1. /*
  2. * The Apache Software License, Version 1.1
  3. *
  4. *
  5. * Copyright (c) 1999-2002 The Apache Software Foundation. All rights
  6. * reserved.
  7. *
  8. * Redistribution and use in source and binary forms, with or without
  9. * modification, are permitted provided that the following conditions
  10. * are met:
  11. *
  12. * 1. Redistributions of source code must retain the above copyright
  13. * notice, this list of conditions and the following disclaimer.
  14. *
  15. * 2. Redistributions in binary form must reproduce the above copyright
  16. * notice, this list of conditions and the following disclaimer in
  17. * the documentation and/or other materials provided with the
  18. * distribution.
  19. *
  20. * 3. The end-user documentation included with the redistribution,
  21. * if any, must include the following acknowledgment:
  22. * "This product includes software developed by the
  23. * Apache Software Foundation (http://www.apache.org/)."
  24. * Alternately, this acknowledgment may appear in the software itself,
  25. * if and wherever such third-party acknowledgments normally appear.
  26. *
  27. * 4. The names "Xerces" and "Apache Software Foundation" must
  28. * not be used to endorse or promote products derived from this
  29. * software without prior written permission. For written
  30. * permission, please contact apache@apache.org.
  31. *
  32. * 5. Products derived from this software may not be called "Apache",
  33. * nor may "Apache" appear in their name, without prior written
  34. * permission of the Apache Software Foundation.
  35. *
  36. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
  37. * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  38. * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  39. * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
  40. * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  41. * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  42. * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  43. * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  44. * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  45. * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  46. * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  47. * SUCH DAMAGE.
  48. * ====================================================================
  49. *
  50. * This software consists of voluntary contributions made by many
  51. * individuals on behalf of the Apache Software Foundation and was
  52. * originally based on software copyright (c) 2002, International
  53. * Business Machines, Inc., http://www.apache.org. For more
  54. * information on the Apache Software Foundation, please see
  55. * <http://www.apache.org/>.
  56. */
  57. package com.sun.org.apache.xerces.internal.util;
  58. /**
  59. * Shadowed symbol table.
  60. *
  61. * The table has a reference to the main symbol table and is
  62. * not allowed to add new symbols to the main symbol table.
  63. * New symbols are added to the shadow symbol table and are local
  64. * to the component using this table.
  65. *
  66. * @author Andy Clark IBM
  67. * @version $Id: ShadowedSymbolTable.java,v 1.2 2002/08/09 15:18:19 neilg Exp $
  68. */
  69. public final class ShadowedSymbolTable
  70. extends SymbolTable {
  71. //
  72. // Data
  73. //
  74. /** Main symbol table. */
  75. protected SymbolTable fSymbolTable;
  76. //
  77. // Constructors
  78. //
  79. /** Constructs a shadow of the specified symbol table. */
  80. public ShadowedSymbolTable(SymbolTable symbolTable) {
  81. fSymbolTable = symbolTable;
  82. } // <init>(SymbolTable)
  83. //
  84. // SymbolTable methods
  85. //
  86. /**
  87. * Adds the specified symbol to the symbol table and returns a
  88. * reference to the unique symbol. If the symbol already exists,
  89. * the previous symbol reference is returned instead, in order
  90. * guarantee that symbol references remain unique.
  91. *
  92. * @param symbol The new symbol.
  93. */
  94. public String addSymbol(String symbol) {
  95. if (fSymbolTable.containsSymbol(symbol)) {
  96. return fSymbolTable.addSymbol(symbol);
  97. }
  98. return super.addSymbol(symbol);
  99. } // addSymbol(String)
  100. /**
  101. * Adds the specified symbol to the symbol table and returns a
  102. * reference to the unique symbol. If the symbol already exists,
  103. * the previous symbol reference is returned instead, in order
  104. * guarantee that symbol references remain unique.
  105. *
  106. * @param buffer The buffer containing the new symbol.
  107. * @param offset The offset into the buffer of the new symbol.
  108. * @param length The length of the new symbol in the buffer.
  109. */
  110. public String addSymbol(char[] buffer, int offset, int length) {
  111. if (fSymbolTable.containsSymbol(buffer, offset, length)) {
  112. return fSymbolTable.addSymbol(buffer, offset, length);
  113. }
  114. return super.addSymbol(buffer, offset, length);
  115. } // addSymbol(char[],int,int):String
  116. /**
  117. * Returns a hashcode value for the specified symbol. The value
  118. * returned by this method must be identical to the value returned
  119. * by the <code>hash(char[],int,int)</code> method when called
  120. * with the character array that comprises the symbol string.
  121. *
  122. * @param symbol The symbol to hash.
  123. */
  124. public int hash(String symbol) {
  125. return fSymbolTable.hash(symbol);
  126. } // hash(String):int
  127. /**
  128. * Returns a hashcode value for the specified symbol information.
  129. * The value returned by this method must be identical to the value
  130. * returned by the <code>hash(String)</code> method when called
  131. * with the string object created from the symbol information.
  132. *
  133. * @param buffer The character buffer containing the symbol.
  134. * @param offset The offset into the character buffer of the start
  135. * of the symbol.
  136. * @param length The length of the symbol.
  137. */
  138. public int hash(char[] buffer, int offset, int length) {
  139. return fSymbolTable.hash(buffer, offset, length);
  140. } // hash(char[],int,int):int
  141. } // class ShadowedSymbolTable