1 /*
2 * Copyright 2003-2006 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any 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 /**
85 * Constructs a <code>SerialBlob</code> object that is a serialized version of
86 * the given <code>byte</code> array.
87 * <p>
88 * The new <code>SerialBlob</code> object is initialized with the data from the
89 * <code>byte</code> array, thus allowing disconnected <code>RowSet</code>
90 * objects to establish serialized <code>Blob</code> objects without
91 * touching the data source.
92 *
93 * @param b the <code>byte</code> array containing the data for the
94 * <code>Blob</code> object to be serialized
95 * @throws SerialException if an error occurs during serialization
96 * @throws SQLException if a SQL errors occurs
97 */
98 public SerialBlob(byte[] b) throws SerialException, SQLException {
99
100 len = b.length;
101 buf = new byte[(int)len];
102 for(int i = 0; i < len; i++) {
103 buf[i] = b[i];
104 }
105 origLen = len;
106 }
107
108
109 /**
110 * Constructs a <code>SerialBlob</code> object that is a serialized
111 * version of the given <code>Blob</code> object.
112 * <P>
113 * The new <code>SerialBlob</code> object is initialized with the
114 * data from the <code>Blob</code> object; therefore, the
115 * <code>Blob</code> object should have previously brought the
116 * SQL <code>BLOB</code> value's data over to the client from
117 * the database. Otherwise, the new <code>SerialBlob</code> object
118 * will contain no data.
119 *
120 * @param blob the <code>Blob</code> object from which this
121 * <code>SerialBlob</code> object is to be constructed;
122 * cannot be null.
123 * @throws SerialException if an error occurs during serialization
124 * @throws SQLException if the <code>Blob</code> passed to this
125 * to this constructor is a <code>null</code>.
126 * @see java.sql.Blob
127 */
128 public SerialBlob (Blob blob) throws SerialException, SQLException {
129
130 if (blob == null) {
131 throw new SQLException("Cannot instantiate a SerialBlob " +
132 "object with a null Blob object");
133 }
134
135 len = blob.length();
136 buf = blob.getBytes(1, (int)len );
137 this.blob = blob;
138
139 //if ( len < 10240000)
140 // len = 10240000;
141 origLen = len;
142 }
143
144 /**
145 * Copies the specified number of bytes, starting at the given
146 * position, from this <code>SerialBlob</code> object to
147 * another array of bytes.
148 * <P>
149 * Note that if the given number of bytes to be copied is larger than
150 * the length of this <code>SerialBlob</code> object's array of
151 * bytes, the given number will be shortened to the array's length.
152 *
153 * @param pos the ordinal position of the first byte in this
154 * <code>SerialBlob</code> object to be copied;
155 * numbering starts at <code>1</code>; must not be less
156 * than <code>1</code> and must be less than or equal
157 * to the length of this <code>SerialBlob</code> object
158 * @param length the number of bytes to be copied
159 * @return an array of bytes that is a copy of a region of this
160 * <code>SerialBlob</code> object, starting at the given
161 * position and containing the given number of consecutive bytes
162 * @throws SerialException if the given starting position is out of bounds
163 */
164 public byte[] getBytes(long pos, int length) throws SerialException {
165 if (length > len) {
166 length = (int)len;
167 }
168
169 if (pos < 1 || length - pos < 0 ) {
170 throw new SerialException("Invalid arguments: position cannot be less that 1");
171 }
172
173 pos--; // correct pos to array index
174
175 byte[] b = new byte[length];
176
177 for (int i = 0; i < length; i++) {
178 b[i] = this.buf[(int)pos];
179 pos++;
180 }
181 return b;
182 }
183
184 /**
185 * Retrieves the number of bytes in this <code>SerialBlob</code>
186 * object's array of bytes.
187 *
188 * @return a <code>long</code> indicating the length in bytes of this
189 * <code>SerialBlob</code> object's array of bytes
190 * @throws SerialException if an error occurs
191 */
192 public long length() throws SerialException {
193 return len;
194 }
195
196 /**
197 * Returns this <code>SerialBlob</code> object as an input stream.
198 * Unlike the related method, <code>setBinaryStream</code>,
199 * a stream is produced regardless of whether the <code>SerialBlob</code>
200 * was created with a <code>Blob</code> object or a <code>byte</code> array.
201 *
202 * @return a <code>java.io.InputStream</code> object that contains
203 * this <code>SerialBlob</code> object's array of bytes
204 * @throws SerialException if an error occurs
205 * @see #setBinaryStream
206 */
207 public java.io.InputStream getBinaryStream() throws SerialException {
208 InputStream stream = new ByteArrayInputStream(buf);
209 return (java.io.InputStream)stream;
210 }
211
212 /**
213 * Returns the position in this <code>SerialBlob</code> object where
214 * the given pattern of bytes begins, starting the search at the
215 * specified position.
