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1   /*
2    * Copyright 2002-2006 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 398325 2006-04-30 12:34:29Z dion $
28   */
29  public class ASTSubtractNode extends SimpleNode {
30      /***
31       * Create the node given an id.
32       * 
33       * @param id node id.
34       */
35      public ASTSubtractNode(int id) {
36          super(id);
37      }
38  
39      /***
40       * Create a node with the given parser and id.
41       * 
42       * @param p a parser.
43       * @param id node id.
44       */
45      public ASTSubtractNode(Parser p, int id) {
46          super(p, id);
47      }
48  
49      /*** {@inheritDoc} */
50      public Object value(JexlContext context) throws Exception {
51          Object left = ((SimpleNode) jjtGetChild(0)).value(context);
52          Object right = ((SimpleNode) jjtGetChild(1)).value(context);
53  
54          /*
55           * the spec says 'and', I think 'or'
56           */
57          if (left == null && right == null) {
58              return new Byte((byte) 0);
59          }
60  
61          /*
62           * if anything is float, double or string with ( "." | "E" | "e") coerce
63           * all to doubles and do it
64           */
65          if (left instanceof Float
66              || left instanceof Double
67              || right instanceof Float
68              || right instanceof Double
69              || (left instanceof String 
70                  && (((String) left).indexOf(".") != -1 
71                      || ((String) left).indexOf("e") != -1 
72                      || ((String) left).indexOf("E") != -1))
73              || (right instanceof String 
74                  && (((String) right).indexOf(".") != -1 
75                      || ((String) right).indexOf("e") != -1 
76                      || ((String) right).indexOf("E") != -1))) {
77              Double l = Coercion.coerceDouble(left);
78              Double r = Coercion.coerceDouble(right);
79  
80              return new Double(l.doubleValue() - r.doubleValue());
81          }
82  
83          /*
84           * otherwise to longs with thee!
85           */
86  
87          Long l = Coercion.coerceLong(left);
88          Long r = Coercion.coerceLong(right);
89  
90          return new Long(l.longValue() - r.longValue());
91  
92      }
93  
94      /*** {@inheritDoc} */
95      public Object jjtAccept(ParserVisitor visitor, Object data) {
96          return visitor.visit(this, data);
97      }
98  }