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1   /*
2    * Copyright (C) 2004 TiongHiang Lee
3    *
4    * This library is free software; you can redistribute it and/or
5    * modify it under the terms of the GNU Lesser General Public
6    * License as published by the Free Software Foundation; either
7    * version 2.1 of the License, or (at your option) any later version.
8    *
9    * This library is distributed in the hope that it will be useful,
10   * but WITHOUT ANY WARRANTY; without even the implied warranty of
11   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12   * Lesser General Public License for more details.
13   *
14   * You should have received a copy of the GNU Lesser General Public
15   * License along with this library; if not,  write to the Free Software
16   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
17   *
18   * Email: thlee@onemindsoft.org
19   */
20  
21  package org.onemind.commons.invoke;
22  
23  import java.util.*;
24  import java.util.HashMap;
25  import java.util.Map;
26  import org.onemind.commons.java.lang.reflect.ReflectUtils;
27  /***
28   * An invocable that contain a list of invocable functions to be invoke upon. In current implementation, it can only contains on
29   * function with the specific name (regardless of arg types)
30   * TODO: improve to allow multiple functions with same name	(different args)
31   * @todo improve to allow multiple functions with same name (different args)
32   * @author TiongHiang Lee (thlee@onemindsoft.org)
33   * @version $Id: AbstractInvocable.java,v 1.1 2005/01/24 05:51:36 thlee Exp $ $Name:  $
34   * @todo extend to allow multiple method with same name but different arg types
35   * TODO extend to allow multiple method with same name but different arg types
36   */
37  public abstract class AbstractInvocable implements Invocable
38  {
39  
40      /*** the functions **/
41      private Map _functions = new HashMap();
42  
43      /***
44       * Add an function
45       * @param functionName the function name
46       * @param function the function
47       */
48      public void addFunction(InvocableFunction function)
49      {
50          Object key = ReflectUtils.toMethodString(function.getName(), function.getArgTypes());
51          _functions.put(key, function);
52      }
53  
54      /*** 
55       * {@inheritDoc}
56       */
57      public InvocableFunction getFunction(String functionName, Object[] args)
58      {
59          return getFunction(functionName, ReflectUtils.toArgTypes(args));
60      }
61  
62      /*** 
63       * {@inheritDoc}
64       */
65      public InvocableFunction getFunction(String functionName, Class[] argTypes)
66      {
67          Object key = ReflectUtils.toMethodString(functionName, argTypes);
68          InvocableFunction func = (InvocableFunction) _functions.get(key);
69          if (func != null)
70          {
71              return func;
72          } else
73          {
74              //search for it
75              Iterator it = _functions.values().iterator();
76              while (it.hasNext())
77              {
78                  func = (InvocableFunction) it.next();
79                  if (functionName.equals(func.getName()) && func.canInvokeOn(argTypes))
80                  {
81                      return func;
82                  }
83              }
84              return null;
85          }
86      }
87  
88      /***
89       * {@inheritDoc}
90       */
91      public boolean canInvoke(String functionName, Object[] args)
92      {
93          InvocableFunction f = getFunction(functionName, args);
94          return (f != null);
95      }
96  
97      /***
98       * {@inheritDoc}
99       */
100     public Object invoke(String functionName, Object[] args) throws Exception
101     {
102         InvocableFunction function = getFunction(functionName, args);
103         if (function != null)
104         {
105             return function.invoke(this, args);
106         } else
107         {
108             throw new NoSuchMethodException("Method " + ReflectUtils.toMethodString(functionName, args) + " not found for " + this);
109         }
110     }
111 
112     /***
113      * Get all the functions
114      * @return the functions
115      */
116     public Collection getFunctions()
117     {
118         return Collections.unmodifiableCollection(_functions.values());
119     }
120 }