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Java > Open Source Codes > org > apache > commons > el > UnaryOperatorExpression


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55
56 package org.apache.commons.el;
57
58 import java.util.List JavaDoc;
59 import javax.servlet.jsp.el.ELException JavaDoc;
60 import javax.servlet.jsp.el.VariableResolver JavaDoc;
61 import javax.servlet.jsp.el.FunctionMapper JavaDoc;
62
63 /**
64  *
65  * <p>An expression representing one or more unary operators on a
66  * value
67  *
68  * @author Nathan Abramson - Art Technology Group
69  * @author Shawn Bayern
70  * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: luehe $
71  **/

72
73 public class UnaryOperatorExpression
74   extends Expression
75 {
76   //-------------------------------------
77
// Properties
78
//-------------------------------------
79
// property operator
80

81   UnaryOperator mOperator;
82   public UnaryOperator getOperator ()
83   { return mOperator; }
84   public void setOperator (UnaryOperator pOperator)
85   { mOperator = pOperator; }
86
87   //-------------------------------------
88
// property operators
89

90   List JavaDoc mOperators;
91   public List JavaDoc getOperators ()
92   { return mOperators; }
93   public void setOperators (List JavaDoc pOperators)
94   { mOperators = pOperators; }
95
96   //-------------------------------------
97
// property expression
98

99   Expression mExpression;
100   public Expression getExpression ()
101   { return mExpression; }
102   public void setExpression (Expression pExpression)
103   { mExpression = pExpression; }
104
105   //-------------------------------------
106
/**
107    *
108    * Constructor
109    **/

110   public UnaryOperatorExpression (UnaryOperator pOperator,
111                   List JavaDoc pOperators,
112                   Expression pExpression)
113   {
114     mOperator = pOperator;
115     mOperators = pOperators;
116     mExpression = pExpression;
117   }
118
119   //-------------------------------------
120
// Expression methods
121
//-------------------------------------
122
/**
123    *
124    * Returns the expression in the expression language syntax
125    **/

126   public String JavaDoc getExpressionString ()
127   {
128     StringBuffer JavaDoc buf = new StringBuffer JavaDoc ();
129     buf.append ("(");
130     if (mOperator != null) {
131       buf.append (mOperator.getOperatorSymbol ());
132       buf.append (" ");
133     }
134     else {
135       for (int i = 0; i < mOperators.size (); i++) {
136     UnaryOperator operator = (UnaryOperator) mOperators.get (i);
137     buf.append (operator.getOperatorSymbol ());
138     buf.append (" ");
139       }
140     }
141     buf.append (mExpression.getExpressionString ());
142     buf.append (")");
143     return buf.toString ();
144   }
145
146   //-------------------------------------
147
/**
148    *
149    * Evaluates to the literal value
150    **/

151   public Object JavaDoc evaluate (VariableResolver JavaDoc pResolver,
152               FunctionMapper JavaDoc functions,
153               Logger pLogger)
154     throws ELException JavaDoc
155   {
156     Object JavaDoc value = mExpression.evaluate (pResolver, functions, pLogger);
157     if (mOperator != null) {
158       value = mOperator.apply (value, pLogger);
159     }
160     else {
161       for (int i = mOperators.size () - 1; i >= 0; i--) {
162     UnaryOperator operator = (UnaryOperator) mOperators.get (i);
163     value = operator.apply (value, pLogger);
164       }
165     }
166     return value;
167   }
168
169   //-------------------------------------
170
}
171
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