1 /*
2 * Copyright (c) 2003, 2012, 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 * @author Jonathan Bruce
55 */
56 public class SerialBlob implements Blob, Serializable, Cloneable {
57
58 /**
59 * A serialized array of uninterpreted bytes representing the
60 * value of this <code>SerialBlob</code> object.
61 * @serial
62 */
63 private byte buf[];
64
65 /**
66 * The internal representation of the <code>Blob</code> object on which this
67 * <code>SerialBlob</code> object is based.
68 */
69 private Blob blob;
70
71 /**
72 * The number of bytes in this <code>SerialBlob</code> object's
73 * array of bytes.
74 * @serial
75 */
76 private long len;
77
78 /**
79 * The orginal number of bytes in this <code>SerialBlob</code> object's
80 * array of bytes when it was first established.
81 * @serial
82 */
83 private long origLen;
84
85 /**
86 * Constructs a <code>SerialBlob</code> object that is a serialized version of
87 * the given <code>byte</code> array.
88 * <p>
89 * The new <code>SerialBlob</code> object is initialized with the data from the
90 * <code>byte</code> array, thus allowing disconnected <code>RowSet</code>
91 * objects to establish serialized <code>Blob</code> objects without
92 * touching the data source.
93 *
94 * @param b the <code>byte</code> array containing the data for the
95 * <code>Blob</code> object to be serialized
96 * @throws SerialException if an error occurs during serialization
97 * @throws SQLException if a SQL errors occurs
98 */
99 public SerialBlob(byte[] b) throws SerialException, SQLException {
100
101 len = b.length;
102 buf = new byte[(int)len];
103 for(int i = 0; i < len; i++) {
104 buf[i] = b[i];
105 }
106 origLen = len;
107 }
108
109
110 /**
111 * Constructs a <code>SerialBlob</code> object that is a serialized
112 * version of the given <code>Blob</code> object.
113 * <P>
114 * The new <code>SerialBlob</code> object is initialized with the
115 * data from the <code>Blob</code> object; therefore, the
116 * <code>Blob</code> object should have previously brought the
117 * SQL <code>BLOB</code> value's data over to the client from
118 * the database. Otherwise, the new <code>SerialBlob</code> object
119 * will contain no data.
120 *
121 * @param blob the <code>Blob</code> object from which this
122 * <code>SerialBlob</code> object is to be constructed;
123 * cannot be null.
124 * @throws SerialException if an error occurs during serialization
125 * @throws SQLException if the <code>Blob</code> passed to this
126 * to this constructor is a <code>null</code>.
127 * @see java.sql.Blob
128 */
129 public SerialBlob (Blob blob) throws SerialException, SQLException {
130
131 if (blob == null) {
132 throw new SQLException("Cannot instantiate a SerialBlob " +
133 "object with a null Blob object");
134 }
135
136 len = blob.length();
137 buf = blob.getBytes(1, (int)len );
138 this.blob = blob;
139
140 //if ( len < 10240000)
141 // len = 10240000;
142 origLen = len;
143 }
144
145 /**
146 * Copies the specified number of bytes, starting at the given
147 * position, from this <code>SerialBlob</code> object to
148 * another array of bytes.
149 * <P>
150 * Note that if the given number of bytes to be copied is larger than
151 * the length of this <code>SerialBlob</code> object's array of
152 * bytes, the given number will be shortened to the array's length.
153 *
154 * @param pos the ordinal position of the first byte in this
155 * <code>SerialBlob</code> object to be copied;
156 * numbering starts at <code>1</code>; must not be less
157 * than <code>1</code> and must be less than or equal
158 * to the length of this <code>SerialBlob</code> object
159 * @param length the number of bytes to be copied
160 * @return an array of bytes that is a copy of a region of this
161 * <code>SerialBlob</code> object, starting at the given
162 * position and containing the given number of consecutive bytes
163 * @throws SerialException if the given starting position is out of bounds
164 */
165 public byte[] getBytes(long pos, int length) throws SerialException {
166 if (length > len) {
167 length = (int)len;
168 }
169
170 if (pos < 1 || len - pos < 0 ) {
171 throw new SerialException("Invalid arguments: position cannot be "
172 + "less than 1 or greater than the length of the SerialBlob");
173 }
174
175 pos--; // correct pos to array index
176
177 byte[] b = new byte[length];
178
179 for (int i = 0; i < length; i++) {
180 b[i] = this.buf[(int)pos];
181 pos++;
182 }
183 return b;
184 }
185
186 /**
187 * Retrieves the number of bytes in this <code>SerialBlob</code>
188 * object's array of bytes.
