1 /*
2 * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javax.sql.rowset.serial;
27
28 import java.sql.*;
29 import java.io.*;
30 import java.lang.reflect.*;
31 import java.util.Arrays;
32
33
34 /**
35 * A serialized mapping in the Java programming language of an SQL
36 * <code>BLOB</code> value.
37 * <P>
38 * The <code>SerialBlob</code> class provides a constructor for creating
39 * an instance from a <code>Blob</code> object. Note that the
40 * <code>Blob</code>
41 * object should have brought the SQL <code>BLOB</code> value's data over
42 * to the client before a <code>SerialBlob</code> object
43 * is constructed from it. The data of an SQL <code>BLOB</code> value can
44 * be materialized on the client as an array of bytes (using the method
45 * <code>Blob.getBytes</code>) or as a stream of uninterpreted bytes
46 * (using the method <code>Blob.getBinaryStream</code>).
47 * <P>
48 * <code>SerialBlob</code> methods make it possible to make a copy of a
49 * <code>SerialBlob</code> object as an array of bytes or as a stream.
50 * They also make it possible to locate a given pattern of bytes or a
51 * <code>Blob</code> object within a <code>SerialBlob</code> object
52 * and to update or truncate a <code>Blob</code> object.
53 *
54 * <h2> Thread safety </h2>
55 *
56 * <p> A SerialBlob is not safe for use by multiple concurrent threads. If a
57 * SerialBlob is to be used by more than one thread then access to the SerialBlob
58 * should be controlled by appropriate synchronization.
59 *
60 * @author Jonathan Bruce
61 * @since 1.5
62 */
63 public class SerialBlob implements Blob, Serializable, Cloneable {
64
65 /**
66 * A serialized array of uninterpreted bytes representing the
67 * value of this <code>SerialBlob</code> object.
68 * @serial
69 */
70 private byte[] buf;
71
72 /**
73 * The internal representation of the <code>Blob</code> object on which this
74 * <code>SerialBlob</code> object is based.
75 */
76 @SuppressWarnings("serial") // Not statically typed as Serializable; checked in writeObject
77 private Blob blob;
78
79 /**
80 * The number of bytes in this <code>SerialBlob</code> object's
81 * array of bytes.
82 * @serial
83 */
84 private long len;
85
86 /**
87 * The original number of bytes in this <code>SerialBlob</code> object's
88 * array of bytes when it was first established.
89 * @serial
90 */
91 private long origLen;
92
93 /**
94 * Constructs a <code>SerialBlob</code> object that is a serialized version of
95 * the given <code>byte</code> array.
96 * <p>
97 * The new <code>SerialBlob</code> object is initialized with the data from the
98 * <code>byte</code> array, thus allowing disconnected <code>RowSet</code>
99 * objects to establish serialized <code>Blob</code> objects without
100 * touching the data source.
101 *
102 * @param b the <code>byte</code> array containing the data for the
103 * <code>Blob</code> object to be serialized
104 * @throws SerialException if an error occurs during serialization
105 * @throws SQLException if a SQL errors occurs
106 */
107 public SerialBlob(byte[] b)
108 throws SerialException, SQLException {
109
110 len = b.length;
111 buf = new byte[(int)len];
112 for(int i = 0; i < len; i++) {
113 buf[i] = b[i];
114 }
115 origLen = len;
116 }
117
118
119 /**
120 * Constructs a <code>SerialBlob</code> object that is a serialized
121 * version of the given <code>Blob</code> object.
122 * <P>
123 * The new <code>SerialBlob</code> object is initialized with the
124 * data from the <code>Blob</code> object; therefore, the
125 * <code>Blob</code> object should have previously brought the
126 * SQL <code>BLOB</code> value's data over to the client from
127 * the database. Otherwise, the new <code>SerialBlob</code> object
128 * will contain no data.
129 *
130 * @param blob the <code>Blob</code> object from which this
131 * <code>SerialBlob</code> object is to be constructed;
132 * cannot be null.
133 * @throws SerialException if an error occurs during serialization
134 * @throws SQLException if the <code>Blob</code> passed to this
135 * to this constructor is a <code>null</code>.
