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1
4 package com.tc.object.tx;
5
6 import EDU.oswego.cs.dl.util.concurrent.CopyOnWriteArrayList;
7
8 import com.tc.util.Assert;
9
10 import java.lang.reflect.Method  ;
11 import java.util.Collection ;
12 import java.util.IdentityHashMap ;
13 import java.util.Iterator ;
14 import java.util.Map ;
15
16
22 public class ChangeListenerCollection implements Collection {
23 private final Collection listeners = new CopyOnWriteArrayList();
24 private final String callbackMethod;
25 private final Map methodRefs = new IdentityHashMap ();
26 private final Class [] callbackSignature;
27
28 public static class NoSuchCallbackException extends RuntimeException {
29 public NoSuchCallbackException(String msg) {
30 super(msg);
31 }
32 }
33
34 public ChangeListenerCollection(String callbackMethod) {
35 super();
36 Assert.assertNotNull("callbackmethod", callbackMethod);
37 this.callbackMethod = callbackMethod;
38 this.callbackSignature = new Class [] { Iterator .class };
39 }
40
41 public synchronized boolean add(Object obj) {
42 if (obj == null) { throw new NullPointerException ("null not permitted in change listener collection"); }
43 findCallback(obj);
44 return listeners.add(obj);
45 }
46
47 private Method findCallback(Object o) {
48
53 Assert.assertNotNull(o);
54
55 if (!methodRefs.containsKey(o)) {
56 try {
57 Method method = o.getClass().getDeclaredMethod(callbackMethod, callbackSignature);
58 method.setAccessible(true);
59 methodRefs.put(o, method);
60 } catch (Exception e) {
61 throw new NoSuchCallbackException(e.getClass().getName() + " occured trying to locate callback method named "
63 + callbackMethod + " on class " + o.getClass());
64 }
65 }
66
67 return (Method ) methodRefs.get(o);
68 }
69
70 public boolean addAll(Collection c) {
71 throw new UnsupportedOperationException ();
72 }
73
74 public synchronized void clear() {
75 listeners.clear();
76 methodRefs.clear();
77 }
78
79 public boolean contains(Object o) {
80 return listeners.contains(o);
81 }
82
83 public boolean containsAll(Collection c) {
84 throw new UnsupportedOperationException ();
85 }
86
87 public boolean equals(Object obj) {
88 return this == obj;
89 }
90
91 public int hashCode() {
92 return listeners.hashCode();
93 }
94
95 public boolean isEmpty() {
96 return listeners.isEmpty();
97 }
98
99 public Iterator iterator() {
100 final Iterator internalIter = listeners.iterator();
101
102 return new Iterator () {
103 public void remove() {
104 throw new UnsupportedOperationException ();
106 }
107
108 public boolean hasNext() {
109 return internalIter.hasNext();
110 }
111
112 public Object next() {
113 return internalIter.next();
114 }
115 };
116 }
117
118 public synchronized boolean remove(Object o) {
119 if (null == o) { return false; }
120 methodRefs.remove(o);
121 return listeners.remove(o);
122 }
123
124 public boolean removeAll(Collection c) {
125 throw new UnsupportedOperationException ();
126 }
127
128 public boolean retainAll(Collection c) {
129 throw new UnsupportedOperationException ();
130 }
131
132 public int size() {
133 return listeners.size();
134 }
135
136 public Object [] toArray() {
137 return listeners.toArray();
138 }
139
140 public Object [] toArray(Object [] a) {
141 return listeners.toArray(a);
142 }
143
144 public String toString() {
145 StringBuffer buf = new StringBuffer ('[');
146
147 final Iterator iter = listeners.iterator();
148 boolean hasNext = iter.hasNext();
149 while (hasNext) {
150 Object obj = iter.next();
151 buf.append(obj == this ? "(this collection)" : String.valueOf(obj));
152 hasNext = iter.hasNext();
153 if (hasNext) buf.append(", ");
154 }
155
156 return buf.append(']').toString();
157 }
158
159 synchronized Method getCallbackFor(Object obj) {
160 Assert.assertNotNull(obj);
161 return (Method ) methodRefs.get(obj);
162 }
163 } |
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