189 *
190 * @return a <code>long</code> indicating the length in bytes of this
191 * <code>SerialBlob</code> object's array of bytes
192 * @throws SerialException if an error occurs
193 */
194 public long length() throws SerialException {
195 return len;
196 }
197
198 /**
199 * Returns this <code>SerialBlob</code> object as an input stream.
200 * Unlike the related method, <code>setBinaryStream</code>,
201 * a stream is produced regardless of whether the <code>SerialBlob</code>
202 * was created with a <code>Blob</code> object or a <code>byte</code> array.
203 *
204 * @return a <code>java.io.InputStream</code> object that contains
205 * this <code>SerialBlob</code> object's array of bytes
206 * @throws SerialException if an error occurs
207 * @see #setBinaryStream
208 */
209 public java.io.InputStream getBinaryStream() throws SerialException {
210 InputStream stream = new ByteArrayInputStream(buf);
211 return stream;
212 }
213
214 /**
215 * Returns the position in this <code>SerialBlob</code> object where
216 * the given pattern of bytes begins, starting the search at the
217 * specified position.
218 *
219 * @param pattern the pattern of bytes for which to search
220 * @param start the position of the byte in this
221 * <code>SerialBlob</code> object from which to begin
222 * the search; the first position is <code>1</code>;
223 * must not be less than <code>1</code> nor greater than
224 * the length of this <code>SerialBlob</code> object
225 * @return the position in this <code>SerialBlob</code> object
226 * where the given pattern begins, starting at the specified
227 * position; <code>-1</code> if the pattern is not found
228 * or the given starting position is out of bounds; position
229 * numbering for the return value starts at <code>1</code>
230 * @throws SerialException if an error occurs when serializing the blob
231 * @throws SQLException if there is an error accessing the <code>BLOB</code>
232 * value from the database
233 */
234 public long position(byte[] pattern, long start)
235 throws SerialException, SQLException {
236 if (start < 1 || start > len) {
237 return -1;
238 }
239
240 int pos = (int)start-1; // internally Blobs are stored as arrays.
241 int i = 0;
242 long patlen = pattern.length;
243
244 while (pos < len) {
245 if (pattern[i] == buf[pos]) {
246 if (i + 1 == patlen) {
247 return (pos + 1) - (patlen - 1);
248 }
249 i++; pos++; // increment pos, and i
250 } else if (pattern[i] != buf[pos]) {
251 pos++; // increment pos only
252 }
253 }
254 return -1; // not found
255 }
256
257 /**
258 * Returns the position in this <code>SerialBlob</code> object where
259 * the given <code>Blob</code> object begins, starting the search at the
260 * specified position.
261 *
262 * @param pattern the <code>Blob</code> object for which to search;
263 * @param start the position of the byte in this
264 * <code>SerialBlob</code> object from which to begin
265 * the search; the first position is <code>1</code>;
266 * must not be less than <code>1</code> nor greater than
267 * the length of this <code>SerialBlob</code> object
268 * @return the position in this <code>SerialBlob</code> object
269 * where the given <code>Blob</code> object begins, starting
270 * at the specified position; <code>-1</code> if the pattern is
271 * not found or the given starting position is out of bounds;
272 * position numbering for the return value starts at <code>1</code>
273 * @throws SerialException if an error occurs when serializing the blob
274 * @throws SQLException if there is an error accessing the <code>BLOB</code>
275 * value from the database
276 */
277 public long position(Blob pattern, long start)
278 throws SerialException, SQLException {
279 return position(pattern.getBytes(1, (int)(pattern.length())), start);
280 }
281
282 /**
283 * Writes the given array of bytes to the <code>BLOB</code> value that
284 * this <code>Blob</code> object represents, starting at position
285 * <code>pos</code>, and returns the number of bytes written.
286 *
287 * @param pos the position in the SQL <code>BLOB</code> value at which
288 * to start writing. The first position is <code>1</code>;
289 * must not be less than <code>1</code> nor greater than
290 * the length of this <code>SerialBlob</code> object.
291 * @param bytes the array of bytes to be written to the <code>BLOB</code>
292 * value that this <code>Blob</code> object represents
293 * @return the number of bytes written
294 * @throws SerialException if there is an error accessing the
295 * <code>BLOB</code> value; or if an invalid position is set; if an
296 * invalid offset value is set
297 * @throws SQLException if there is an error accessing the <code>BLOB</code>
298 * value from the database
299 * @see #getBytes
300 */
301 public int setBytes(long pos, byte[] bytes)
302 throws SerialException, SQLException {
303 return (setBytes(pos, bytes, 0, bytes.length));
304 }
305
306 /**
307 * Writes all or part of the given <code>byte</code> array to the
308 * <code>BLOB</code> value that this <code>Blob</code> object represents
309 * and returns the number of bytes written.
