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1
17
18 package org.apache.avalon.fortress.impl.lookup;
19
20 import org.apache.avalon.fortress.Container;
21 import org.apache.avalon.fortress.impl.handler.ComponentHandler;
22 import org.apache.avalon.framework.service.ServiceException;
23 import org.apache.avalon.framework.service.ServiceSelector;
24
25 import java.util.Collections  ;
26 import java.util.HashMap ;
27 import java.util.Map ;
28
29
37 public class FortressServiceSelector
38 implements ServiceSelector
39 {
40 private final String m_key;
41 private final Container m_container;
42 private final Map m_used;
43
44
49 public FortressServiceSelector( final Container container,
50 final String key )
51 {
52 if ( null == container )
53 {
54 throw new NullPointerException ( "impl" );
55 }
56 if ( null == key )
57 {
58 throw new NullPointerException ( "key" );
59 }
60
61 m_key = key;
62 m_container = container;
63 m_used = Collections.synchronizedMap(new HashMap ());
64 }
65
66 public Object select( final Object hint )
67 throws ServiceException
68 {
69 try
70 {
71 final ComponentHandler handler = getHandler( hint );
72 final Object component = handler.get();
73 m_used.put( new ComponentKey( component ), handler );
74 return component;
75 }
76 catch ( final ServiceException ce )
77 {
78 throw ce; }
80 catch ( final Exception e )
81 {
82 final String name = m_key + "/" + hint.toString();
83 final String message = "Could not return a reference to the Component";
84 throw new ServiceException( name, message, e );
85 }
86 }
87
88 public boolean isSelectable( final Object hint )
89 {
90 return m_container.has( m_key, hint );
91 }
92
93 public void release( final Object component )
94 {
95 final ComponentHandler handler =
96 (ComponentHandler) m_used.remove( new ComponentKey( component ) );
97 if ( null != handler )
98 {
99 handler.put( component );
100 }
101 }
102
103 private ComponentHandler getHandler( final Object hint )
104 throws ServiceException
105 {
106 if ( null == hint )
107 {
108 final String message = "hint cannot be null";
109 throw new IllegalArgumentException ( message );
110 }
111
112 final ComponentHandler handler =
113 (ComponentHandler) m_container.get( m_key, hint );
114 if ( null == handler )
115 {
116 final String message =
117 "The hint does not exist in the ComponentSelector";
118 throw new ServiceException( m_key + "/" + hint.toString(),
119 message );
120 }
121 return handler;
122 }
123
124 public String getKey()
125 {
126 return m_key;
127 }
128 }
129 |
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