001: /*
002: * The Apache Software License, Version 1.1
003: *
004: * Copyright (c) 1999 The Apache Software Foundation. All rights
005: * reserved.
006: *
007: * Redistribution and use in source and binary forms, with or without
008: * modification, are permitted provided that the following conditions
009: * are met:
010: *
011: * 1. Redistributions of source code must retain the above copyright
012: * notice, this list of conditions and the following disclaimer.
013: *
014: * 2. Redistributions in binary form must reproduce the above copyright
015: * notice, this list of conditions and the following disclaimer in
016: * the documentation and/or other materials provided with the
017: * distribution.
018: *
019: * 3. The end-user documentation included with the redistribution, if
020: * any, must include the following acknowlegement:
021: * "This product includes software developed by the
022: * Apache Software Foundation (http://www.apache.org/)."
023: * Alternately, this acknowlegement may appear in the software itself,
024: * if and wherever such third-party acknowlegements normally appear.
025: *
026: * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
027: * Foundation" must not be used to endorse or promote products derived
028: * from this software without prior written permission. For written
029: * permission, please contact apache@apache.org.
030: *
031: * 5. Products derived from this software may not be called "Apache"
032: * nor may "Apache" appear in their names without prior written
033: * permission of the Apache Group.
034: *
035: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
036: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
037: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
038: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
039: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
040: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
041: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
042: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
043: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
044: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
045: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
046: * SUCH DAMAGE.
047: * ====================================================================
048: *
049: * This software consists of voluntary contributions made by many
050: * individuals on behalf of the Apache Software Foundation. For more
051: * information on the Apache Software Foundation, please see
052: * <http://www.apache.org/>.
053: *
054: */
055:
056: package org.apache.commons.el;
057:
058: import java.util.List;
059: import java.util.Map;
060: import javax.servlet.jsp.el.ELException;
061: import javax.servlet.jsp.el.VariableResolver;
062: import javax.servlet.jsp.el.FunctionMapper;
063:
064: /**
065: *
066: * <p>An expression representing a binary operator on a value
067: *
068: * @author Nathan Abramson - Art Technology Group
069: * @author Shawn Bayern
070: * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: luehe $
071: **/
072:
073: public class BinaryOperatorExpression extends Expression {
074: //-------------------------------------
075: // Properties
076: //-------------------------------------
077: // property expression
078:
079: Expression mExpression;
080:
081: public Expression getExpression() {
082: return mExpression;
083: }
084:
085: public void setExpression(Expression pExpression) {
086: mExpression = pExpression;
087: }
088:
089: //-------------------------------------
090: // property operators
091:
092: List mOperators;
093:
094: public List getOperators() {
095: return mOperators;
096: }
097:
098: public void setOperators(List pOperators) {
099: mOperators = pOperators;
100: }
101:
102: //-------------------------------------
103: // property expressions
104:
105: List mExpressions;
106:
107: public List getExpressions() {
108: return mExpressions;
109: }
110:
111: public void setExpressions(List pExpressions) {
112: mExpressions = pExpressions;
113: }
114:
115: //-------------------------------------
116: /**
117: *
118: * Constructor
119: **/
120: public BinaryOperatorExpression(Expression pExpression,
121: List pOperators, List pExpressions) {
122: mExpression = pExpression;
123: mOperators = pOperators;
124: mExpressions = pExpressions;
125: }
126:
127: //-------------------------------------
128: // Expression methods
129: //-------------------------------------
130: /**
131: *
132: * Returns the expression in the expression language syntax
133: **/
134: public String getExpressionString() {
135: StringBuffer buf = new StringBuffer();
136: buf.append("(");
137: buf.append(mExpression.getExpressionString());
138: for (int i = 0; i < mOperators.size(); i++) {
139: BinaryOperator operator = (BinaryOperator) mOperators
140: .get(i);
141: Expression expression = (Expression) mExpressions.get(i);
142: buf.append(" ");
143: buf.append(operator.getOperatorSymbol());
144: buf.append(" ");
145: buf.append(expression.getExpressionString());
146: }
147: buf.append(")");
148:
149: return buf.toString();
150: }
151:
152: //-------------------------------------
153: /**
154: *
155: * Evaluates to the literal value
156: **/
157: public Object evaluate(VariableResolver pResolver,
158: FunctionMapper functions, Logger pLogger)
159: throws ELException {
160: Object value = mExpression.evaluate(pResolver, functions,
161: pLogger);
162: for (int i = 0; i < mOperators.size(); i++) {
163: BinaryOperator operator = (BinaryOperator) mOperators
164: .get(i);
165:
166: // For the And/Or operators, we need to coerce to a boolean
167: // before testing if we shouldEvaluate
168: if (operator.shouldCoerceToBoolean()) {
169: value = Coercions.coerceToBoolean(value, pLogger);
170: }
171:
172: if (operator.shouldEvaluate(value)) {
173: Expression expression = (Expression) mExpressions
174: .get(i);
175: Object nextValue = expression.evaluate(pResolver,
176: functions, pLogger);
177:
178: value = operator.apply(value, nextValue, pLogger);
179: }
180: }
181: return value;
182: }
183:
184: //-------------------------------------
185: }
|