1. package com.sun.org.apache.bcel.internal.classfile;
  2. /* ====================================================================
  3. * The Apache Software License, Version 1.1
  4. *
  5. * Copyright (c) 2001 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 "Apache" and "Apache Software Foundation" and
  28. * "Apache BCEL" must not be used to endorse or promote products
  29. * derived from this software without prior written permission. For
  30. * written permission, please contact apache@apache.org.
  31. *
  32. * 5. Products derived from this software may not be called "Apache",
  33. * "Apache BCEL", nor may "Apache" appear in their name, without
  34. * prior written 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. For more
  52. * information on the Apache Software Foundation, please see
  53. * <http://www.apache.org/>.
  54. */
  55. import com.sun.org.apache.bcel.internal.Constants;
  56. import java.io.*;
  57. /**
  58. * This class is derived from <em>Attribute</em> and represents a constant
  59. * value, i.e., a default value for initializing a class field.
  60. * This class is instantiated by the <em>Attribute.readAttribute()</em> method.
  61. *
  62. * @version $Id: ConstantValue.java,v 1.1.1.1 2001/10/29 20:00:00 jvanzyl Exp $
  63. * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
  64. * @see Attribute
  65. */
  66. public final class ConstantValue extends Attribute {
  67. private int constantvalue_index;
  68. /**
  69. * Initialize from another object. Note that both objects use the same
  70. * references (shallow copy). Use clone() for a physical copy.
  71. */
  72. public ConstantValue(ConstantValue c) {
  73. this(c.getNameIndex(), c.getLength(), c.getConstantValueIndex(),
  74. c.getConstantPool());
  75. }
  76. /**
  77. * Construct object from file stream.
  78. * @param name_index Name index in constant pool
  79. * @param length Content length in bytes
  80. * @param file Input stream
  81. * @param constant_pool Array of constants
  82. * @throw IOException
  83. */
  84. ConstantValue(int name_index, int length, DataInputStream file,
  85. ConstantPool constant_pool) throws IOException
  86. {
  87. this(name_index, length, (int)file.readUnsignedShort(), constant_pool);
  88. }
  89. /**
  90. * @param name_index Name index in constant pool
  91. * @param length Content length in bytes
  92. * @param constantvalue_index Index in constant pool
  93. * @param constant_pool Array of constants
  94. */
  95. public ConstantValue(int name_index, int length,
  96. int constantvalue_index,
  97. ConstantPool constant_pool)
  98. {
  99. super(Constants.ATTR_CONSTANT_VALUE, name_index, length, constant_pool);
  100. this.constantvalue_index = constantvalue_index;
  101. }
  102. /**
  103. * Called by objects that are traversing the nodes of the tree implicitely
  104. * defined by the contents of a Java class. I.e., the hierarchy of methods,
  105. * fields, attributes, etc. spawns a tree of objects.
  106. *
  107. * @param v Visitor object
  108. */
  109. public void accept(Visitor v) {
  110. v.visitConstantValue(this);
  111. }
  112. /**
  113. * Dump constant value attribute to file stream on binary format.
  114. *
  115. * @param file Output file stream
  116. * @throw IOException
  117. */
  118. public final void dump(DataOutputStream file) throws IOException
  119. {
  120. super.dump(file);
  121. file.writeShort(constantvalue_index);
  122. }
  123. /**
  124. * @return Index in constant pool of constant value.
  125. */
  126. public final int getConstantValueIndex() { return constantvalue_index; }
  127. /**
  128. * @param constantvalue_index.
  129. */
  130. public final void setConstantValueIndex(int constantvalue_index) {
  131. this.constantvalue_index = constantvalue_index;
  132. }
  133. /**
  134. * @return String representation of constant value.
  135. */
  136. public final String toString() throws InternalError
  137. {
  138. Constant c = constant_pool.getConstant(constantvalue_index);
  139. String buf;
  140. int i;
  141. // Print constant to string depending on its type
  142. switch(c.getTag()) {
  143. case Constants.CONSTANT_Long: buf = "" + ((ConstantLong)c).getBytes(); break;
  144. case Constants.CONSTANT_Float: buf = "" + ((ConstantFloat)c).getBytes(); break;
  145. case Constants.CONSTANT_Double: buf = "" + ((ConstantDouble)c).getBytes(); break;
  146. case Constants.CONSTANT_Integer: buf = "" + ((ConstantInteger)c).getBytes(); break;
  147. case Constants.CONSTANT_String:
  148. i = ((ConstantString)c).getStringIndex();
  149. c = constant_pool.getConstant(i, Constants.CONSTANT_Utf8);
  150. buf = "\"" + convertString(((ConstantUtf8)c).getBytes()) + "\"";
  151. break;
  152. default: throw new InternalError("Type of ConstValue invalid: " + c);
  153. }
  154. return buf;
  155. }
  156. /**
  157. * Escape all occurences of newline chars '\n', quotes \", etc.
  158. */
  159. private static final String convertString(String label) {
  160. char[] ch = label.toCharArray();
  161. StringBuffer buf = new StringBuffer();
  162. for(int i=0; i < ch.length; i++) {
  163. switch(ch[i]) {
  164. case '\n':
  165. buf.append("\\n"); break;
  166. case '\r':
  167. buf.append("\\r"); break;
  168. case '\"':
  169. buf.append("\\\""); break;
  170. case '\'':
  171. buf.append("\\'"); break;
  172. case '\\':
  173. buf.append("\\\\"); break;
  174. default:
  175. buf.append(ch[i]); break;
  176. }
  177. }
  178. return buf.toString();
  179. }
  180. /**
  181. * @return deep copy of this attribute
  182. */
  183. public Attribute copy(ConstantPool constant_pool) {
  184. ConstantValue c = (ConstantValue)clone();
  185. c.constant_pool = constant_pool;
  186. return c;
  187. }
  188. }