136 * @see java.sql.Blob
137 */
138 public SerialBlob (Blob blob)
139 throws SerialException, SQLException {
140
141 if (blob == null) {
142 throw new SQLException(
143 "Cannot instantiate a SerialBlob object with a null Blob object");
144 }
145
146 len = blob.length();
147 buf = blob.getBytes(1, (int)len );
148 this.blob = blob;
149 origLen = len;
150 }
151
152 /**
153 * Copies the specified number of bytes, starting at the given
154 * position, from this <code>SerialBlob</code> object to
155 * another array of bytes.
156 * <P>
157 * Note that if the given number of bytes to be copied is larger than
158 * the length of this <code>SerialBlob</code> object's array of
159 * bytes, the given number will be shortened to the array's length.
160 *
161 * @param pos the ordinal position of the first byte in this
162 * <code>SerialBlob</code> object to be copied;
163 * numbering starts at <code>1</code>; must not be less
164 * than <code>1</code> and must be less than or equal
165 * to the length of this <code>SerialBlob</code> object
166 * @param length the number of bytes to be copied
167 * @return an array of bytes that is a copy of a region of this
168 * <code>SerialBlob</code> object, starting at the given
169 * position and containing the given number of consecutive bytes
170 * @throws SerialException if the given starting position is out of bounds;
171 * if {@code free} had previously been called on this object
172 */
173 public byte[] getBytes(long pos, int length) throws SerialException {
174 isValid();
175 if (length > len) {
176 length = (int)len;
177 }
178
179 if (pos < 1 || len - pos < 0 ) {
180 throw new SerialException("Invalid arguments: position cannot be "
181 + "less than 1 or greater than the length of the SerialBlob");
182 }
183
184 pos--; // correct pos to array index
185
186 byte[] b = new byte[length];
187
188 for (int i = 0; i < length; i++) {
189 b[i] = this.buf[(int)pos];
190 pos++;
191 }
192 return b;
193 }
194
195 /**
196 * Retrieves the number of bytes in this <code>SerialBlob</code>
197 * object's array of bytes.
198 *
199 * @return a <code>long</code> indicating the length in bytes of this
200 * <code>SerialBlob</code> object's array of bytes
201 * @throws SerialException if an error occurs;
202 * if {@code free} had previously been called on this object
203 */
204 public long length() throws SerialException {
205 isValid();
206 return len;
207 }
208
209 /**
210 * Returns this <code>SerialBlob</code> object as an input stream.
211 * Unlike the related method, <code>setBinaryStream</code>,
212 * a stream is produced regardless of whether the <code>SerialBlob</code>
213 * was created with a <code>Blob</code> object or a <code>byte</code> array.
214 *
215 * @return a <code>java.io.InputStream</code> object that contains
216 * this <code>SerialBlob</code> object's array of bytes
217 * @throws SerialException if an error occurs;
218 * if {@code free} had previously been called on this object
219 * @see #setBinaryStream
220 */
221 public java.io.InputStream getBinaryStream() throws SerialException {
222 isValid();
223 InputStream stream = new ByteArrayInputStream(buf);
224 return stream;
225 }
226
227 /**
228 * Returns the position in this <code>SerialBlob</code> object where
229 * the given pattern of bytes begins, starting the search at the
230 * specified position.
231 *
232 * @param pattern the pattern of bytes for which to search
233 * @param start the position of the byte in this
234 * <code>SerialBlob</code> object from which to begin
235 * the search; the first position is <code>1</code>;
236 * must not be less than <code>1</code> nor greater than
237 * the length of this <code>SerialBlob</code> object
238 * @return the position in this <code>SerialBlob</code> object
239 * where the given pattern begins, starting at the specified
240 * position; <code>-1</code> if the pattern is not found
241 * or the given starting position is out of bounds; position
242 * numbering for the return value starts at <code>1</code>
243 * @throws SerialException if an error occurs when serializing the blob;
244 * if {@code free} had previously been called on this object
245 * @throws SQLException if there is an error accessing the <code>BLOB</code>
246 * value from the database
247 */
248 public long position(byte[] pattern, long start)
249 throws SerialException, SQLException {
250
251 isValid();
252 if (start < 1 || start > len) {
253 return -1;
254 }
255
256 int pos = (int)start-1; // internally Blobs are stored as arrays.