310 * Writing starts at position <code>pos</code> in the <code>BLOB</code>
311 * value; <i>len</i> bytes from the given byte array are written.
312 *
313 * @param pos the position in the <code>BLOB</code> object at which
314 * to start writing. The first position is <code>1</code>;
315 * must not be less than <code>1</code> nor greater than
316 * the length of this <code>SerialBlob</code> object.
317 * @param bytes the array of bytes to be written to the <code>BLOB</code>
318 * value
319 * @param offset the offset in the <code>byte</code> array at which
320 * to start reading the bytes. The first offset position is
321 * <code>0</code>; must not be less than <code>0</code> nor greater
322 * than the length of the <code>byte</code> array
323 * @param length the number of bytes to be written to the
324 * <code>BLOB</code> value from the array of bytes <i>bytes</i>.
325 *
326 * @return the number of bytes written
327 * @throws SerialException if there is an error accessing the
328 * <code>BLOB</code> value; if an invalid position is set; if an
329 * invalid offset value is set; if number of bytes to be written
330 * is greater than the <code>SerialBlob</code> length; or the combined
331 * values of the length and offset is greater than the Blob buffer
332 * @throws SQLException if there is an error accessing the <code>BLOB</code>
333 * value from the database.
334 * @see #getBytes
335 */
336 public int setBytes(long pos, byte[] bytes, int offset, int length)
337 throws SerialException, SQLException {
338
339 if (offset < 0 || offset > bytes.length) {
340 throw new SerialException("Invalid offset in byte array set");
341 }
342
343 if (pos < 1 || pos > this.length()) {
344 throw new SerialException("Invalid position in BLOB object set");
345 }
346
347 if ((long)(length) > origLen) {
348 throw new SerialException("Buffer is not sufficient to hold the value");
349 }
350
351 if ((length + offset) > bytes.length) {
352 throw new SerialException("Invalid OffSet. Cannot have combined offset " +
353 "and length that is greater that the Blob buffer");
354 }
355
356 int i = 0;
357 pos--; // correct to array indexing
358 while ( i < length || (offset + i +1) < (bytes.length-offset) ) {
359 this.buf[(int)pos + i] = bytes[offset + i ];
360 i++;
361 }
362 return i;
363 }
364
365 /**
366 * Retrieves a stream that can be used to write to the <code>BLOB</code>
367 * value that this <code>Blob</code> object represents. The stream begins
368 * at position <code>pos</code>. This method forwards the
369 * <code>setBinaryStream()</code> call to the underlying <code>Blob</code> in
370 * the event that this <code>SerialBlob</code> object is instantiated with a
371 * <code>Blob</code>. If this <code>SerialBlob</code> is instantiated with
372 * a <code>byte</code> array, a <code>SerialException</code> is thrown.
373 *
374 * @param pos the position in the <code>BLOB</code> value at which
375 * to start writing
376 * @return a <code>java.io.OutputStream</code> object to which data can
377 * be written
378 * @throws SQLException if there is an error accessing the
379 * <code>BLOB</code> value
380 * @throws SerialException if the SerialBlob in not instantiated with a
381 * <code>Blob</code> object that supports <code>setBinaryStream()</code>
382 * @see #getBinaryStream
383 */
384 public java.io.OutputStream setBinaryStream(long pos)
385 throws SerialException, SQLException {
386 if (this.blob != null) {
387 return this.blob.setBinaryStream(pos);
388 } else {
389 throw new SerialException("Unsupported operation. SerialBlob cannot " +
390 "return a writable binary stream, unless instantiated with a Blob object " +
391 "that provides a setBinaryStream() implementation");
392 }
393 }
394
395 /**
396 * Truncates the <code>BLOB</code> value that this <code>Blob</code>
397 * object represents to be <code>len</code> bytes in length.
398 *
399 * @param length the length, in bytes, to which the <code>BLOB</code>
400 * value that this <code>Blob</code> object represents should be
401 * truncated
402 * @throws SerialException if there is an error accessing the Blob value;
403 * or the length to truncate is greater that the SerialBlob length
404 */
405 public void truncate(long length) throws SerialException {
406
407 if (length > len) {
408 throw new SerialException
409 ("Length more than what can be truncated");
410 } else if((int)length == 0) {
411 buf = new byte[0];
412 len = length;
413 } else {
414 len = length;
415 buf = this.getBytes(1, (int)len);
416 }
417 }
418
419
420 /**
421 * Returns an <code>InputStream</code> object that contains a partial <code>Blob</code> value,
422 * starting with the byte specified by pos, which is length bytes in length.
