BinaryOperator


1   /*
2    * Copyright 1999-2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */ 
16  
17  package org.apache.taglibs.standard.lang.jstl;
18  
19  /**
20   *
21   * <p>This is the superclass for all binary operators
22   * 
23   * @author Nathan Abramson - Art Technology Group
24   * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: pierred $
25   **/
26  
27  public abstract class BinaryOperator
28  {
29    //-------------------------------------
30    /**
31     *
32     * Constructor
33     **/
34    public BinaryOperator ()
35    {
36    }
37  
38    //-------------------------------------
39    // Expression methods
40    //-------------------------------------
41    /**
42     *
43     * Returns the symbol representing the operator
44     **/
45    public abstract String   getOperatorSymbol ();
46  
47    //-------------------------------------
48    /**
49     *
50     * Applies the operator to the given pair of values
51     **/
52    public abstract Object   apply (Object   pLeft,
53                  Object   pRight,
54                  Object   pContext,
55                  Logger pLogger)
56      throws ELException;
57  
58    //-------------------------------------
59    /**
60     *
61     * Returns true if evaluation is necessary given the specified Left
62     * value.  The And/OrOperators make use of this
63     **/
64    public boolean shouldEvaluate (Object   pLeft)
65    {
66      return true;
67    }
68  
69    //-------------------------------------
70    /**
71     *
72     * Returns true if the operator expects its arguments to be coerced
73     * to Booleans.  The And/Or operators set this to true.
74     **/
75    public boolean shouldCoerceToBoolean ()
76    {
77      return false;
78    }
79  
80    //-------------------------------------
81  }
82
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