1 /* 2 * Copyright (c) 2003, 2014, 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 * <h3> Thread safety </h3> 55 * 56 * <p> A SerialBlob is not safe for use by multiple concurrent threads. If a 57 * SerialBlob is to be used by more than one thread then access to the SerialBlob 58 * should be controlled by appropriate synchronization. 59 * 60 * @author Jonathan Bruce 61 * @since 1.5 62 */ 63 public class SerialBlob implements Blob, Serializable, Cloneable { 64 65 /** 66 * A serialized array of uninterpreted bytes representing the 67 * value of this <code>SerialBlob</code> object. 68 * @serial 69 */ 70 private byte buf[]; 71 72 /** 73 * The internal representation of the <code>Blob</code> object on which this 74 * <code>SerialBlob</code> object is based. 75 */ 76 private Blob blob; 77 78 /** 79 * The number of bytes in this <code>SerialBlob</code> object's 80 * array of bytes. 81 * @serial 82 */ 83 private long len; 84 85 /** 86 * The original number of bytes in this <code>SerialBlob</code> object's 87 * array of bytes when it was first established. 88 * @serial 89 */ 90 private long origLen; 91 92 /** 93 * Constructs a <code>SerialBlob</code> object that is a serialized version of 94 * the given <code>byte</code> array. 95 * <p> 96 * The new <code>SerialBlob</code> object is initialized with the data from the 97 * <code>byte</code> array, thus allowing disconnected <code>RowSet</code> 98 * objects to establish serialized <code>Blob</code> objects without 99 * touching the data source. 100 * 101 * @param b the <code>byte</code> array containing the data for the 102 * <code>Blob</code> object to be serialized 103 * @throws SerialException if an error occurs during serialization 104 * @throws SQLException if a SQL errors occurs 105 */ 106 public SerialBlob(byte[] b) throws SerialException, SQLException { 107 108 len = b.length; 109 buf = new byte[(int)len]; 110 for(int i = 0; i < len; i++) { 111 buf[i] = b[i]; 112 } 113 origLen = len; 114 } 115 116 117 /** 118 * Constructs a <code>SerialBlob</code> object that is a serialized 119 * version of the given <code>Blob</code> object. 120 * <P> 121 * The new <code>SerialBlob</code> object is initialized with the 122 * data from the <code>Blob</code> object; therefore, the 123 * <code>Blob</code> object should have previously brought the 124 * SQL <code>BLOB</code> value's data over to the client from 125 * the database. Otherwise, the new <code>SerialBlob</code> object 126 * will contain no data. 127 * 128 * @param blob the <code>Blob</code> object from which this 129 * <code>SerialBlob</code> object is to be constructed; 130 * cannot be null. 131 * @throws SerialException if an error occurs during serialization 132 * @throws SQLException if the <code>Blob</code> passed to this 133 * to this constructor is a <code>null</code>. 134 * @see java.sql.Blob 135 */ 136 public SerialBlob (Blob blob) throws SerialException, SQLException { 137 138 if (blob == null) { 139 throw new SQLException("Cannot instantiate a SerialBlob " + 140 "object with a null Blob object"); 141 } 142 143 len = blob.length(); 144 buf = blob.getBytes(1, (int)len ); 145 this.blob = blob; 146 147 //if ( len < 10240000) 148 // len = 10240000; 149 origLen = len; 150 } 151 152 /** 153 * Copies the specified number of bytes, starting at the given 154 * position, from this <code>SerialBlob</code> object to 155 * another array of bytes. 156 * <P> 157 * Note that if the given number of bytes to be copied is larger than 158 * the length of this <code>SerialBlob</code> object's array of 159 * bytes, the given number will be shortened to the array's length. 