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Java > Open Source Codes > org > apache > velocity > runtime > parser > node > ASTLTNode


1 package org.apache.velocity.runtime.parser.node;
2
3 /*
4  * Copyright 2000-2001,2004 The Apache Software Foundation.
5  *
6  * Licensed under the Apache License, Version 2.0 (the "License");
7  * you may not use this file except in compliance with the License.
8  * You may obtain a copy of the License at
9  *
10  * http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18
19 import org.apache.velocity.context.InternalContextAdapter;
20 import org.apache.velocity.runtime.parser.Parser;
21
22 import org.apache.velocity.exception.MethodInvocationException;
23
24 public class ASTLTNode extends SimpleNode
25 {
26     public ASTLTNode(int id)
27     {
28         super(id);
29     }
30
31     public ASTLTNode(Parser p, int id)
32     {
33         super(p, id);
34     }
35
36     /** Accept the visitor. **/
37     public Object JavaDoc jjtAccept(ParserVisitor visitor, Object JavaDoc data)
38     {
39         return visitor.visit(this, data);
40     }
41
42     public boolean evaluate(InternalContextAdapter context)
43         throws MethodInvocationException
44     {
45         /*
46          * get the two args
47          */
48         
49         Object JavaDoc left = jjtGetChild(0).value( context );
50         Object JavaDoc right = jjtGetChild(1).value( context );
51
52         /*
53          * if either is null, lets log and bail
54          */
55
56         if (left == null || right == null)
57         {
58             rsvc.error( ( left == null ? "Left" : "Right" )
59                            + " side ("
60                            + jjtGetChild( (left == null? 0 : 1) ).literal()
61                            + ") of '<' operation has null value."
62                            + " Operation not possible. "
63                            + context.getCurrentTemplateName() + " [line "
64                            + getLine()
65                            + ", column " + getColumn() + "]");
66             return false;
67         }
68         
69         /*
70          * if not an Integer, not much we can do either
71          */
72
73         if ( !( left instanceof Integer JavaDoc ) || !( right instanceof Integer JavaDoc ))
74         {
75             rsvc.error( ( !( left instanceof Integer JavaDoc ) ? "Left" : "Right" )
76                            + " side of '<' operation is not a valid type. "
77                            + " It is a " + ( !( left instanceof Integer JavaDoc ) ? left.getClass() : right.getClass() )
78                            + ". Currently only integers (1,2,3...) and Integer type is supported. "
79                            + context.getCurrentTemplateName() + " [line " + getLine()
80                            + ", column " + getColumn() + "]");
81  
82             return false;
83         }
84
85         return ((Integer JavaDoc) left).intValue() < ((Integer JavaDoc) right).intValue();
86     }
87
88     public Object JavaDoc value(InternalContextAdapter context)
89         throws MethodInvocationException
90     {
91         boolean val = evaluate(context);
92
93         return val ? Boolean.TRUE : Boolean.FALSE;
94     }
95
96 }
97
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