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1
15 package org.apache.hivemind.service.impl;
16
17 import java.beans.BeanInfo  ;
18 import java.beans.EventSetDescriptor ;
19 import java.beans.IntrospectionException ;
20 import java.beans.Introspector ;
21 import java.lang.reflect.Method ;
22 import java.util.HashMap ;
23 import java.util.Map ;
24
25 import org.apache.hivemind.ErrorLog;
26 import org.apache.hivemind.HiveMind;
27 import org.apache.hivemind.Location;
28 import org.apache.hivemind.impl.BaseLocatable;
29 import org.apache.hivemind.service.EventLinker;
30
31
38 public class EventLinkerImpl extends BaseLocatable implements EventLinker
39 {
40 private ErrorLog _errorLog;
41
42
45 private Map _producerEventSets;
46
47 public EventLinkerImpl(ErrorLog errorLog)
48 {
49 _errorLog = errorLog;
50 }
51
52 public void addEventListener(Object producer, String eventSetName, Object consumer,
53 Location location)
54 {
55 EventSetDescriptor [] sets = getEventSets(producer);
56 boolean nameMatch = HiveMind.isNonBlank(eventSetName);
57 Class consumerClass = consumer.getClass();
58
59 int count = 0;
60 for (int i = 0; i < sets.length; i++)
61 {
62 EventSetDescriptor set = sets[i];
63 String name = set.getName();
64
65 if (nameMatch)
66 {
67 if (!eventSetName.equals(name))
68 continue;
69
70 if (isAssignable(set, consumerClass))
71 addEventListener(producer, set, consumer, location);
72 else
73 {
74 _errorLog.error(
75 ServiceMessages.notCompatibleWithEvent(consumer, set, producer),
76 location,
77 null);
78 }
79
80 return;
81 }
82
83
85 if (isAssignable(set, consumerClass))
86 {
87 addEventListener(producer, set, consumer, location);
88 count++;
89 }
90 }
91
92 if (count == 0)
93 {
94 if (nameMatch)
95 _errorLog.error(
96 ServiceMessages.noSuchEventSet(producer, eventSetName),
97 location,
98 null);
99 else
100 _errorLog.error(ServiceMessages.noEventMatches(consumer, producer), location, null);
101 }
102 }
103
104 private boolean isAssignable(EventSetDescriptor set, Class consumerClass)
105 {
106 return set.getListenerType().isAssignableFrom(consumerClass);
107 }
108
109 private void addEventListener(Object producer, EventSetDescriptor set, Object consumer,
110 Location location)
111 {
112 Method m = set.getAddListenerMethod();
113
114 try
115 {
116 m.invoke(producer, new Object []
117 { consumer });
118 }
119 catch (Exception ex)
120 {
121 _errorLog.error(ServiceMessages.unableToAddListener(
122 producer,
123 set,
124 consumer,
125 location,
126 ex), location, ex);
127
128 }
129 }
130
131 private EventSetDescriptor [] getEventSets(Object producer)
132 {
133 return getEventSets(producer.getClass());
134 }
135
136 private synchronized EventSetDescriptor [] getEventSets(Class producerClass)
137 {
138 EventSetDescriptor [] result = null;
139
140 if (_producerEventSets == null)
141 _producerEventSets = new HashMap ();
142 else
143 result = (EventSetDescriptor []) _producerEventSets.get(producerClass);
144
145 if (result == null)
146 {
147 result = findEventSets(producerClass);
148
149 _producerEventSets.put(producerClass, result);
150 }
151
152 return result;
153 }
154
155 private EventSetDescriptor [] findEventSets(Class producerClass)
156 {
157 synchronized (HiveMind.INTROSPECTOR_MUTEX)
158 {
159 try
160 {
161 BeanInfo beanInfo = Introspector.getBeanInfo(producerClass);
162
163
166 return beanInfo.getEventSetDescriptors();
167 }
168 catch (IntrospectionException ex)
169 {
170 _errorLog.error(
171 ServiceMessages.unableToIntrospectClass(producerClass, ex),
172 null,
173 ex);
174
175 return new EventSetDescriptor [0];
176 }
177 }
178 }
179
180 } |
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