1/* 2 * Copyright (c) 2003, 2015, 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 26package javax.sql.rowset.serial; 27 28import java.sql.*; 29import java.io.*; 30import java.lang.reflect.*; 31import 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 */ 63public 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) 107 throws SerialException, SQLException { 108 109 len = b.length; 110 buf = new byte[(int)len]; 111 for(int i = 0; i < len; i++) { 112 buf[i] = b[i]; 113 } 114 origLen = len; 115 } 116 117 118 /** 119 * Constructs a <code>SerialBlob</code> object that is a serialized 120 * version of the given <code>Blob</code> object. 121 * <P> 122 * The new <code>SerialBlob</code> object is initialized with the 123 * data from the <code>Blob</code> object; therefore, the 124 * <code>Blob</code> object should have previously brought the 125 * SQL <code>BLOB</code> value's data over to the client from 126 * the database. Otherwise, the new <code>SerialBlob</code> object 127 * will contain no data. 128 * 129 * @param blob the <code>Blob</code> object from which this 130 * <code>SerialBlob</code> object is to be constructed; 131 * cannot be null. 132 * @throws SerialException if an error occurs during serialization 133 * @throws SQLException if the <code>Blob</code> passed to this 134 * to this constructor is a <code>null</code>. 135 * @see java.sql.Blob 136 */ 137 public SerialBlob (Blob blob) 138 throws SerialException, SQLException { 139 140 if (blob == null) { 141 throw new SQLException( 142 "Cannot instantiate a SerialBlob object with a null Blob object"); 143 } 144 145 len = blob.length(); 146 buf = blob.getBytes(1, (int)len ); 147 this.blob = blob; 148 origLen = len; 149 } 150 151 /** 152 * Copies the specified number of bytes, starting at the given 153 * position, from this <code>SerialBlob</code> object to 154 * another array of bytes. 155 * <P> 156 * Note that if the given number of bytes to be copied is larger than 157 * the length of this <code>SerialBlob</code> object's array of 158 * bytes, the given number will be shortened to the array's length. 159 * 160 * @param pos the ordinal position of the first byte in this 161 * <code>SerialBlob</code> object to be copied; 162 * numbering starts at <code>1</code>; must not be less 163 * than <code>1</code> and must be less than or equal 164 * to the length of this <code>SerialBlob</code> object 165 * @param length the number of bytes to be copied 166 * @return an array of bytes that is a copy of a region of this 167 * <code>SerialBlob</code> object, starting at the given 168 * position and containing the given number of consecutive bytes 169 * @throws SerialException if the given starting position is out of bounds; 170 * if {@code free} had previously been called on this object 171 */ 172 public byte[] getBytes(long pos, int length) throws SerialException { 173 isValid(); 174 if (length > len) { 175 length = (int)len; 176 } 177 178 if (pos < 1 || len - pos < 0 ) { 179 throw new SerialException("Invalid arguments: position cannot be " 180 + "less than 1 or greater than the length of the SerialBlob"); 181 } 182 183 pos--; // correct pos to array index 184 185 byte[] b = new byte[length]; 186 187 for (int i = 0; i < length; i++) { 188 b[i] = this.buf[(int)pos]; 189 pos++; 190 } 191 return b; 192 } 193 194 /** 195 * Retrieves the number of bytes in this <code>SerialBlob</code> 196 * object's array of bytes. 197 * 198 * @return a <code>long</code> indicating the length in bytes of this 199 * <code>SerialBlob</code> object's array of bytes 200 * @throws SerialException if an error occurs; 201 * if {@code free} had previously been called on this object 202 */ 203 public long length() throws SerialException { 204 isValid(); 205 return len; 206 } 207 208 /** 209 * Returns this <code>SerialBlob</code> object as an input stream. 210 * Unlike the related method, <code>setBinaryStream</code>, 211 * a stream is produced regardless of whether the <code>SerialBlob</code> 212 * was created with a <code>Blob</code> object or a <code>byte</code> array. 