160 * 161 * @param pos the ordinal position of the first byte in this 162 * <code>SerialBlob</code> object to be copied; 163 * numbering starts at <code>1</code>; must not be less 164 * than <code>1</code> and must be less than or equal 165 * to the length of this <code>SerialBlob</code> object 166 * @param length the number of bytes to be copied 167 * @return an array of bytes that is a copy of a region of this 168 * <code>SerialBlob</code> object, starting at the given 169 * position and containing the given number of consecutive bytes 170 * @throws SerialException if the given starting position is out of bounds; 171 * if {@code free} had previously been called on this object 172 */ 173 public byte[] getBytes(long pos, int length) throws SerialException { 174 isValid(); 175 if (length > len) { 176 length = (int)len; 177 } 178 179 if (pos < 1 || len - pos < 0 ) { 180 throw new SerialException("Invalid arguments: position cannot be " 181 + "less than 1 or greater than the length of the SerialBlob"); 182 } 183 184 pos--; // correct pos to array index 185 186 byte[] b = new byte[length]; 187 188 for (int i = 0; i < length; i++) { 189 b[i] = this.buf[(int)pos]; 190 pos++; 191 } 192 return b; 193 } 194 195 /** 196 * Retrieves the number of bytes in this <code>SerialBlob</code> 197 * object's array of bytes. 198 * 199 * @return a <code>long</code> indicating the length in bytes of this 200 * <code>SerialBlob</code> object's array of bytes 201 * @throws SerialException if an error occurs; 202 * if {@code free} had previously been called on this object 203 */ 204 public long length() throws SerialException { 205 isValid(); 206 return len; 207 } 208 209 /** 210 * Returns this <code>SerialBlob</code> object as an input stream. 211 * Unlike the related method, <code>setBinaryStream</code>, 212 * a stream is produced regardless of whether the <code>SerialBlob</code> 213 * was created with a <code>Blob</code> object or a <code>byte</code> array. 214 * 215 * @return a <code>java.io.InputStream</code> object that contains 216 * this <code>SerialBlob</code> object's array of bytes 217 * @throws SerialException if an error occurs; 218 * if {@code free} had previously been called on this object 219 * @see #setBinaryStream 220 */ 221 public java.io.InputStream getBinaryStream() throws SerialException { 222 isValid(); 223 InputStream stream = new ByteArrayInputStream(buf); 224 return stream; 225 } 226 227 /** 228 * Returns the position in this <code>SerialBlob</code> object where 229 * the given pattern of bytes begins, starting the search at the 230 * specified position. 231 * 232 * @param pattern the pattern of bytes for which to search 233 * @param start the position of the byte in this 234 * <code>SerialBlob</code> object from which to begin 235 * the search; the first position is <code>1</code>; 236 * must not be less than <code>1</code> nor greater than 237 * the length of this <code>SerialBlob</code> object 238 * @return the position in this <code>SerialBlob</code> object 239 * where the given pattern begins, starting at the specified 240 * position; <code>-1</code> if the pattern is not found 241 * or the given starting position is out of bounds; position 242 * numbering for the return value starts at <code>1</code> 243 * @throws SerialException if an error occurs when serializing the blob; 244 * if {@code free} had previously been called on this object 245 * @throws SQLException if there is an error accessing the <code>BLOB</code> 246 * value from the database 247 */ 248 public long position(byte[] pattern, long start) 249 throws SerialException, SQLException { 250 isValid(); 251 if (start < 1 || start > len) { 252 return -1; 253 } 254 255 int pos = (int)start-1; // internally Blobs are stored as arrays. 256 int i = 0; 257 long patlen = pattern.length; 258 259 while (pos < len) { 260 if (pattern[i] == buf[pos]) { 261 if (i + 1 == patlen) { 262 return (pos + 1) - (patlen - 1); 263 } 264 i++; pos++; // increment pos, and i 265 } else if (pattern[i] != buf[pos]) { 266 pos++; // increment pos only 267 } 268 } 269 return -1; // not found 270 } 271 272 /** 273 * Returns the position in this <code>SerialBlob</code> object where 274 * the given <code>Blob</code> object begins, starting the search at the 275 * specified position. 