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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.util.Coercion;
20  import org.apache.commons.jexl.JexlContext;
21  
22  /***
23   *  Subtraction
24   *
25   *  @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
26   *  @author <a href="mailto:mhw@kremvax.net">Mark H. Wilkinson</a>
27   *  @version $Id: ASTSubtractNode.java,v 1.5 2004/02/28 13:45:20 yoavs Exp $
28   */
29  public class ASTSubtractNode extends SimpleNode
30  {
31      public ASTSubtractNode(int id)
32      {
33          super(id);
34      }
35  
36      public ASTSubtractNode(Parser p, int id)
37      {
38          super(p, id);
39      }
40  
41      public Object value(JexlContext context)
42          throws Exception
43      {
44          Object left = ((SimpleNode) jjtGetChild(0)).value(context);
45          Object right = ((SimpleNode) jjtGetChild(1)).value(context);
46  
47          /*
48           *  the spec says 'and', I think 'or'
49           */
50          if (left == null && right == null)
51              return new Integer(0);
52  
53          /*
54           *  if anything is float, double or string with ( "." | "E" | "e")
55           *  coerce all to doubles and do it
56           */
57          if ( left instanceof Float || left instanceof Double
58              || right instanceof Float || right instanceof Double
59              || (  left instanceof String
60                   && (  ((String) left).indexOf(".") != -1 ||
61                      ((String) left).indexOf("e") != -1 ||
62                      ((String) left).indexOf("E") != -1 )
63              )
64              || (  right instanceof String
65                  && (  ((String) right).indexOf(".") != -1 ||
66                  ((String) right).indexOf("e") != -1 ||
67                  ((String) right).indexOf("E") != -1 )
68                 )
69          )
70          {
71              Double l = Coercion.coerceDouble(left);
72              Double r = Coercion.coerceDouble(right);
73  
74              return new Double(l.doubleValue() - r.doubleValue());
75          }
76  
77          /*
78           * otherwise to longs with thee!
79           */
80  
81          Long l = Coercion.coerceLong(left);
82          Long r = Coercion.coerceLong(right);
83  
84          /*
85           *  TODO - this is actually wrong - JSTL says to return a Long
86           *  but we have problems where you have something like 
87           * 
88           *     foo.bar( a - b )
89           * 
90           *  where bar wants an int... 
91           * 
92           */
93          long v = l.longValue() - r.longValue();
94  
95          if ( left instanceof Integer && right instanceof Integer )
96          {
97              return new Integer((int) v);
98          }
99          else
100         {
101             return new Long(v);
102         }
103      }
104     /*** Accept the visitor. **/
105     public Object jjtAccept(ParserVisitor visitor, Object data)
106     {
107         return visitor.visit(this, data);
108     }
109 }