 /* maps index -> replacement object */
2274 private Object[] reps;
2275
2276 /**
2277 * Creates new ReplaceTable with given capacity and load factor.
2278 */
2279 ReplaceTable(int initialCapacity, float loadFactor) {
2280 htab = new HandleTable(initialCapacity, loadFactor);
2281 reps = new Object[initialCapacity];
2282 }
2283
2284 /**
2285 * Enters mapping from object to replacement object.
2286 */
2287 void assign(Object obj, Object rep) {
2288 int index = htab.assign(obj);
2289 while (index >= reps.length) {
2290 grow();
2291 }
2292 reps[index] = rep;
2293 }
2294
2295 /**
2296 * Looks up and returns replacement for given object. If no
2297 * replacement is found, returns the lookup object itself.
2298 */
2299 Object lookup(Object obj) {
2300 int index = htab.lookup(obj);
2301 return (index >= 0) ? reps[index] : obj;
2302 }
2303
2304 /**
2305 * Resets table to its initial (empty) state.
2306 */
2307 void clear() {
2308 Arrays.fill(reps, 0, htab.size(), null);
2309 htab.clear();
2310 }
2311
2312 /**
2313 * Returns the number of mappings currently in table.
2314 */
2315 int size() {
2316 return htab.size();
2317 }
2318
2319 /**
2320 * Increases table capacity.
2321 */
2322 private void grow() {
2323 Object[] newReps = new Object[(reps.length << 1) + 1];
2324 System.arraycopy(reps, 0, newReps, 0, reps.length);
2325 reps = newReps;
2326 }
2327 }
2328
2329 /**
2330 * Stack to keep debug information about the state of the
2331 * serialization process, for embedding in exception messages.
2332 */
2333 private static final class DebugTraceInfoStack {
2334 private final List<String> stack;
2335
2336 DebugTraceInfoStack() {
2337 stack = new ArrayList<>();
2338 }
2339
2340 /**
2341 * Removes all of the elements from enclosed list.
2342 */
2343 void clear() {
2344 stack.clear();
2345 }
2346
2347 /**
2348 * Removes the object at the top of enclosed list.
2349 */
2350 void pop() {
2351 stack.remove(stack.size()-1);
2352 }
2353
2354 /**
2355 * Pushes a String onto the top of enclosed list.
2356 */
2357 void push(String entry) {
2358 stack.add("\t- " + entry);
2359 }
2360
2361 /**
2362 * Returns a string representation of this object
2363 */
2364 public String toString() {
2365 StringJoiner sj = new StringJoiner("\n");
2366 for (int i = stack.size() - 1; i >= 0; i--) {
2367 sj.add(stack.get(i));
2368 }
2369 return sj.toString();
2370 }
2371 }
2372
2373 }