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.runtime.parser.Parser;
24 import org.apache.velocity.runtime.parser.ParserVisitor;
25 import org.apache.velocity.exception.MethodInvocationException;
26
27 /**
28 * Please look at the Parser.jjt file which is
29 * what controls the generation of this class.
30 *
31 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
32 * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
33 * @version $Id: ASTAndNode.java 463298 2006-10-12 16:10:32Z henning $
34 */
35 public class ASTAndNode extends SimpleNode
36 {
37 /**
38 * @param id
39 */
40 public ASTAndNode(int id)
41 {
42 super(id);
43 }
44
45 /**
46 * @param p
47 * @param id
48 */
49 public ASTAndNode(Parser p, int id)
50 {
51 super(p, id);
52 }
53
54 /**
55 * @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.ParserVisitor, java.lang.Object)
56 */
57 public Object jjtAccept(ParserVisitor visitor, Object data)
58 {
59 return visitor.visit(this, data);
60 }
61
62 /**
63 * Returns the value of the expression.
64 * Since the value of the expression is simply the boolean
65 * result of evaluate(), lets return that.
66 * @param context
67 * @return The value of the expression.
68 * @throws MethodInvocationException
69 */
70 public Object value(InternalContextAdapter context)
71 throws MethodInvocationException
72 {
73 // TODO: JDK 1.4+ -> valueOf()
74 return new Boolean(evaluate(context));
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 * if either is null, lets log and bail
94 */
95
96 if (left == null || right == null)
97 {
98 log.error((left == null ? "Left" : "Right") + " side of '&&' operation is null."
99 + " Operation not possible. "
100 + context.getCurrentTemplateName() + " [line " + getLine()
101 + ", column " + getColumn() + "]");
102 return false;
103 }
104
105 /*
106 * short circuit the test. Don't eval the RHS if the LHS is false
107 */
108
109 if( left.evaluate( context ) )
110 {
111 if ( right.evaluate( context ) )
112 {
113 return true;
114 }
115 }
116
117 return false;
118 }
119 }
120