1 /*
2 * Copyright (c) 2003, 2011, 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
32
33 /**
34 * A serialized mapping in the Java programming language of an SQL
35 * <code>BLOB</code> value.
36 * <P>
37 * The <code>SerialBlob</code> class provides a constructor for creating
38 * an instance from a <code>Blob</code> object. Note that the
39 * <code>Blob</code>
40 * object should have brought the SQL <code>BLOB</code> value's data over
41 * to the client before a <code>SerialBlob</code> object
42 * is constructed from it. The data of an SQL <code>BLOB</code> value can
43 * be materialized on the client as an array of bytes (using the method
44 * <code>Blob.getBytes</code>) or as a stream of uninterpreted bytes
45 * (using the method <code>Blob.getBinaryStream</code>).
46 * <P>
47 * <code>SerialBlob</code> methods make it possible to make a copy of a
48 * <code>SerialBlob</code> object as an array of bytes or as a stream.
49 * They also make it possible to locate a given pattern of bytes or a
50 * <code>Blob</code> object within a <code>SerialBlob</code> object
51 * and to update or truncate a <code>Blob</code> object.
52 *
53 * @author Jonathan Bruce
54 */
55 public class SerialBlob implements Blob, Serializable, Cloneable {
56
57 /**
58 * A serialized array of uninterpreted bytes representing the
59 * value of this <code>SerialBlob</code> object.
60 * @serial
61 */
62 private byte buf[];
63
64 /**
65 * The internal representation of the <code>Blob</code> object on which this
66 * <code>SerialBlob</code> object is based.
67 */
68 private Blob blob;
69
70 /**
71 * The number of bytes in this <code>SerialBlob</code> object's
72 * array of bytes.
73 * @serial
74 */
75 private long len;
76
77 /**
78 * The orginal number of bytes in this <code>SerialBlob</code> object's
79 * array of bytes when it was first established.
80 * @serial
81 */
82 private long origLen;
83
84 private boolean isFree = false;
85
86 /**
87 * Constructs a <code>SerialBlob</code> object that is a serialized version of
88 * the given <code>byte</code> array.
89 * <p>
90 * The new <code>SerialBlob</code> object is initialized with the data from the
91 * <code>byte</code> array, thus allowing disconnected <code>RowSet</code>
92 * objects to establish serialized <code>Blob</code> objects without
93 * touching the data source.
94 *
95 * @param b the <code>byte</code> array containing the data for the
96 * <code>Blob</code> object to be serialized
97 * @throws SerialException if an error occurs during serialization
98 * @throws SQLException if a SQL errors occurs
99 */
100 public SerialBlob(byte[] b) throws SerialException, SQLException {
101
102 len = b.length;
103 buf = new byte[(int)len];
104 for(int i = 0; i < len; i++) {
105 buf[i] = b[i];
106 }
107 origLen = len;
108 }
109
110
111 /**
112 * Constructs a <code>SerialBlob</code> object that is a serialized
113 * version of the given <code>Blob</code> object.
114 * <P>
115 * The new <code>SerialBlob</code> object is initialized with the
116 * data from the <code>Blob</code> object; therefore, the
117 * <code>Blob</code> object should have previously brought the
118 * SQL <code>BLOB</code> value's data over to the client from
119 * the database. Otherwise, the new <code>SerialBlob</code> object
120 * will contain no data.
121 *
122 * @param blob the <code>Blob</code> object from which this
123 * <code>SerialBlob</code> object is to be constructed;
124 * cannot be null.
125 * @throws SerialException if an error occurs during serialization
126 * @throws SQLException if the <code>Blob</code> passed to this
127 * to this constructor is a <code>null</code>.
128 * @see java.sql.Blob
129 */
130 public SerialBlob (Blob blob) throws SerialException, SQLException {
131
132 if (blob == null) {
133 throw new SQLException("Cannot instantiate a SerialBlob " +
134 "object with a null Blob object");
135 }
136
137 len = blob.length();
138 buf = blob.getBytes(1, (int)len );
139 this.blob = blob;
140
141 //if ( len < 10240000)
142 // len = 10240000;
143 origLen = len;
144 }
145
146 /**
147 * Copies the specified number of bytes, starting at the given
148 * position, from this <code>SerialBlob</code> object to
149 * another array of bytes.
150 * <P>
151 * Note that if the given number of bytes to be copied is larger than
152 * the length of this <code>SerialBlob</code> object's array of
153 * bytes, the given number will be shortened to the array's length.
