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 /**
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 || len - pos < 0 ) {
170 throw new SerialException("Invalid arguments: position cannot be "
171 + "less than 1 or greater than the length of the SerialBlob");
172 }
173
174 pos--; // correct pos to array index
175
176 byte[] b = new byte[length];
177
178 for (int i = 0; i < length; i++) {
179 b[i] = this.buf[(int)pos];
180 pos++;
181 }
182 return b;
183 }
184
185 /**
186 * Retrieves the number of bytes in this <code>SerialBlob</code>
187 * object's array of bytes.
188 *
189 * @return a <code>long</code> indicating the length in bytes of this
190 * <code>SerialBlob</code> object's array of bytes
191 * @throws SerialException if an error occurs
192 */
193 public long length() throws SerialException {
194 return len;
195 }
196
197 /**
198 * Returns this <code>SerialBlob</code> object as an input stream.
199 * Unlike the related method, <code>setBinaryStream</code>,
200 * a stream is produced regardless of whether the <code>SerialBlob</code>
201 * was created with a <code>Blob</code> object or a <code>byte</code> array.
202 *
203 * @return a <code>java.io.InputStream</code> object that contains
204 * this <code>SerialBlob</code> object's array of bytes
205 * @throws SerialException if an error occurs
206 * @see #setBinaryStream
207 */
208 public java.io.InputStream getBinaryStream() throws SerialException {
209 InputStream stream = new ByteArrayInputStream(buf);
210 return stream;
211 }
212
213 /**
214 * Returns the position in this <code>SerialBlob</code> object where
215 * the given pattern of bytes begins, starting the search at the
216 * specified position.
217 *
218 * @param pattern the pattern of bytes for which to search
219 * @param start the position of the byte in this
220 * <code>SerialBlob</code> object from which to begin
221 * the search; the first position is <code>1</code>;
222 * must not be less than <code>1</code> nor greater than
223 * the length of this <code>SerialBlob</code> object
224 * @return the position in this <code>SerialBlob</code> object
225 * where the given pattern begins, starting at the specified
226 * position; <code>-1</code> if the pattern is not found
227 * or the given starting position is out of bounds; position
228 * numbering for the return value starts at <code>1</code>
229 * @throws SerialException if an error occurs when serializing the blob
230 * @throws SQLException if there is an error accessing the <code>BLOB</code>
231 * value from the database
232 */
233 public long position(byte[] pattern, long start)
234 throws SerialException, SQLException {
235 if (start < 1 || start > len) {
236 return -1;
237 }
238
239 int pos = (int)start-1; // internally Blobs are stored as arrays.
240 int i = 0;
241 long patlen = pattern.length;
242
243 while (pos < len) {
244 if (pattern[i] == buf[pos]) {
245 if (i + 1 == patlen) {
246 return (pos + 1) - (patlen - 1);
247 }
248 i++; pos++; // increment pos, and i
249 } else if (pattern[i] != buf[pos]) {
250 pos++; // increment pos only
251 }
252 }
253 return -1; // not found
254 }
255
256 /**
257 * Returns the position in this <code>SerialBlob</code> object where
258 * the given <code>Blob</code> object begins, starting the search at the
259 * specified position.
260 *
261 * @param pattern the <code>Blob</code> object for which to search;
262 * @param start the position of the byte in this
263 * <code>SerialBlob</code> object from which to begin
264 * the search; the first position is <code>1</code>;
265 * must not be less than <code>1</code> nor greater than
266 * the length of this <code>SerialBlob</code> object
267 * @return the position in this <code>SerialBlob</code> object
268 * where the given <code>Blob</code> object begins, starting
269 * at the specified position; <code>-1</code> if the pattern is
270 * not found or the given starting position is out of bounds;
271 * position numbering for the return value starts at <code>1</code>
272 * @throws SerialException if an error occurs when serializing the blob
273 * @throws SQLException if there is an error accessing the <code>BLOB</code>
274 * value from the database
275 */
276 public long position(Blob pattern, long start)
277 throws SerialException, SQLException {
278 return position(pattern.getBytes(1, (int)(pattern.length())), start);
279 }
280
281 /**
282 * Writes the given array of bytes to the <code>BLOB</code> value that
283 * this <code>Blob</code> object represents, starting at position
284 * <code>pos</code>, and returns the number of bytes written.
285 *
286 * @param pos the position in the SQL <code>BLOB</code> value at which
287 * to start writing. The first position is <code>1</code>;
288 * must not be less than <code>1</code> nor greater than
289 * the length of this <code>SerialBlob</code> object.
290 * @param bytes the array of bytes to be written to the <code>BLOB</code>
291 * value that this <code>Blob</code> object represents
292 * @return the number of bytes written
293 * @throws SerialException if there is an error accessing the
294 * <code>BLOB</code> value; or if an invalid position is set; if an
295 * invalid offset value is set
296 * @throws SQLException if there is an error accessing the <code>BLOB</code>
297 * value from the database
298 * @see #getBytes
299 */
300 public int setBytes(long pos, byte[] bytes)
301 throws SerialException, SQLException {
302 return (setBytes(pos, bytes, 0, bytes.length));
303 }
304
305 /**
306 * Writes all or part of the given <code>byte</code> array to the
307 * <code>BLOB</code> value that this <code>Blob</code> object represents
308 * and returns the number of bytes written.
309 * Writing starts at position <code>pos</code> in the <code>BLOB</code>
310 * value; <i>len</i> bytes from the given byte array are written.
311 *
312 * @param pos the position in the <code>BLOB</code> object at which
313 * to start writing. The first position is <code>1</code>;
314 * must not be less than <code>1</code> nor greater than
315 * the length of this <code>SerialBlob</code> object.