423 *
424 * @param pos the offset to the first byte of the partial value to be retrieved.
425 * The first byte in the <code>Blob</code> is at position 1
426 * @param length the length in bytes of the partial value to be retrieved
427 * @return <code>InputStream</code> through which the partial <code>Blob</code> value can be read.
428 * @throws SQLException if pos is less than 1 or if pos is greater than the number of bytes
429 * in the <code>Blob</code> or if pos + length is greater than the number of bytes
430 * in the <code>Blob</code>
431 *
432 * @since 1.6
433 */
434 public InputStream getBinaryStream(long pos,long length) throws SQLException {
435 throw new java.lang.UnsupportedOperationException("Not supported");
436 }
437
438
439 /**
440 * This method frees the <code>Blob</code> object and releases the resources that it holds.
441 * <code>Blob</code> object. The object is invalid once the <code>free</code>
442 * method is called. If <code>free</code> is called multiple times, the subsequent
443 * calls to <code>free</code> are treated as a no-op.
444 *
445 * @throws SQLException if an error occurs releasing
446 * the Blob's resources
447 * @since 1.6
448 */
449 public void free() throws SQLException {
450 throw new java.lang.UnsupportedOperationException("Not supported");
451 }
452
453 /**
454 * Compares this SerialBlob to the specified object. The result is {@code
455 * true} if and only if the argument is not {@code null} and is a {@code
456 * SerialBlob} object that represents the same sequence of bytes as this
457 * object.
458 *
459 * @param obj The object to compare this {@code SerialBlob} against
460 *
461 * @return {@code true} if the given object represents a {@code SerialBlob}
462 * equivalent to this SerialBlob, {@code false} otherwise
463 *
464 */
465 public boolean equals(Object obj) {
466 if (this == obj) {
467 return true;
468 }
469 if(obj instanceof SerialBlob) {
470 SerialBlob sb = (SerialBlob)obj;
471 if(this.len == sb.len) {
472 return Arrays.equals(buf, sb.buf);
473 }
474 }
475 return false;
476 }
477
478 /**
479 * Returns a hash code for this {@code SerialBlob}.
480 * @return a hash code value for this object.
481 */
482 public int hashCode() {
483 return ((31 +Arrays.hashCode(buf)) * 31 +(int)len) * 31 + (int)origLen;
484 }
485
486 /**
487 * Returns a clone of this {@code SerialBlob}. The copy will contain a
488 * reference to a clone of the internal byte array, not a reference
489 * to the original internal byte array of this {@code SerialBlob} object.
490 * The internal {@code Blob} field will be set to null.
491 *
492 * @return a clone of this SerialBlob
493 */
494 public Object clone() {
495 try {
496 SerialBlob sb = (SerialBlob) super.clone();
497 sb.buf = Arrays.copyOf(buf, (int)len);
498 sb.blob = null;
499 return sb;
500 } catch (CloneNotSupportedException ex) {
501 // this shouldn't happen, since we are Cloneable
502 throw new InternalError();
503 }
504
505 }
506
507 /**
508 * readObject is called to restore the state of the SerialBlob from
509 * a stream.
510 */
511 private void readObject(ObjectInputStream s)
512 throws IOException, ClassNotFoundException {
513
514 ObjectInputStream.GetField fields = s.readFields();
515 byte[] tmp = (byte[])fields.get("buf", null);
516 if (tmp == null)
517 throw new InvalidObjectException("buf is null and should not be!");
518 buf = tmp.clone();
519 len = fields.get("len", 0L);
520 if(buf.length != len)
521 throw new InvalidObjectException("buf is not the expected size");
522 origLen = fields.get("origLen", 0L);
523 blob = (Blob) fields.get("blob", null);
524 }
525
526 /**
527 * writeObject is called to save the state of the SerialBlob
528 * to a stream.
529 */
530 private void writeObject(ObjectOutputStream s)
531 throws IOException, ClassNotFoundException {
532
533 ObjectOutputStream.PutField fields = s.putFields();
534 fields.put("buf", buf);
535 fields.put("len", len);
536 fields.put("origLen", origLen);
537 // Note: this check to see if it is an instance of Serializable
538 // is for backwards compatibiity
539 fields.put("blob", blob instanceof Serializable ? blob : null);
540 s.writeFields();
541 }
542
543 /**
544 * The identifier that assists in the serialization of this <code>SerialBlob</code>
545 * object.
546 */
547
548 static final long serialVersionUID = -8144641928112860441L;
549 }