154 *
155 * @param pos the ordinal position of the first byte in this
156 * <code>SerialBlob</code> object to be copied;
157 * numbering starts at <code>1</code>; must not be less
158 * than <code>1</code> and must be less than or equal
159 * to the length of this <code>SerialBlob</code> object
160 * @param length the number of bytes to be copied
161 * @return an array of bytes that is a copy of a region of this
162 * <code>SerialBlob</code> object, starting at the given
163 * position and containing the given number of consecutive bytes
164 * @throws SerialException if the given starting position is out of bounds
165 * or called after free() has been called.
166 */
167 public byte[] getBytes(long pos, int length) throws SerialException {
168 isFreed();
169
170 if (length > len) {
171 length = (int)len;
172 }
173
174 if (pos < 1 || len - pos < 0 ) {
175 throw new SerialException("Invalid arguments: position cannot be "
176 + "less than 1 or greater than the length of the SerialBlob");
177 }
178
179 pos--; // correct pos to array index
180
181 byte[] b = new byte[length];
182
183 for (int i = 0; i < length; i++) {
184 b[i] = this.buf[(int)pos];
185 pos++;
186 }
187 return b;
188 }
189
190 /**
191 * Retrieves the number of bytes in this <code>SerialBlob</code>
192 * object's array of bytes.
193 *
194 * @return a <code>long</code> indicating the length in bytes of this
195 * <code>SerialBlob</code> object's array of bytes
196 * @throws SerialException if an error occurs or called after free() has been called.
197 */
198 public long length() throws SerialException {
199 isFreed();
200 return len;
201 }
202
203 /**
204 * Returns this <code>SerialBlob</code> object as an input stream.
205 * Unlike the related method, <code>setBinaryStream</code>,
206 * a stream is produced regardless of whether the <code>SerialBlob</code>
207 * was created with a <code>Blob</code> object or a <code>byte</code> array.
208 *
209 * @return a <code>java.io.InputStream</code> object that contains
210 * this <code>SerialBlob</code> object's array of bytes
211 * @throws SerialException if an error occurs or called after free() has
212 * been called.
213 * @see #setBinaryStream
214 */
215 public java.io.InputStream getBinaryStream() throws SerialException {
216 isFreed();
217
218 InputStream stream = new ByteArrayInputStream(buf);
219 return stream;
220 }
221
222 /**
223 * Returns the position in this <code>SerialBlob</code> object where
224 * the given pattern of bytes begins, starting the search at the
225 * specified position.
226 *
227 * @param pattern the pattern of bytes for which to search
228 * @param start the position of the byte in this
229 * <code>SerialBlob</code> object from which to begin
230 * the search; the first position is <code>1</code>;
231 * must not be less than <code>1</code> nor greater than
232 * the length of this <code>SerialBlob</code> object
233 * @return the position in this <code>SerialBlob</code> object
234 * where the given pattern begins, starting at the specified
235 * position; <code>-1</code> if the pattern is not found
236 * or the given starting position is out of bounds; position
237 * numbering for the return value starts at <code>1</code>
238 * @throws SerialException if an error occurs when serializing the blob or
239 * called after free() has been called.
240 * @throws SQLException if there is an error accessing the <code>BLOB</code>
241 * value from the database
242 */
243 public long position(byte[] pattern, long start)
244 throws SerialException, SQLException {
245 isFreed();
246
247 if (start < 1 || start > len) {
248 return -1;
249 }
250
251 int pos = (int)start-1; // internally Blobs are stored as arrays.
252 int i = 0;
253 long patlen = pattern.length;
254
255 while (pos < len) {
256 if (pattern[i] == buf[pos]) {
257 if (i + 1 == patlen) {
258 return (pos + 1) - (patlen - 1);
259 }
260 i++; pos++; // increment pos, and i
261 } else if (pattern[i] != buf[pos]) {
262 pos++; // increment pos only
263 }
264 }
265 return -1; // not found
266 }
267
268 /**
269 * Returns the position in this <code>SerialBlob</code> object where
270 * the given <code>Blob</code> object begins, starting the search at the
271 * specified position.
272 *
273 * @param pattern the <code>Blob</code> object for which to search;
274 * @param start the position of the byte in this
275 * <code>SerialBlob</code> object from which to begin
276 * the search; the first position is <code>1</code>;
277 * must not be less than <code>1</code> nor greater than
278 * the length of this <code>SerialBlob</code> object
279 * @return the position in this <code>SerialBlob</code> object
280 * where the given <code>Blob</code> object begins, starting
281 * at the specified position; <code>-1</code> if the pattern is
282 * not found or the given starting position is out of bounds;
283 * position numbering for the return value starts at <code>1</code>
284 * @throws SerialException if an error occurs when serializing the blob or
285 * called after free() has been called.