276 * 277 * @param pattern the <code>Blob</code> object for which to search; 278 * @param start the position of the byte in this 279 * <code>SerialBlob</code> object from which to begin 280 * the search; the first position is <code>1</code>; 281 * must not be less than <code>1</code> nor greater than 282 * the length of this <code>SerialBlob</code> object 283 * @return the position in this <code>SerialBlob</code> object 284 * where the given <code>Blob</code> object begins, starting 285 * at the specified position; <code>-1</code> if the pattern is 286 * not found or the given starting position is out of bounds; 287 * position numbering for the return value starts at <code>1</code> 288 * @throws SerialException if an error occurs when serializing the blob; 289 * if {@code free} had previously been called on this object 290 * @throws SQLException if there is an error accessing the <code>BLOB</code> 291 * value from the database 292 */ 293 public long position(Blob pattern, long start) 294 throws SerialException, SQLException { 295 isValid(); 296 return position(pattern.getBytes(1, (int)(pattern.length())), start); 297 } 298 299 /** 300 * Writes the given array of bytes to the <code>BLOB</code> value that 301 * this <code>Blob</code> object represents, starting at position 302 * <code>pos</code>, and returns the number of bytes written. 303 * 304 * @param pos the position in the SQL <code>BLOB</code> value at which 305 * to start writing. The first position is <code>1</code>; 306 * must not be less than <code>1</code> nor greater than 307 * the length of this <code>SerialBlob</code> object. 308 * @param bytes the array of bytes to be written to the <code>BLOB</code> 309 * value that this <code>Blob</code> object represents 310 * @return the number of bytes written 311 * @throws SerialException if there is an error accessing the 312 * <code>BLOB</code> value; or if an invalid position is set; if an 313 * invalid offset value is set; 314 * if {@code free} had previously been called on this object 315 * @throws SQLException if there is an error accessing the <code>BLOB</code> 316 * value from the database 317 * @see #getBytes 318 */ 319 public int setBytes(long pos, byte[] bytes) 320 throws SerialException, SQLException { 321 return (setBytes(pos, bytes, 0, bytes.length)); 322 } 323 324 /** 325 * Writes all or part of the given <code>byte</code> array to the 326 * <code>BLOB</code> value that this <code>Blob</code> object represents 327 * and returns the number of bytes written. 328 * Writing starts at position <code>pos</code> in the <code>BLOB</code> 329 * value; <i>len</i> bytes from the given byte array are written. 330 * 331 * @param pos the position in the <code>BLOB</code> object at which 332 * to start writing. The first position is <code>1</code>; 333 * must not be less than <code>1</code> nor greater than 334 * the length of this <code>SerialBlob</code> object. 335 * @param bytes the array of bytes to be written to the <code>BLOB</code> 336 * value 337 * @param offset the offset in the <code>byte</code> array at which 338 * to start reading the bytes. The first offset position is 339 * <code>0</code>; must not be less than <code>0</code> nor greater 340 * than the length of the <code>byte</code> array 341 * @param length the number of bytes to be written to the 342 * <code>BLOB</code> value from the array of bytes <i>bytes</i>. 343 * 344 * @return the number of bytes written 345 * @throws SerialException if there is an error accessing the 346 * <code>BLOB</code> value; if an invalid position is set; if an 347 * invalid offset value is set; if number of bytes to be written 348 * is greater than the <code>SerialBlob</code> length; or the combined 349 * values of the length and offset is greater than the Blob buffer; 350 * if {@code free} had previously been called on this object 351 * @throws SQLException if there is an error accessing the <code>BLOB</code> 352 * value from the database. 