257 int i = 0;
258 long patlen = pattern.length;
259
260 while (pos < len) {
261 if (pattern[i] == buf[pos]) {
262 if (i + 1 == patlen) {
263 return (pos + 1) - (patlen - 1);
264 }
265 i++; pos++; // increment pos, and i
266 } else if (pattern[i] != buf[pos]) {
267 pos++; // increment pos only
268 }
269 }
270 return -1; // not found
271 }
272
273 /**
274 * Returns the position in this <code>SerialBlob</code> object where
275 * the given <code>Blob</code> object begins, starting the search at the
276 * specified position.
277 *
278 * @param pattern the <code>Blob</code> object for which to search;
279 * @param start the position of the byte in this
280 * <code>SerialBlob</code> object from which to begin
281 * the search; the first position is <code>1</code>;
282 * must not be less than <code>1</code> nor greater than
283 * the length of this <code>SerialBlob</code> object
284 * @return the position in this <code>SerialBlob</code> object
285 * where the given <code>Blob</code> object begins, starting
286 * at the specified position; <code>-1</code> if the pattern is
287 * not found or the given starting position is out of bounds;
288 * position numbering for the return value starts at <code>1</code>
289 * @throws SerialException if an error occurs when serializing the blob;
290 * if {@code free} had previously been called on this object
291 * @throws SQLException if there is an error accessing the <code>BLOB</code>
292 * value from the database
293 */
294 public long position(Blob pattern, long start)
295 throws SerialException, SQLException {
296 isValid();
297 return position(pattern.getBytes(1, (int)(pattern.length())), start);
298 }
299
300 /**
301 * Writes the given array of bytes to the <code>BLOB</code> value that
302 * this <code>Blob</code> object represents, starting at position
303 * <code>pos</code>, and returns the number of bytes written.
304 *
305 * @param pos the position in the SQL <code>BLOB</code> value at which
306 * to start writing. The first position is <code>1</code>;
307 * must not be less than <code>1</code> nor greater than
308 * the length of this <code>SerialBlob</code> object.
309 * @param bytes the array of bytes to be written to the <code>BLOB</code>
310 * value that this <code>Blob</code> object represents
311 * @return the number of bytes written
312 * @throws SerialException if there is an error accessing the
313 * <code>BLOB</code> value; or if an invalid position is set; if an
314 * invalid offset value is set;
315 * if {@code free} had previously been called on this object
316 * @throws SQLException if there is an error accessing the <code>BLOB</code>
317 * value from the database
318 * @see #getBytes
319 */
320 public int setBytes(long pos, byte[] bytes)
321 throws SerialException, SQLException {
322 return setBytes(pos, bytes, 0, bytes.length);
323 }
324
325 /**
326 * Writes all or part of the given <code>byte</code> array to the
327 * <code>BLOB</code> value that this <code>Blob</code> object represents
328 * and returns the number of bytes written.
329 * Writing starts at position <code>pos</code> in the <code>BLOB</code>
330 * value; <i>len</i> bytes from the given byte array are written.
331 *
332 * @param pos the position in the <code>BLOB</code> object at which
333 * to start writing. The first position is <code>1</code>;
334 * must not be less than <code>1</code> nor greater than
335 * the length of this <code>SerialBlob</code> object.
336 * @param bytes the array of bytes to be written to the <code>BLOB</code>
337 * value
338 * @param offset the offset in the <code>byte</code> array at which
339 * to start reading the bytes. The first offset position is
340 * <code>0</code>; must not be less than <code>0</code> nor greater
341 * than the length of the <code>byte</code> array
342 * @param length the number of bytes to be written to the
343 * <code>BLOB</code> value from the array of bytes <i>bytes</i>.
344 *
345 * @return the number of bytes written
346 * @throws SerialException if there is an error accessing the
347 * <code>BLOB</code> value; if an invalid position is set; if an
348 * invalid offset value is set; if number of bytes to be written
349 * is greater than the <code>SerialBlob</code> length; or the combined
350 * values of the length and offset is greater than the Blob buffer;
351 * if {@code free} had previously been called on this object
352 * @throws SQLException if there is an error accessing the <code>BLOB</code>
353 * value from the database.
