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1   /*
2    * Copyright 2002,2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package org.apache.commons.jexl.parser;
18  
19  import org.apache.commons.jexl.JexlContext;
20  import org.apache.commons.jexl.util.Coercion;
21  
22  /***
23   *  LT : a < b
24   *
25   *  Follows A.3.6.1 of the JSTL 1.0 specification
26   *
27   *  @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
28   *  @author <a href="mailto:proyal@apache.org">Peter Royal</a>
29   *  @version $Id: ASTLTNode.java,v 1.5 2004/02/28 13:45:20 yoavs Exp $
30   */
31  public class ASTLTNode extends SimpleNode
32  {
33      public ASTLTNode(int id)
34      {
35          super(id);
36      }
37  
38      public ASTLTNode(Parser p, int id)
39      {
40          super(p, id);
41      }
42  
43      /*** Accept the visitor. **/
44      public Object jjtAccept(ParserVisitor visitor, Object data)
45      {
46          return visitor.visit(this, data);
47      }
48  
49      public Object value(JexlContext jc)
50          throws Exception
51      {
52          /*
53           * now get the values
54           */
55  
56          Object left = ( (SimpleNode) jjtGetChild(0)).value(jc);
57          Object right = ( (SimpleNode) jjtGetChild(1)).value(jc);
58  
59          if( ( left == right ) || ( left == null ) || ( right == null ) )
60          {
61              return Boolean.FALSE;
62          }
63          else if( Coercion.isFloatingPoint( left ) || Coercion.isFloatingPoint( right ) )
64          {
65              double leftDouble = Coercion.coerceDouble( left ).doubleValue();
66              double rightDouble = Coercion.coerceDouble( right ).doubleValue();
67  
68              return leftDouble < rightDouble
69                  ? Boolean.TRUE
70                  : Boolean.FALSE;
71          }
72          else if( Coercion.isNumberable( left ) || Coercion.isNumberable( right ) )
73          {
74              long leftLong = Coercion.coerceLong( left ).longValue();
75              long rightLong = Coercion.coerceLong( right ).longValue();
76  
77              return leftLong < rightLong
78                  ? Boolean.TRUE
79                  : Boolean.FALSE;
80          }
81          else if( left instanceof String || right instanceof String )
82          {
83              String leftString = left.toString();
84              String rightString = right.toString();
85  
86              return leftString.compareTo( rightString ) < 0
87                  ? Boolean.TRUE
88                  : Boolean.FALSE;
89          }
90          else if( left instanceof Comparable )
91          {
92              return ( (Comparable)left ).compareTo( right ) < 0
93                  ? Boolean.TRUE
94                  : Boolean.FALSE;
95          }
96          else if( right instanceof Comparable )
97          {
98              return ( (Comparable)right ).compareTo( left ) > 0
99                  ? Boolean.TRUE
100                 : Boolean.FALSE;
101         }
102 
103         throw new Exception("Invalid comparison : LT ");
104     }
105 }