353 * @see #getBytes 354 */ 355 public int setBytes(long pos, byte[] bytes, int offset, int length) 356 throws SerialException, SQLException { 357 358 isValid(); 359 if (offset < 0 || offset > bytes.length) { 360 throw new SerialException("Invalid offset in byte array set"); 361 } 362 363 if (pos < 1 || pos > this.length()) { 364 throw new SerialException("Invalid position in BLOB object set"); 365 } 366 367 if ((long)(length) > origLen) { 368 throw new SerialException("Buffer is not sufficient to hold the value"); 369 } 370 371 if ((length + offset) > bytes.length) { 372 throw new SerialException("Invalid OffSet. Cannot have combined offset " + 373 "and length that is greater that the Blob buffer"); 374 } 375 376 int i = 0; 377 pos--; // correct to array indexing 378 while ( i < length || (offset + i +1) < (bytes.length-offset) ) { 379 this.buf[(int)pos + i] = bytes[offset + i ]; 380 i++; 381 } 382 return i; 383 } 384 385 /** 386 * Retrieves a stream that can be used to write to the <code>BLOB</code> 387 * value that this <code>Blob</code> object represents. The stream begins 388 * at position <code>pos</code>. This method forwards the 389 * <code>setBinaryStream()</code> call to the underlying <code>Blob</code> in 390 * the event that this <code>SerialBlob</code> object is instantiated with a 391 * <code>Blob</code>. If this <code>SerialBlob</code> is instantiated with 392 * a <code>byte</code> array, a <code>SerialException</code> is thrown. 393 * 394 * @param pos the position in the <code>BLOB</code> value at which 395 * to start writing 396 * @return a <code>java.io.OutputStream</code> object to which data can 397 * be written 398 * @throws SQLException if there is an error accessing the 399 * <code>BLOB</code> value 400 * @throws SerialException if the SerialBlob in not instantiated with a 401 * <code>Blob</code> object that supports <code>setBinaryStream()</code>; 402 * if {@code free} had previously been called on this object 403 * @see #getBinaryStream 404 */ 405 public java.io.OutputStream setBinaryStream(long pos) 406 throws SerialException, SQLException { 407 isValid(); 408 if (this.blob != null) { 409 return this.blob.setBinaryStream(pos); 410 } else { 411 throw new SerialException("Unsupported operation. SerialBlob cannot " + 412 "return a writable binary stream, unless instantiated with a Blob object " + 413 "that provides a setBinaryStream() implementation"); 414 } 415 } 416 417 /** 418 * Truncates the <code>BLOB</code> value that this <code>Blob</code> 419 * object represents to be <code>len</code> bytes in length. 420 * 421 * @param length the length, in bytes, to which the <code>BLOB</code> 422 * value that this <code>Blob</code> object represents should be 423 * truncated 424 * @throws SerialException if there is an error accessing the Blob value; 425 * or the length to truncate is greater that the SerialBlob length; 426 * if {@code free} had previously been called on this object 427 */ 428 public void truncate(long length) throws SerialException { 429 430 isValid(); 431 if (length > len) { 432 throw new SerialException 433 ("Length more than what can be truncated"); 434 } else if((int)length == 0) { 435 buf = new byte[0]; 436 len = length; 437 } else { 438 len = length; 439 buf = this.getBytes(1, (int)len); 440 } 441 } 442 443 444 /** 445 * Returns an 446 * <code>InputStream</code> object that contains a partial 447 * {@code Blob} value, starting with the byte specified by pos, which is 448 * length bytes in length. 449 * 450 * @param pos the offset to the first byte of the partial value to be 451 * retrieved. The first byte in the {@code Blob} is at position 1 452 * @param length the length in bytes of the partial value to be retrieved 453 * @return 454 * <code>InputStream</code> through which the partial {@code Blob} value can 455 * be read. 456 * @throws SQLException if pos is less than 1 or if pos is greater than the 457 * number of bytes in the {@code Blob} or if pos + length is greater than 458 * the number of bytes in the {@code Blob} 459 * @throws SerialException if the {@code free} method had been previously 460 * called on this object 461 * 462 * @since 1.6 463 */ 464 public InputStream getBinaryStream(long pos, long length) throws SQLException { 465 isValid(); 466 if (pos < 1 || pos > this.length()) { 467 throw new SerialException("Invalid position in BLOB object set"); 468 } 469 if (length < 1 || length > len - pos + 1) { 470 throw new SerialException("length is < 1 or pos + length >" 471 + "total