213 * 214 * @return a <code>java.io.InputStream</code> object that contains 215 * this <code>SerialBlob</code> object's array of bytes 216 * @throws SerialException if an error occurs; 217 * if {@code free} had previously been called on this object 218 * @see #setBinaryStream 219 */ 220 public java.io.InputStream getBinaryStream() throws SerialException { 221 isValid(); 222 InputStream stream = new ByteArrayInputStream(buf); 223 return stream; 224 } 225 226 /** 227 * Returns the position in this <code>SerialBlob</code> object where 228 * the given pattern of bytes begins, starting the search at the 229 * specified position. 230 * 231 * @param pattern the pattern of bytes for which to search 232 * @param start the position of the byte in this 233 * <code>SerialBlob</code> object from which to begin 234 * the search; the first position is <code>1</code>; 235 * must not be less than <code>1</code> nor greater than 236 * the length of this <code>SerialBlob</code> object 237 * @return the position in this <code>SerialBlob</code> object 238 * where the given pattern begins, starting at the specified 239 * position; <code>-1</code> if the pattern is not found 240 * or the given starting position is out of bounds; position 241 * numbering for the return value starts at <code>1</code> 242 * @throws SerialException if an error occurs when serializing the blob; 243 * if {@code free} had previously been called on this object 244 * @throws SQLException if there is an error accessing the <code>BLOB</code> 245 * value from the database 246 */ 247 public long position(byte[] pattern, long start) 248 throws SerialException, SQLException { 249 250 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 { 407 408 isValid(); 409 if (this.blob != null) { 410 return this.blob.setBinaryStream(pos); 411 } else { 412 throw new SerialException("Unsupported operation. SerialBlob cannot " + 413 "return a writable binary stream, unless instantiated with a Blob object " + 414 "that provides a setBinaryStream() implementation"); 415 } 416 } 417 418 /** 419 * Truncates the <code>BLOB</code> value that this <code>Blob</code> 420 * object represents to be <code>len</code> bytes in length. 421 * 422 * @param length the length, in bytes, to which the <code>BLOB</code> 423 * value that this <code>Blob</code> object represents should be 424 * truncated 425 * @throws SerialException if there is an error accessing the Blob value; 426 * or the length to truncate is greater that the SerialBlob length; 427 * if {@code free} had previously been called on this object 428 */ 429 public void truncate(long length) throws SerialException { 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( 471 "length is < 1 or pos + length > 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 * readObject is called to restore the state of the SerialBlob from 551 * a stream. 552 */ 553 private void readObject(ObjectInputStream s) 554 throws IOException, ClassNotFoundException { 555 556 ObjectInputStream.GetField fields = s.readFields(); 557 byte[] tmp = (byte[])fields.get("buf", null); 558 if (tmp == null) 559 throw new InvalidObjectException("buf is null and should not be!"); 560 buf = tmp.clone(); 561 len = fields.get("len", 0L); 562 if (buf.length != len) 563 throw new InvalidObjectException("buf is not the expected size"); 564 origLen = fields.get("origLen", 0L); 565 blob = (Blob) fields.get("blob", null); 566 } 567 568 /** 569 * writeObject is called to save the state of the SerialBlob 570 * to a stream. 571 */ 572 private void writeObject(ObjectOutputStream s) 573 throws IOException, ClassNotFoundException { 574 575 ObjectOutputStream.PutField fields = s.putFields(); 576 fields.put("buf", buf); 577 fields.put("len", len); 578 fields.put("origLen", origLen); 579 // Note: this check to see if it is an instance of Serializable 580 // is for backwards compatibility 581 fields.put("blob", blob instanceof Serializable ? blob : null); 582 s.writeFields(); 583 } 584 585 /** 586 * Check to see if this object had previously had its {@code free} method 587 * called 588 * 589 * @throws SerialException 590 */ 591 private void isValid() throws SerialException { 592 if (buf == null) { 593 throw new SerialException("Error: You cannot call a method on a " + 594 "SerialBlob instance once free() has been called."); 595 } 596 } 597 598 /** 599 * The identifier that assists in the serialization of this 600 * {@code SerialBlob} object. 601 */ 602 static final long serialVersionUID = -8144641928112860441L; 603} 604