1. /*
  2. * The Apache Software License, Version 1.1
  3. *
  4. * Copyright (c) 1999 The Apache Software Foundation. All rights
  5. * reserved.
  6. *
  7. * Redistribution and use in source and binary forms, with or without
  8. * modification, are permitted provided that the following conditions
  9. * are met:
  10. *
  11. * 1. Redistributions of source code must retain the above copyright
  12. * notice, this list of conditions and the following disclaimer.
  13. *
  14. * 2. Redistributions in binary form must reproduce the above copyright
  15. * notice, this list of conditions and the following disclaimer in
  16. * the documentation and/or other materials provided with the
  17. * distribution.
  18. *
  19. * 3. The end-user documentation included with the redistribution, if
  20. * any, must include the following acknowlegement:
  21. * "This product includes software developed by the
  22. * Apache Software Foundation (http://www.apache.org/)."
  23. * Alternately, this acknowlegement may appear in the software itself,
  24. * if and wherever such third-party acknowlegements normally appear.
  25. *
  26. * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
  27. * Foundation" must not be used to endorse or promote products derived
  28. * from this software without prior written permission. For written
  29. * permission, please contact apache@apache.org.
  30. *
  31. * 5. Products derived from this software may not be called "Apache"
  32. * nor may "Apache" appear in their names without prior written
  33. * permission of the Apache Group.
  34. *
  35. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
  36. * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  37. * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  38. * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
  39. * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  40. * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  41. * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  42. * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  43. * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  44. * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  45. * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  46. * SUCH DAMAGE.
  47. * ====================================================================
  48. *
  49. * This software consists of voluntary contributions made by many
  50. * individuals on behalf of the Apache Software Foundation. For more
  51. * information on the Apache Software Foundation, please see
  52. * <http://www.apache.org/>.
  53. *
  54. */
  55. package org.apache.commons.el;
  56. import java.util.List;
  57. import java.util.Map;
  58. import javax.servlet.jsp.el.ELException;
  59. import javax.servlet.jsp.el.VariableResolver;
  60. import javax.servlet.jsp.el.FunctionMapper;
  61. /**
  62. *
  63. * <p>Represents a conditional expression. I've decided not to produce an
  64. * abstract base "TernaryOperatorExpression" class since (a) future ternary
  65. * operators are unlikely and (b) it's not clear that there would be a
  66. * meaningful way to abstract them. (For instance, would they all be right-
  67. * associative? Would they all have two fixed operator symbols?)
  68. *
  69. * @author Shawn Bayern
  70. **/
  71. public class ConditionalExpression
  72. extends Expression
  73. {
  74. //-------------------------------------
  75. // Properties
  76. //-------------------------------------
  77. // property condition
  78. Expression mCondition;
  79. public Expression getCondition ()
  80. { return mCondition; }
  81. public void setCondition (Expression pCondition)
  82. { mCondition = pCondition; }
  83. //-------------------------------------
  84. // property trueBranch
  85. Expression mTrueBranch;
  86. public Expression getTrueBranch ()
  87. { return mTrueBranch; }
  88. public void setTrueBranch (Expression pTrueBranch)
  89. { mTrueBranch = pTrueBranch; }
  90. //-------------------------------------
  91. // property falseBranch
  92. Expression mFalseBranch;
  93. public Expression getFalseBranch ()
  94. { return mFalseBranch; }
  95. public void setFalseBranch (Expression pFalseBranch)
  96. { mFalseBranch = pFalseBranch; }
  97. //-------------------------------------
  98. /**
  99. *
  100. * Constructor
  101. **/
  102. public ConditionalExpression (Expression pCondition,
  103. Expression pTrueBranch,
  104. Expression pFalseBranch)
  105. {
  106. mCondition = pCondition;
  107. mTrueBranch = pTrueBranch;
  108. mFalseBranch = pFalseBranch;
  109. }
  110. //-------------------------------------
  111. // Expression methods
  112. //-------------------------------------
  113. /**
  114. *
  115. * Returns the expression in the expression language syntax
  116. **/
  117. public String getExpressionString ()
  118. {
  119. return
  120. "( " + mCondition.getExpressionString() + " ? " +
  121. mTrueBranch.getExpressionString() + " : " +
  122. mFalseBranch.getExpressionString() + " )";
  123. }
  124. //-------------------------------------
  125. /**
  126. *
  127. * Evaluates the conditional expression and returns the literal result
  128. **/
  129. public Object evaluate (VariableResolver vr,
  130. FunctionMapper f,
  131. Logger l)
  132. throws ELException
  133. {
  134. // first, evaluate the condition (and coerce the result to a boolean value)
  135. boolean condition =
  136. Coercions.coerceToBoolean(
  137. mCondition.evaluate(vr, f, l), l).booleanValue();
  138. // then, use this boolean to branch appropriately
  139. if (condition)
  140. return mTrueBranch.evaluate(vr, f, l);
  141. else
  142. return mFalseBranch.evaluate(vr, f, l);
  143. }
  144. //-------------------------------------
  145. }