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1 /*
2  * The Apache Software License, Version 1.1
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4  * Copyright (c) 1999 The Apache Software Foundation. All rights
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8  * modification, are permitted provided that the following conditions
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12  * notice, this list of conditions and the following disclaimer.
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15  * notice, this list of conditions and the following disclaimer in
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17  * distribution.
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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.
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26  * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
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55
56 package org.apache.commons.el;
57
58 import javax.servlet.jsp.el.ELException JavaDoc;
59
60 /**
61  *
62  * <p>This is the superclass for all binary operators
63  *
64  * @author Nathan Abramson - Art Technology Group
65  * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: luehe $
66  **/
67
68 public abstract class BinaryOperator
69 {
70   //-------------------------------------
71 /**
72    *
73    * Constructor
74    **/
75   public BinaryOperator ()
76   {
77   }
78
79   //-------------------------------------
80 // Expression methods
81 //-------------------------------------
82 /**
83    *
84    * Returns the symbol representing the operator
85    **/
86   public abstract String JavaDoc getOperatorSymbol ();
87
88   //-------------------------------------
89 /**
90    *
91    * Applies the operator to the given pair of values
92    **/
93   public abstract Object JavaDoc apply (Object JavaDoc pLeft,
94                 Object JavaDoc pRight,
95                 Logger pLogger)
96     throws ELException JavaDoc;
97
98   //-------------------------------------
99 /**
100    *
101    * Returns true if evaluation is necessary given the specified Left
102    * value. The And/OrOperators make use of this
103    **/
104   public boolean shouldEvaluate (Object JavaDoc pLeft)
105   {
106     return true;
107   }
108
109   //-------------------------------------
110 /**
111    *
112    * Returns true if the operator expects its arguments to be coerced
113    * to Booleans. The And/Or operators set this to true.
114    **/
115   public boolean shouldCoerceToBoolean ()
116   {
117     return false;
118   }
119
120   //-------------------------------------
121 }
122
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