1 package org.apache.velocity.runtime.parser.node;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import org.apache.velocity.context.InternalContextAdapter;
23 import org.apache.velocity.exception.MethodInvocationException;
24 import org.apache.velocity.runtime.parser.Parser;
25
26 /**
27 * Please look at the Parser.jjt file which is
28 * what controls the generation of this class.
29 *
30 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
31 * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
32 * @version $Id: ASTAndNode.java 687184 2008-08-19 22:16:39Z nbubna $
33 */
34 public class ASTAndNode extends SimpleNode
35 {
36 /**
37 * @param id
38 */
39 public ASTAndNode(int id)
40 {
41 super(id);
42 }
43
44 /**
45 * @param p
46 * @param id
47 */
48 public ASTAndNode(Parser p, int id)
49 {
50 super(p, id);
51 }
52
53 /**
54 * @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.node.ParserVisitor, java.lang.Object)
55 */
56 public Object jjtAccept(ParserVisitor visitor, Object data)
57 {
58 return visitor.visit(this, data);
59 }
60
61 /**
62 * Returns the value of the expression.
63 * Since the value of the expression is simply the boolean
64 * result of evaluate(), lets return that.
65 * @param context
66 * @return The value of the expression.
67 * @throws MethodInvocationException
68 */
69 public Object value(InternalContextAdapter context)
70 throws MethodInvocationException
71 {
72 // TODO: JDK 1.4+ -> valueOf()
73 // return new Boolean(evaluate(context));
74 return evaluate(context) ? Boolean.TRUE : Boolean.FALSE;
75 }
76
77 /**
78 * logical and :
79 * null && right = false
80 * left && null = false
81 * null && null = false
82 * @param context
83 * @return True if both sides are true.
84 * @throws MethodInvocationException
85 */
86 public boolean evaluate( InternalContextAdapter context)
87 throws MethodInvocationException
88 {
89 Node left = jjtGetChild(0);
90 Node right = jjtGetChild(1);
91
92 /*
93 * null == false
94 */
95 if (left == null || right == null)
96 {
97 return false;
98 }
99
100 /*
101 * short circuit the test. Don't eval the RHS if the LHS is false
102 */
103
104 if( left.evaluate( context ) )
105 {
106 if ( right.evaluate( context ) )
107 {
108 return true;
109 }
110 }
111
112 return false;
113 }
114 }
115