1. /*
  2. * The Apache Software License, Version 1.1
  3. *
  4. *
  5. * Copyright (c) 1999,2000 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) 1999, 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 org.apache.xml.dtm.ref;
  58. import java.util.Vector;
  59. import java.util.Hashtable;
  60. /** <p>CustomStringPool is an example of appliction provided data structure
  61. * for a DTM implementation to hold symbol references, e.g. elelment names.
  62. * It will follow the DTMDStringPool interface and use two simple methods
  63. * indexToString(int i) and stringToIndex(Sring s) to map between a set of
  64. * string values and a set of integer index values. Therefore, an application
  65. * may improve DTM processing speed by substituting the DTM symbol resolution
  66. * tables with application specific quick symbol resolution tables.</p>
  67. *
  68. * %REVIEW% The only difference between this an DTMStringPool seems to be that
  69. * it uses a java.lang.Hashtable full of Integers rather than implementing its
  70. * own hashing. Joe deliberately avoided that approach when writing
  71. * DTMStringPool, since it is both much more memory-hungry and probably slower
  72. * -- especially in JDK 1.1.x, where Hashtable is synchronized. We need to
  73. * either justify this implementation or discard it.
  74. *
  75. * <p>Status: In progress, under discussion.</p>
  76. * */
  77. public class CustomStringPool extends DTMStringPool {
  78. //final Vector m_intToString;
  79. //static final int HASHPRIME=101;
  80. //int[] m_hashStart=new int[HASHPRIME];
  81. final Hashtable m_stringToInt = new Hashtable();
  82. public static final int NULL=-1;
  83. public CustomStringPool()
  84. {
  85. super();
  86. /*m_intToString=new Vector();
  87. System.out.println("In constructor m_intToString is " +
  88. ((null == m_intToString) ? "null" : "not null"));*/
  89. //m_stringToInt=new Hashtable();
  90. //removeAllElements();
  91. }
  92. public void removeAllElements()
  93. {
  94. m_intToString.removeAllElements();
  95. if (m_stringToInt != null)
  96. m_stringToInt.clear();
  97. }
  98. /** @return string whose value is uniquely identified by this integer index.
  99. * @throws java.lang.ArrayIndexOutOfBoundsException
  100. * if index doesn't map to a string.
  101. * */
  102. public String indexToString(int i)
  103. throws java.lang.ArrayIndexOutOfBoundsException
  104. {
  105. return(String) m_intToString.elementAt(i);
  106. }
  107. /** @return integer index uniquely identifying the value of this string. */
  108. public int stringToIndex(String s)
  109. {
  110. if (s==null) return NULL;
  111. Integer iobj=(Integer)m_stringToInt.get(s);
  112. if (iobj==null) {
  113. m_intToString.addElement(s);
  114. iobj=new Integer(m_intToString.size());
  115. m_stringToInt.put(s,iobj);
  116. }
  117. return iobj.intValue();
  118. }
  119. }