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 }