354 * @see #getBytes
355 */
356 public int setBytes(long pos, byte[] bytes, int offset, int length)
357 throws SerialException, SQLException {
358
359 isValid();
360 if (offset < 0 || offset > bytes.length) {
361 throw new SerialException("Invalid offset in byte array set");
362 }
363
364 if (pos < 1 || pos > this.length()) {
365 throw new SerialException("Invalid position in BLOB object set");
366 }
367
368 if ((long)(length) > origLen) {
369 throw new SerialException("Buffer is not sufficient to hold the value");
370 }
371
372 if ((length + offset) > bytes.length) {
373 throw new SerialException("Invalid OffSet. Cannot have combined offset " +
374 "and length that is greater that the Blob buffer");
375 }
376
377 int i = 0;
378 pos--; // correct to array indexing
379 while ( i < length || (offset + i +1) < (bytes.length-offset) ) {
380 this.buf[(int)pos + i] = bytes[offset + i ];
381 i++;
382 }
383 return i;
384 }
385
386 /**
387 * Retrieves a stream that can be used to write to the <code>BLOB</code>
388 * value that this <code>Blob</code> object represents. The stream begins
389 * at position <code>pos</code>. This method forwards the
390 * <code>setBinaryStream()</code> call to the underlying <code>Blob</code> in
391 * the event that this <code>SerialBlob</code> object is instantiated with a
392 * <code>Blob</code>. If this <code>SerialBlob</code> is instantiated with
393 * a <code>byte</code> array, a <code>SerialException</code> is thrown.
394 *
395 * @param pos the position in the <code>BLOB</code> value at which
396 * to start writing
397 * @return a <code>java.io.OutputStream</code> object to which data can
398 * be written
399 * @throws SQLException if there is an error accessing the
400 * <code>BLOB</code> value
401 * @throws SerialException if the SerialBlob in not instantiated with a
402 * <code>Blob</code> object that supports <code>setBinaryStream()</code>;
403 * if {@code free} had previously been called on this object
404 * @see #getBinaryStream
405 */
406 public java.io.OutputStream setBinaryStream(long pos)
407 throws SerialException, SQLException {
408
409 isValid();
410 if (this.blob != null) {
411 return this.blob.setBinaryStream(pos);
412 } else {
413 throw new SerialException("Unsupported operation. SerialBlob cannot " +
414 "return a writable binary stream, unless instantiated with a Blob object " +
415 "that provides a setBinaryStream() implementation");
416 }
417 }
418
419 /**
420 * Truncates the <code>BLOB</code> value that this <code>Blob</code>
421 * object represents to be <code>len</code> bytes in length.
422 *
423 * @param length the length, in bytes, to which the <code>BLOB</code>
424 * value that this <code>Blob</code> object represents should be
425 * truncated
426 * @throws SerialException if there is an error accessing the Blob value;
427 * or the length to truncate is greater that the SerialBlob length;
428 * if {@code free} had previously been called on this object
429 */
430 public void truncate(long length) throws SerialException {
431 isValid();
432 if (length > len) {
433 throw new SerialException(
434 "Length more than what can be truncated");
435 } else if((int)length == 0) {
436 buf = new byte[0];
437 len = length;
438 } else {
439 len = length;
440 buf = this.getBytes(1, (int)len);
441 }
442 }
443
444
445 /**
446 * Returns an
447 * <code>InputStream</code> object that contains a partial
448 * {@code Blob} value, starting with the byte specified by pos, which is
449 * length bytes in length.
450 *
451 * @param pos the offset to the first byte of the partial value to be
452 * retrieved. The first byte in the {@code Blob} is at position 1
453 * @param length the length in bytes of the partial value to be retrieved
454 * @return
455 * <code>InputStream</code> through which the partial {@code Blob} value can
456 * be read.
457 * @throws SQLException if pos is less than 1 or if pos is greater than the
458 * number of bytes in the {@code Blob} or if pos + length is greater than
459 * the number of bytes in the {@code Blob}
460 * @throws SerialException if the {@code free} method had been previously
461 * called on this object
462 *
463 * @since 1.6
464 */
465 public InputStream getBinaryStream(long pos, long length) throws SQLException {
466 isValid();
467 if (pos < 1 || pos > this.length()) {
468 throw new SerialException("Invalid position in BLOB object set");
469 }
470 if (length < 1 || length > len - pos + 1) {
471 throw new SerialException(
472 "length is < 1 or pos + length > total number of bytes");
473 }
474 return new ByteArrayInputStream(buf, (int) pos - 1, (int) length);
475 }
476
477
478 /**
479 * This method frees the {@code SerialBlob} object and releases the
480 * resources that it holds. The object is invalid once the {@code free}
481 * method is called. <p> If {@code free} is called multiple times, the
482 * subsequent calls to {@code free} are treated as a no-op. </P>
483 *
484 * @throws SQLException if an error occurs releasing the Blob's resources
485 * @since 1.6
486 */
487 public void free() throws SQLException {
488 if (buf != null) {
489 buf = null;
490 if (blob != null) {
491 blob.free();
492 }
493 blob = null;
494 }
495 }
496
497 /**
498 * Compares this SerialBlob to the specified object. The result is {@code
499 * true} if and only if the argument is not {@code null} and is a {@code
500 * SerialBlob} object that represents the same sequence of bytes as this
501 * object.