216 *
217 * @param pattern the pattern of bytes for which to search
218 * @param start the position of the byte in this
219 * <code>SerialBlob</code> object from which to begin
220 * the search; the first position is <code>1</code>;
221 * must not be less than <code>1</code> nor greater than
222 * the length of this <code>SerialBlob</code> object
223 * @return the position in this <code>SerialBlob</code> object
224 * where the given pattern begins, starting at the specified
225 * position; <code>-1</code> if the pattern is not found
226 * or the given starting position is out of bounds; position
227 * numbering for the return value starts at <code>1</code>
228 * @throws SerialException if an error occurs when serializing the blob
229 * @throws SQLException if there is an error accessing the <code>BLOB</code>
230 * value from the database
231 */
232 public long position(byte[] pattern, long start)
233 throws SerialException, SQLException {
234 if (start < 1 || start > len) {
235 return -1;
236 }
237
238 int pos = (int)start-1; // internally Blobs are stored as arrays.
239 int i = 0;
240 long patlen = pattern.length;
241
242 while (pos < len) {
243 if (pattern[i] == buf[pos]) {
244 if (i + 1 == patlen) {
245 return (pos + 1) - (patlen - 1);
246 }
247 i++; pos++; // increment pos, and i
248 } else if (pattern[i] != buf[pos]) {
249 pos++; // increment pos only
250 }
251 }
252 return -1; // not found
253 }
254
255 /**
256 * Returns the position in this <code>SerialBlob</code> object where
257 * the given <code>Blob</code> object begins, starting the search at the
258 * specified position.
259 *
260 * @param pattern the <code>Blob</code> object for which to search;
261 * @param start the position of the byte in this
262 * <code>SerialBlob</code> object from which to begin
263 * the search; the first position is <code>1</code>;
264 * must not be less than <code>1</code> nor greater than
265 * the length of this <code>SerialBlob</code> object
266 * @return the position in this <code>SerialBlob</code> object
267 * where the given <code>Blob</code> object begins, starting
268 * at the specified position; <code>-1</code> if the pattern is
269 * not found or the given starting position is out of bounds;
270 * position numbering for the return value starts at <code>1</code>
271 * @throws SerialException if an error occurs when serializing the blob
272 * @throws SQLException if there is an error accessing the <code>BLOB</code>
273 * value from the database
274 */
275 public long position(Blob pattern, long start)
276 throws SerialException, SQLException {
277 return position(pattern.getBytes(1, (int)(pattern.length())), start);
278 }
279
280 /**
281 * Writes the given array of bytes to the <code>BLOB</code> value that
282 * this <code>Blob</code> object represents, starting at position
283 * <code>pos</code>, and returns the number of bytes written.
284 *
285 * @param pos the position in the SQL <code>BLOB</code> value at which
286 * to start writing. The first position is <code>1</code>;
287 * must not be less than <code>1</code> nor greater than
288 * the length of this <code>SerialBlob</code> object.
289 * @param bytes the array of bytes to be written to the <code>BLOB</code>
290 * value that this <code>Blob</code> object represents
291 * @return the number of bytes written
292 * @throws SerialException if there is an error accessing the
293 * <code>BLOB</code> value; or if an invalid position is set; if an
294 * invalid offset value is set
295 * @throws SQLException if there is an error accessing the <code>BLOB</code>
296 * value from the database
297 * @see #getBytes
298 */
299 public int setBytes(long pos, byte[] bytes)
300 throws SerialException, SQLException {
301 return (setBytes(pos, bytes, 0, bytes.length));
302 }
303
304 /**
305 * Writes all or part of the given <code>byte</code> array to the
306 * <code>BLOB</code> value that this <code>Blob</code> object represents
307 * and returns the number of bytes written.
308 * Writing starts at position <code>pos</code> in the <code>BLOB</code>
309 * value; <i>len</i> bytes from the given byte array are written.
310 *
311 * @param pos the position in the <code>BLOB</code> object at which
312 * to start writing. The first position is <code>1</code>;
313 * must not be less than <code>1</code> nor greater than
314 * the length of this <code>SerialBlob</code> object.
315 * @param bytes the array of bytes to be written to the <code>BLOB</code>
316 * value
317 * @param offset the offset in the <code>byte</code> array at which
318 * to start reading the bytes. The first offset position is
319 * <code>0</code>; must not be less than <code>0</code> nor greater
320 * than the length of the <code>byte</code> array
321 * @param length the number of bytes to be written to the
322 * <code>BLOB</code> value from the array of bytes <i>bytes</i>.
323 *
324 * @return the number of bytes written
325 * @throws SerialException if there is an error accessing the
326 * <code>BLOB</code> value; if an invalid position is set; if an
327 * invalid offset value is set; if number of bytes to be written
328 * is greater than the <code>SerialBlob</code> length; or the combined
329 * values of the length and offset is greater than the Blob buffer
330 * @throws SQLException if there is an error accessing the <code>BLOB</code>
331 * value from the database.
