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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.runtime.parser.Parser;
23  import org.apache.velocity.util.DuckType;
24  
25  /**
26   *  Handles <code>arg1 == arg2</code>
27   *
28   *  This operator requires that the LHS and RHS are both of the
29   *  same Class, both numbers or both coerce-able to strings.
30   *
31   *  @author <a href="mailto:wglass@forio.com">Will Glass-Husain</a>
32   *  @author <a href="mailto:pero@antaramusic.de">Peter Romianowski</a>
33   *  @author Nathan Bubna
34   */
35  public class ASTEQNode extends ASTComparisonNode
36  {
37      public ASTEQNode(int id)
38      {
39          super(id);
40      }
41  
42      public ASTEQNode(Parser p, int id)
43      {
44          super(p, id);
45      }
46  
47      @Override
48      public boolean compareNull(Object left, Object right)
49      {
50          // at least one is null, see if other is null or acts as a null
51          return left == right || DuckType.asNull(left == null ? right : left);
52      }
53  
54      public boolean numberTest(int compareResult)
55      {
56          return compareResult == 0;
57      }
58  
59      @Override
60      public boolean compareNonNumber(Object left, Object right)
61      {
62          /**
63           * if both are not null, then assume that if one class
64           * is a subclass of the other that we should use the equals operator
65           */
66          if (left.getClass().isAssignableFrom(right.getClass()) ||
67              right.getClass().isAssignableFrom(left.getClass()))
68          {
69              return left.equals(right);
70          }
71  
72          // coerce to string, remember getAsString() methods may return null
73          left = DuckType.asString(left);
74          right = DuckType.asString(right);
75          if (left == right)
76          {
77              return true;
78          }
79          else if (left == null || right == null)
80          {
81              return false;
82          }
83          else
84          {
85              return left.equals(right);
86          }
87      }
88  
89  }