286 * @throws SQLException if there is an error accessing the <code>BLOB</code>
287 * value from the database
288 */
289 public long position(Blob pattern, long start)
290 throws SerialException, SQLException {
291 isFreed();
292 return position(pattern.getBytes(1, (int)(pattern.length())), start);
293 }
294
295 /**
296 * Writes the given array of bytes to the <code>BLOB</code> value that
297 * this <code>Blob</code> object represents, starting at position
298 * <code>pos</code>, and returns the number of bytes written.
299 *
300 * @param pos the position in the SQL <code>BLOB</code> value at which
301 * to start writing. The first position is <code>1</code>;
302 * must not be less than <code>1</code> nor greater than
303 * the length of this <code>SerialBlob</code> object.
304 * @param bytes the array of bytes to be written to the <code>BLOB</code>
305 * value that this <code>Blob</code> object represents
306 * @return the number of bytes written
307 * @throws SerialException if there is an error accessing the
308 * <code>BLOB</code> value; or if an invalid position is set; if an
309 * invalid offset value is set or called after free() has been called.
310 * @throws SQLException if there is an error accessing the <code>BLOB</code>
311 * value from the database
312 * @see #getBytes
313 */
314 public int setBytes(long pos, byte[] bytes)
315 throws SerialException, SQLException {
316 isFreed();
317 return (setBytes(pos, bytes, 0, bytes.length));
318 }
319
320 /**
321 * Writes all or part of the given <code>byte</code> array to the
322 * <code>BLOB</code> value that this <code>Blob</code> object represents
323 * and returns the number of bytes written.
324 * Writing starts at position <code>pos</code> in the <code>BLOB</code>
325 * value; <i>len</i> bytes from the given byte array are written.
326 *
327 * @param pos the position in the <code>BLOB</code> object at which
328 * to start writing. The first position is <code>1</code>;
329 * must not be less than <code>1</code> nor greater than
330 * the length of this <code>SerialBlob</code> object.
331 * @param bytes the array of bytes to be written to the <code>BLOB</code>
332 * value
333 * @param offset the offset in the <code>byte</code> array at which
334 * to start reading the bytes. The first offset position is
335 * <code>0</code>; must not be less than <code>0</code> nor greater
336 * than the length of the <code>byte</code> array
337 * @param length the number of bytes to be written to the
338 * <code>BLOB</code> value from the array of bytes <i>bytes</i>.
339 *
340 * @return the number of bytes written
341 * @throws SerialException if there is an error accessing the
342 * <code>BLOB</code> value; if an invalid position is set; if an
343 * invalid offset value is set; if number of bytes to be written
344 * is greater than the <code>SerialBlob</code> length; or the combined
345 * values of the length and offset is greater than the Blob buffer or
346 * called after free() has been called.
347 * @throws SQLException if there is an error accessing the <code>BLOB</code>
348 * value from the database.
349 * @see #getBytes
350 */
351 public int setBytes(long pos, byte[] bytes, int offset, int length)
352 throws SerialException, SQLException {
353 isFreed();
354
355 if (offset < 0 || offset > bytes.length) {
356 throw new SerialException("Invalid offset in byte array set");
357 }
358
359 if (pos < 1 || pos > this.length()) {
360 throw new SerialException("Invalid position in BLOB object set");
361 }
362
363 if ((long)(length) > origLen) {
364 throw new SerialException("Buffer is not sufficient to hold the value");
365 }
366
367 if ((length + offset) > bytes.length) {
368 throw new SerialException("Invalid OffSet. Cannot have combined offset " +
369 "and length that is greater that the Blob buffer");
370 }
371
372 int i = 0;
373 pos--; // correct to array indexing
374 while ( i < length || (offset + i +1) < (bytes.length-offset) ) {
375 this.buf[(int)pos + i] = bytes[offset + i ];
376 i++;
377 }
378 return i;
379 }
380
381 /**
382 * Retrieves a stream that can be used to write to the <code>BLOB</code>
383 * value that this <code>Blob</code> object represents. The stream begins
384 * at position <code>pos</code>. This method forwards the
385 * <code>setBinaryStream()</code> call to the underlying <code>Blob</code> in
386 * the event that this <code>SerialBlob</code> object is instantiated with a
387 * <code>Blob</code>. If this <code>SerialBlob</code> is instantiated with
388 * a <code>byte</code> array, a <code>SerialException</code> is thrown.