332 * @see #getBytes
333 */
334 public int setBytes(long pos, byte[] bytes, int offset, int length)
335 throws SerialException, SQLException {
336
337 if (offset < 0 || offset > bytes.length) {
338 throw new SerialException("Invalid offset in byte array set");
339 }
340
341 if (pos < 1 || pos > this.length()) {
342 throw new SerialException("Invalid position in BLOB object set");
343 }
344
345 if ((long)(length) > origLen) {
346 throw new SerialException("Buffer is not sufficient to hold the value");
347 }
348
349 if ((length + offset) > bytes.length) {
350 throw new SerialException("Invalid OffSet. Cannot have combined offset " +
351 "and length that is greater that the Blob buffer");
352 }
353
354 int i = 0;
355 pos--; // correct to array indexing
356 while ( i < length || (offset + i +1) < (bytes.length-offset) ) {
357 this.buf[(int)pos + i] = bytes[offset + i ];
358 i++;
359 }
360 return i;
361 }
362
363 /**
364 * Retrieves a stream that can be used to write to the <code>BLOB</code>
365 * value that this <code>Blob</code> object represents. The stream begins
366 * at position <code>pos</code>. This method forwards the
367 * <code>setBinaryStream()</code> call to the underlying <code>Blob</code> in
368 * the event that this <code>SerialBlob</code> object is instantiated with a
369 * <code>Blob</code>. If this <code>SerialBlob</code> is instantiated with
370 * a <code>byte</code> array, a <code>SerialException</code> is thrown.
371 *
372 * @param pos the position in the <code>BLOB</code> value at which
373 * to start writing
374 * @return a <code>java.io.OutputStream</code> object to which data can
375 * be written
376 * @throws SQLException if there is an error accessing the
377 * <code>BLOB</code> value
378 * @throws SerialException if the SerialBlob in not instantiated with a
379 * <code>Blob</code> object that supports <code>setBinaryStream()</code>
380 * @see #getBinaryStream
381 */
382 public java.io.OutputStream setBinaryStream(long pos)
383 throws SerialException, SQLException {
384 if (this.blob.setBinaryStream(pos) != null) {
385 return this.blob.setBinaryStream(pos);
386 } else {
387 throw new SerialException("Unsupported operation. SerialBlob cannot " +
388 "return a writable binary stream, unless instantiated with a Blob object " +
389 "that provides a setBinaryStream() implementation");
390 }
391 }
392
393 /**
394 * Truncates the <code>BLOB</code> value that this <code>Blob</code>
395 * object represents to be <code>len</code> bytes in length.
396 *
397 * @param length the length, in bytes, to which the <code>BLOB</code>
398 * value that this <code>Blob</code> object represents should be
399 * truncated
400 * @throws SerialException if there is an error accessing the Blob value;
401 * or the length to truncate is greater that the SerialBlob length
402 */
403 public void truncate(long length) throws SerialException {
404
405 if (length > len) {
406 throw new SerialException
407 ("Length more than what can be truncated");
408 } else if((int)length == 0) {
409 buf = new byte[0];
410 len = length;
411 } else {
412 len = length;
413 buf = this.getBytes(1, (int)len);
414 }
415 }
416
417
418 /**
419 * Returns an <code>InputStream</code> object that contains a partial <code>Blob</code> value,
420 * starting with the byte specified by pos, which is length bytes in length.
421 *
422 * @param pos the offset to the first byte of the partial value to be retrieved.
423 * The first byte in the <code>Blob</code> is at position 1
424 * @param length the length in bytes of the partial value to be retrieved
425 * @return <code>InputStream</code> through which the partial <code>Blob</code> value can be read.
426 * @throws SQLException if pos is less than 1 or if pos is greater than the number of bytes
427 * in the <code>Blob</code> or if pos + length is greater than the number of bytes
428 * in the <code>Blob</code>
429 *
430 * @since 1.6
431 */
432 public InputStream getBinaryStream(long pos,long length) throws SQLException {
433 throw new java.lang.UnsupportedOperationException("Not supported");
434 }
435
436
437 /**
438 * This method frees the <code>Blob</code> object and releases the resources that it holds.
439 * <code>Blob</code> object. The object is invalid once the <code>free</code>
440 * method is called. If <code>free</code> is called multiple times, the subsequent
441 * calls to <code>free</code> are treated as a no-op.
442 *
443 * @throws SQLException if an error occurs releasing
444 * the Blob's resources
445 * @since 1.6
446 */
447 public void free() throws SQLException {
448 throw new java.lang.UnsupportedOperationException("Not supported");
449 }
450 /**
451 * The identifier that assists in the serialization of this <code>SerialBlob</code>
452 * object.
453 */
454
455 static final long serialVersionUID = -8144641928112860441L;
456 }
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