316 * @param bytes the array of bytes to be written to the <code>BLOB</code>
317 * value
318 * @param offset the offset in the <code>byte</code> array at which
319 * to start reading the bytes. The first offset position is
320 * <code>0</code>; must not be less than <code>0</code> nor greater
321 * than the length of the <code>byte</code> array
322 * @param length the number of bytes to be written to the
323 * <code>BLOB</code> value from the array of bytes <i>bytes</i>.
324 *
325 * @return the number of bytes written
326 * @throws SerialException if there is an error accessing the
327 * <code>BLOB</code> value; if an invalid position is set; if an
328 * invalid offset value is set; if number of bytes to be written
329 * is greater than the <code>SerialBlob</code> length; or the combined
330 * values of the length and offset is greater than the Blob buffer
331 * @throws SQLException if there is an error accessing the <code>BLOB</code>
332 * value from the database.
333 * @see #getBytes
334 */
335 public int setBytes(long pos, byte[] bytes, int offset, int length)
336 throws SerialException, SQLException {
337
338 if (offset < 0 || offset > bytes.length) {
339 throw new SerialException("Invalid offset in byte array set");
340 }
341
342 if (pos < 1 || pos > this.length()) {
343 throw new SerialException("Invalid position in BLOB object set");
344 }
345
346 if ((long)(length) > origLen) {
347 throw new SerialException("Buffer is not sufficient to hold the value");
348 }
349
350 if ((length + offset) > bytes.length) {
351 throw new SerialException("Invalid OffSet. Cannot have combined offset " +
352 "and length that is greater that the Blob buffer");
353 }
354
355 int i = 0;
356 pos--; // correct to array indexing
357 while ( i < length || (offset + i +1) < (bytes.length-offset) ) {
358 this.buf[(int)pos + i] = bytes[offset + i ];
359 i++;
360 }
361 return i;
362 }
363
364 /**
365 * Retrieves a stream that can be used to write to the <code>BLOB</code>
366 * value that this <code>Blob</code> object represents. The stream begins
367 * at position <code>pos</code>. This method forwards the
368 * <code>setBinaryStream()</code> call to the underlying <code>Blob</code> in
369 * the event that this <code>SerialBlob</code> object is instantiated with a
370 * <code>Blob</code>. If this <code>SerialBlob</code> is instantiated with
371 * a <code>byte</code> array, a <code>SerialException</code> is thrown.
372 *
373 * @param pos the position in the <code>BLOB</code> value at which
374 * to start writing
375 * @return a <code>java.io.OutputStream</code> object to which data can
376 * be written
377 * @throws SQLException if there is an error accessing the
378 * <code>BLOB</code> value
379 * @throws SerialException if the SerialBlob in not instantiated with a
380 * <code>Blob</code> object that supports <code>setBinaryStream()</code>
381 * @see #getBinaryStream
382 */
383 public java.io.OutputStream setBinaryStream(long pos)
384 throws SerialException, SQLException {
385 if (this.blob != null) {
386 return this.blob.setBinaryStream(pos);
387 } else {
388 throw new SerialException("Unsupported operation. SerialBlob cannot " +
389 "return a writable binary stream, unless instantiated with a Blob object " +
390 "that provides a setBinaryStream() implementation");
391 }
392 }
393
394 /**
395 * Truncates the <code>BLOB</code> value that this <code>Blob</code>
396 * object represents to be <code>len</code> bytes in length.
397 *
398 * @param length the length, in bytes, to which the <code>BLOB</code>
399 * value that this <code>Blob</code> object represents should be
400 * truncated
401 * @throws SerialException if there is an error accessing the Blob value;
402 * or the length to truncate is greater that the SerialBlob length
403 */
404 public void truncate(long length) throws SerialException {
405
406 if (length > len) {
407 throw new SerialException
408 ("Length more than what can be truncated");
409 } else if((int)length == 0) {
410 buf = new byte[0];
411 len = length;
412 } else {
413 len = length;
414 buf = this.getBytes(1, (int)len);
415 }
416 }
417
418
419 /**
420 * Returns an <code>InputStream</code> object that contains a partial <code>Blob</code> value,
421 * starting with the byte specified by pos, which is length bytes in length.
422 *
423 * @param pos the offset to the first byte of the partial value to be retrieved.
424 * The first byte in the <code>Blob</code> is at position 1
425 * @param length the length in bytes of the partial value to be retrieved
426 * @return <code>InputStream</code> through which the partial <code>Blob</code> value can be read.
427 * @throws SQLException if pos is less than 1 or if pos is greater than the number of bytes
428 * in the <code>Blob</code> or if pos + length is greater than the number of bytes
429 * in the <code>Blob</code>
430 *
431 * @since 1.6
432 */
433 public InputStream getBinaryStream(long pos,long length) throws SQLException {
434 throw new java.lang.UnsupportedOperationException("Not supported");
435 }
436
437
438 /**
439 * This method frees the <code>Blob</code> object and releases the resources that it holds.
440 * <code>Blob</code> object. The object is invalid once the <code>free</code>
441 * method is called. If <code>free</code> is called multiple times, the subsequent
442 * calls to <code>free</code> are treated as a no-op.
443 *
444 * @throws SQLException if an error occurs releasing
445 * the Blob's resources
446 * @since 1.6
447 */
448 public void free() throws SQLException {
449 throw new java.lang.UnsupportedOperationException("Not supported");
450 }
451 /**
452 * The identifier that assists in the serialization of this <code>SerialBlob</code>
453 * object.
454 */
455
456 static final long serialVersionUID = -8144641928112860441L;
457 }