389 *
390 * @param pos the position in the <code>BLOB</code> value at which
391 * to start writing
392 * @return a <code>java.io.OutputStream</code> object to which data can
393 * be written
394 * @throws SQLException if there is an error accessing the
395 * <code>BLOB</code> value
396 * @throws SerialException if the SerialBlob in not instantiated with a
397 * <code>Blob</code> object that supports <code>setBinaryStream()</code>
398 * or called after free() has been called.
399 * @see #getBinaryStream
400 */
401 public java.io.OutputStream setBinaryStream(long pos)
402 throws SerialException, SQLException {
403 isFreed();
404
405 if (this.blob != null) {
406 return this.blob.setBinaryStream(pos);
407 } else {
408 throw new SerialException("Unsupported operation. SerialBlob cannot " +
409 "return a writable binary stream, unless instantiated with a Blob object " +
410 "that provides a setBinaryStream() implementation");
411 }
412 }
413
414 /**
415 * Truncates the <code>BLOB</code> value that this <code>Blob</code>
416 * object represents to be <code>len</code> bytes in length.
417 *
418 * @param length the length, in bytes, to which the <code>BLOB</code>
419 * value that this <code>Blob</code> object represents should be
420 * truncated
421 * @throws SerialException if there is an error accessing the Blob value;
422 * or the length to truncate is greater that the SerialBlob length or
423 * called after free() has been called.
424 */
425 public void truncate(long length) throws SerialException {
426 isFreed();
427
428 if (length > len) {
429 throw new SerialException
430 ("Length more than what can be truncated");
431 } else if((int)length == 0) {
432 buf = new byte[0];
433 len = length;
434 } else {
435 len = length;
436 buf = this.getBytes(1, (int)len);
437 }
438 }
439
440
441 /**
442 * Returns an <code>InputStream</code> object that contains a partial <code>Blob</code> value,
443 * starting with the byte specified by pos, which is length bytes in length.
444 *
445 * @param pos the offset to the first byte of the partial value to be retrieved.
446 * The first byte in the <code>Blob</code> is at position 1
447 * @param length the length in bytes of the partial value to be retrieved
448 * @return <code>InputStream</code> through which the partial <code>Blob</code> value can be read.
449 * @throws SerialException if called after free() has been called.
450 * @throws SQLException if pos is less than 1 or if pos is greater than the number of bytes
451 * in the <code>Blob</code> or if pos + length is greater than the number of bytes
452 * in the <code>Blob</code>
453 *
454 * @since 1.6
455 */
456 public InputStream getBinaryStream(long pos,long length) throws SerialException, SQLException {
457 isFreed();
458
459 if (pos < 1 || pos > len) {
460 throw new SerialException("Invalid pos in getBinaryStream");
461 }
462 if ((pos - 1) + length > len) {
463 throw new SerialException(
464 "pos + length greater than total number of bytes");
465 }
466 return new ByteArrayInputStream(buf, (int) pos - 1, (int) length);
467 }
468
469
470 /**
471 * This method frees the <code>Blob</code> object and releases the
472 * resources that it holds. <code>Blob</code> object. The object is
473 * invalid once the <code>free</code> method is called. After
474 * <code>free</code> has been called, any attempt to invoke a method
475 * other than <code>free</code> will result in a
476 * <code>SerialException</code> being thrown. If <code>free</code> is
477 * called multiple times, the subsequent calls to <code>free</code>
478 * are treated as a no-op.
479 *
480 * @throws SQLException if an error occurs releasing the Blob's resources
481 * @since 1.6
482 */
483 public void free() throws SQLException {
484 if (isFree == false) {
485 len = -1;
486 origLen = -1;
487 buf = null;
488
489 if (blob != null) {
490 blob.free();
491 blob = null;
492 }
493
494 isFree = true;
495 }
496 }
497
498 private void isFreed() throws SerialException {
499 if (isFree == true) {
500 throw new SerialException(
501 "Unsupported operation. SerialBlob cannot "
502 + "execute this operation when it"
503 + "has already been freed by free()");
504 }
505 }
506
507 /**
508 * The identifier that assists in the serialization of this <code>SerialBlob</code>
509 * object.
510 */
511
512 static final long serialVersionUID = -8144641928112860441L;
513 }