number of bytes"); 472 } 473 return new ByteArrayInputStream(buf, (int) pos - 1, (int) length); 474 } 475 476 477 /** 478 * This method frees the {@code SerialBlob} object and releases the 479 * resources that it holds. The object is invalid once the {@code free} 480 * method is called. <p> If {@code free} is called multiple times, the 481 * subsequent calls to {@code free} are treated as a no-op. </P> 482 * 483 * @throws SQLException if an error occurs releasing the Blob's resources 484 * @since 1.6 485 */ 486 public void free() throws SQLException { 487 if (buf != null) { 488 buf = null; 489 if (blob != null) { 490 blob.free(); 491 } 492 blob = null; 493 } 494 } 495 496 /** 497 * Compares this SerialBlob to the specified object. The result is {@code 498 * true} if and only if the argument is not {@code null} and is a {@code 499 * SerialBlob} object that represents the same sequence of bytes as this 500 * object. 501 * 502 * @param obj The object to compare this {@code SerialBlob} against 503 * 504 * @return {@code true} if the given object represents a {@code SerialBlob} 505 * equivalent to this SerialBlob, {@code false} otherwise 506 * 507 */ 508 public boolean equals(Object obj) { 509 if (this == obj) { 510 return true; 511 } 512 if (obj instanceof SerialBlob) { 513 SerialBlob sb = (SerialBlob)obj; 514 if (this.len == sb.len) { 515 return Arrays.equals(buf, sb.buf); 516 } 517 } 518 return false; 519 } 520 521 /** 522 * Returns a hash code for this {@code SerialBlob}. 523 * @return a hash code value for this object. 524 */ 525 public int hashCode() { 526 return ((31 + Arrays.hashCode(buf)) * 31 + (int)len) * 31 + (int)origLen; 527 } 528 529 /** 530 * Returns a clone of this {@code SerialBlob}. The copy will contain a 531 * reference to a clone of the internal byte array, not a reference 532 * to the original internal byte array of this {@code SerialBlob} object. 533 * The underlying {@code Blob} object will be set to null. 534 * 535 * @return a clone of this SerialBlob 536 */ 537 public Object clone() { 538 try { 539 SerialBlob sb = (SerialBlob) super.clone(); 540 sb.buf = (buf != null) ? Arrays.copyOf(buf, (int)len) : null; 541 sb.blob = null; 542 return sb; 543 } catch (CloneNotSupportedException ex) { 544 // this shouldn't happen, since we are Cloneable 545 throw new InternalError(); 546 } 547 548 } 549 550 /** 551 * readObject is called to restore the state of the SerialBlob from 552 * a stream. 553 */ 554 private void readObject(ObjectInputStream s) 555 throws IOException, ClassNotFoundException { 556 557 ObjectInputStream.GetField fields = s.readFields(); 558 byte[] tmp = (byte[])fields.get("buf", null); 559 if (tmp == null) 560 throw new InvalidObjectException("buf is null and should not be!"); 561 buf = tmp.clone(); 562 len = fields.get("len", 0L); 563 if (buf.length != len) 564 throw new InvalidObjectException("buf is not the expected size"); 565 origLen = fields.get("origLen", 0L); 566 blob = (Blob) fields.get("blob", null); 567 } 568 569 /** 570 * writeObject is called to save the state of the SerialBlob 571 * to a stream. 572 */ 573 private void writeObject(ObjectOutputStream s) 574 throws IOException, ClassNotFoundException { 575 576 ObjectOutputStream.PutField fields = s.putFields(); 577 fields.put("buf", buf); 578 fields.put("len", len); 579 fields.put("origLen", origLen); 580 // Note: this check to see if it is an instance of Serializable 581 // is for backwards compatibiiity 582 fields.put("blob", blob instanceof Serializable ? blob : null); 583 s.writeFields(); 584 } 585 586 /** 587 * Check to see if this object had previously had its {@code free} method 588 * called 589 * 590 * @throws SerialException 591 */ 592 private void isValid() throws SerialException { 593 if (buf == null) { 594 throw new SerialException("Error: You cannot call a method on a " 595 + "SerialBlob instance once free() has been called."); 596 } 597 } 598 599 /** 600 * The identifier that assists in the serialization of this 601 * {@code SerialBlob} object. 602 */ 603 static final long serialVersionUID = -8144641928112860441L; 604 }