1 /*
2 * $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/taglibs/bsf/src/java/org/apache/commons/jelly/tags/bsf/BSFExpression.java,v 1.1 2002/05/21 07:58:55 jstrachan Exp $
3 * $Revision: 1.1 $
4 * $Date: 2002/05/21 07:58:55 $
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: BSFExpression.java,v 1.1 2002/05/21 07:58:55 jstrachan Exp $
61 */
62 package org.apache.commons.jelly.tags.bsf;
63
64 import com.ibm.bsf.BSFEngine;
65 import com.ibm.bsf.BSFManager;
66
67 import java.util.Iterator;
68
69 import org.apache.commons.jelly.JellyContext;
70 import org.apache.commons.jelly.expression.ExpressionSupport;
71
72 import org.apache.commons.logging.Log;
73 import org.apache.commons.logging.LogFactory;
74
75
76 /*** Represents a BSF expression
77 *
78 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
79 * @version $Revision: 1.1 $
80 */
81 public class BSFExpression extends ExpressionSupport {
82
83 /*** The Log to which logging calls will be made. */
84 private static final Log log = LogFactory.getLog( BSFExpression.class );
85
86 /*** The expression */
87 private String text;
88
89 /*** The BSF Engine to evaluate expressions */
90 private BSFEngine engine;
91 /*** The BSF Manager to evaluate expressions */
92 private BSFManager manager;
93
94 /*** The adapter to BSF's ObjectRegistry that uses the JellyContext */
95 private JellyContextRegistry registry;
96
97 public BSFExpression(String text, BSFEngine engine, BSFManager manager, JellyContextRegistry registry) {
98 this.text = text;
99 this.engine = engine;
100 this.manager = manager;
101 this.registry = registry;
102 }
103
104 // Expression interface
105 //-------------------------------------------------------------------------
106 public Object evaluate(JellyContext context) {
107 // XXXX: unfortunately we must sychronize evaluations
108 // so that we can swizzle in the context.
109 // maybe we could create an expression from a context
110 // (and so create a BSFManager for a context)
111 synchronized (registry) {
112 registry.setJellyContext(context);
113
114 try {
115 // XXXX: hack - there must be a better way!!!
116 for ( Iterator iter = context.getVariableNames(); iter.hasNext(); ) {
117 String name = (String) iter.next();
118 Object value = context.getVariable( name );
119 manager.declareBean( name, value, value.getClass() );
120 }
121 return engine.eval( text, -1, -1, text );
122 }
123 catch (Exception e) {
124 log.warn( "Caught exception evaluating: " + text + ". Reason: " + e, e );
125 return null;
126 }
127 }
128 }
129 }
This page was automatically generated by Maven