502 *
503 * @param obj The object to compare this {@code SerialBlob} against
504 *
505 * @return {@code true} if the given object represents a {@code SerialBlob}
506 * equivalent to this SerialBlob, {@code false} otherwise
507 *
508 */
509 public boolean equals(Object obj) {
510 if (this == obj) {
511 return true;
512 }
513 if (obj instanceof SerialBlob) {
514 SerialBlob sb = (SerialBlob)obj;
515 if (this.len == sb.len) {
516 return Arrays.equals(buf, sb.buf);
517 }
518 }
519 return false;
520 }
521
522 /**
523 * Returns a hash code for this {@code SerialBlob}.
524 * @return a hash code value for this object.
525 */
526 public int hashCode() {
527 return ((31 + Arrays.hashCode(buf)) * 31 + (int)len) * 31 + (int)origLen;
528 }
529
530 /**
531 * Returns a clone of this {@code SerialBlob}. The copy will contain a
532 * reference to a clone of the internal byte array, not a reference
533 * to the original internal byte array of this {@code SerialBlob} object.
534 * The underlying {@code Blob} object will be set to null.
535 *
536 * @return a clone of this SerialBlob
537 */
538 public Object clone() {
539 try {
540 SerialBlob sb = (SerialBlob) super.clone();
541 sb.buf = (buf != null) ? Arrays.copyOf(buf, (int)len) : null;
542 sb.blob = null;
543 return sb;
544 } catch (CloneNotSupportedException ex) {
545 // this shouldn't happen, since we are Cloneable
546 throw new InternalError();
547 }
548 }
549
550 /**
551 * readObject is called to restore the state of the SerialBlob from
552 * a stream.
553 * @param s the {@code ObjectInputStream} to read from.
554 *
555 * @throws ClassNotFoundException if the class of a serialized object
556 * could not be found.
557 * @throws IOException if an I/O error occurs.
558 */
559 private void readObject(ObjectInputStream s)
560 throws IOException, ClassNotFoundException {
561
562 ObjectInputStream.GetField fields = s.readFields();
563 byte[] tmp = (byte[])fields.get("buf", null);
564 if (tmp == null)
565 throw new InvalidObjectException("buf is null and should not be!");
566 buf = tmp.clone();
567 len = fields.get("len", 0L);
568 if (buf.length != len)
569 throw new InvalidObjectException("buf is not the expected size");
570 origLen = fields.get("origLen", 0L);
571 blob = (Blob) fields.get("blob", null);
572 }
573
574 /**
575 * writeObject is called to save the state of the SerialBlob
576 * to a stream.
577 * @param s the {@code ObjectOutputStream} to write to.
578 + @throws IOException if I/O errors occur.
579 */
580 private void writeObject(ObjectOutputStream s)
581 throws IOException {
582
583 ObjectOutputStream.PutField fields = s.putFields();
584 fields.put("buf", buf);
585 fields.put("len", len);
586 fields.put("origLen", origLen);
587 // Note: this check to see if it is an instance of Serializable
588 // is for backwards compatibility
589 fields.put("blob", blob instanceof Serializable ? blob : null);
590 s.writeFields();
591 }
592
593 /**
594 * Check to see if this object had previously had its {@code free} method
595 * called
596 *
597 * @throws SerialException
598 */
599 private void isValid() throws SerialException {
600 if (buf == null) {
601 throw new SerialException("Error: You cannot call a method on a " +
602 "SerialBlob instance once free() has been called.");
603 }
604 }
605
606 /**
607 * The identifier that assists in the serialization of this
608 * {@code SerialBlob} object.
609 */
610 static final long serialVersionUID = -8144641928112860441L;
611 }