1 /*
2 * $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/java/org/apache/commons/jelly/expression/jexl/JexlExpression.java,v 1.9 2002/07/22 14:34:09 jstrachan Exp $
3 * $Revision: 1.9 $
4 * $Date: 2002/07/22 14:34:09 $
5 *
6 * ====================================================================
7 *
8 * The Apache Software License, Version 1.1
9 *
10 * Copyright (c) 1999-2002 The Apache Software Foundation. All rights
11 * reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 *
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 *
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in
22 * the documentation and/or other materials provided with the
23 * distribution.
24 *
25 * 3. The end-user documentation included with the redistribution, if
26 * any, must include the following acknowlegement:
27 * "This product includes software developed by the
28 * Apache Software Foundation (http://www.apache.org/)."
29 * Alternately, this acknowlegement may appear in the software itself,
30 * if and wherever such third-party acknowlegements normally appear.
31 *
32 * 4. The names "The Jakarta Project", "Commons", and "Apache Software
33 * Foundation" must not be used to endorse or promote products derived
34 * from this software without prior written permission. For written
35 * permission, please contact apache@apache.org.
36 *
37 * 5. Products derived from this software may not be called "Apache"
38 * nor may "Apache" appear in their names without prior written
39 * permission of the Apache Group.
40 *
41 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
42 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
43 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
44 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
45 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
47 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
48 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
49 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
50 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
51 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52 * SUCH DAMAGE.
53 * ====================================================================
54 *
55 * This software consists of voluntary contributions made by many
56 * individuals on behalf of the Apache Software Foundation. For more
57 * information on the Apache Software Foundation, please see
58 * <http://www.apache.org/>.
59 *
60 * $Id: JexlExpression.java,v 1.9 2002/07/22 14:34:09 jstrachan Exp $
61 */
62
63 package org.apache.commons.jelly.expression.jexl;
64
65 import java.util.Map;
66 import java.util.Set;
67 import java.util.Collection;
68
69 import org.apache.commons.jelly.JellyContext;
70 import org.apache.commons.jelly.expression.ExpressionSupport;
71
72 import org.apache.commons.jexl.Expression;
73 import org.apache.commons.jexl.JexlContext;
74
75 import org.apache.commons.logging.Log;
76 import org.apache.commons.logging.LogFactory;
77
78 /***
79 * Represents a <a href="http://jakarta.apache.org/commons/jexl.html">Jexl</a>
80 * expression which fully supports the Expression Language in JSTL and JSP
81 * along with some extra features like object method invocation.
82 *
83 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
84 * @version $Revision: 1.9 $
85 */
86
87 public class JexlExpression extends ExpressionSupport {
88
89 /*** The Log to which logging calls will be made. */
90 private static final Log log = LogFactory.getLog(JexlExpression.class);
91
92 /*** The Jexl expression object */
93 private Expression expression;
94
95 public JexlExpression(Expression expression) {
96 this.expression = expression;
97 }
98
99 // Expression interface
100 //-------------------------------------------------------------------------
101 public Object evaluate(JellyContext context) {
102 try {
103 JexlContext jexlContext = new JellyJexlContext( context );
104 if (log.isDebugEnabled()) {
105 log.debug("Evaluating EL: " + expression);
106 }
107 return expression.evaluate(jexlContext);
108 }
109 catch (Exception e) {
110 log.warn("Caught exception evaluating: " + expression + ". Reason: " + e, e);
111 return null;
112 }
113 }
114 }
115
116 class JellyJexlContext implements JexlContext {
117
118 private Map vars;
119
120 JellyJexlContext(JellyContext context) {
121 this.vars = new JellyMap( context );
122 }
123
124 public void setVars(Map vars) {
125 this.vars.clear();
126 this.vars.putAll( vars );
127 }
128
129 public Map getVars() {
130 return this.vars;
131 }
132 }
133
134
135 class JellyMap implements Map {
136
137 private JellyContext context;
138
139 JellyMap(JellyContext context) {
140 this.context = context;
141 }
142
143 public Object get(Object key) {
144 return context.findVariable( (String) key );
145 }
146
147 public void clear() {
148 // not implemented
149 }
150
151 public boolean containsKey(Object key) {
152 return ( get( key ) != null );
153 }
154
155 public boolean containsValue(Object value) {
156 return false;
157 }
158
159 public Set entrySet() {
160 return null;
161 }
162
163 public boolean isEmpty() {
164 return false;
165 }
166
167 public Set keySet() {
168 return null;
169 }
170
171 public Object put(Object key, Object value) {
172 return null;
173 }
174
175 public void putAll(Map t) {
176 // not implemented
177 }
178
179 public Object remove(Object key) {
180 return null;
181 }
182
183 public int size() {
184 return -1;
185 }
186
187 public Collection values() {
188 return null;
189 }
190 }
This page was automatically generated by Maven