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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 java.lang.reflect.InvocationTargetException;
23  
24  import org.apache.velocity.runtime.log.Log;
25  import org.apache.velocity.util.introspection.Introspector;
26  
27  
28  /**
29   * Executor that simply tries to execute a put(key, value)
30   * operation. This will try to find a put(key) method
31   * for any type of object, not just objects that
32   * implement the Map interface as was previously
33   * the case.
34   *
35   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
36   * @author <a href="mailto:henning@apache.org">Henning P. Schmiedehausen</a>
37   * @version $Id: PutExecutor.java 463298 2006-10-12 16:10:32Z henning $
38   */
39  public class PutExecutor extends SetExecutor
40  {
41      private final Introspector introspector;
42      private final String property;
43  
44      /**
45       * @param log
46       * @param introspector
47       * @param clazz
48       * @param arg
49       * @param property
50       */
51      public PutExecutor(final Log log, final Introspector introspector,
52              final Class clazz, final Object arg, final String property)
53      {
54          this.log = log;
55          this.introspector = introspector;
56          this.property = property;
57  
58          discover(clazz, arg);
59      }
60  
61      /**
62       * @param clazz
63       * @param arg
64       */
65      protected void discover(final Class clazz, final Object arg)
66      {
67          Object [] params;
68  
69          // If you passed in null as property, we don't use the value
70          // for parameter lookup. Instead we just look for put(Object) without
71          // any parameters.
72          //
73          // In any other case, the following condition will set up an array
74          // for looking up put(String, Object) on the class.
75  
76          if (property == null)
77          {
78              // The passed in arg object is used by the Cache to look up the method.
79              params = new Object[] { arg };
80          }
81          else
82          {
83              params = new Object[] { property, arg };
84          }
85  
86          try
87          {
88              setMethod(introspector.getMethod(clazz, "put", params));
89          }
90          /**
91           * pass through application level runtime exceptions
92           */
93          catch( RuntimeException e )
94          {
95              throw e;
96          }
97          catch(Exception e)
98          {
99              log.error("While looking for put('" + params[0] + "') method:", e);
100         }
101     }
102 
103     /**
104      * @see org.apache.velocity.runtime.parser.node.SetExecutor#execute(java.lang.Object, java.lang.Object)
105      */
106     public Object execute(final Object o, final Object value)
107         throws IllegalAccessException,  InvocationTargetException
108     {
109         Object [] params;
110 
111         if (isAlive())
112         {
113             // If property != null, pass in the name for put(key, value). Else just put(value).
114             if (property == null)
115             {
116                 params = new Object [] { value };
117             }
118             else
119             {
120                 params = new Object [] { property, value };
121             }
122 
123             return getMethod().invoke(o, params);
124         }
125 
126         return null;
127     }
128 }