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20 package org.apache.mina.filter.executor;
21
22 import java.lang.reflect.Field;
23 import java.lang.reflect.Modifier;
24 import java.util.HashSet;
25 import java.util.Set;
26 import java.util.concurrent.ConcurrentHashMap;
27 import java.util.concurrent.ConcurrentMap;
28
29 import org.apache.mina.core.buffer.IoBuffer;
30 import org.apache.mina.core.session.IoEvent;
31 import org.apache.mina.core.write.WriteRequest;
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46 public class DefaultIoEventSizeEstimator implements IoEventSizeEstimator {
47
48 private final ConcurrentMap<Class<?>, Integer> class2size = new ConcurrentHashMap<Class<?>, Integer>();
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53
54 public DefaultIoEventSizeEstimator() {
55 class2size.put(boolean.class, 4);
56 class2size.put(byte.class, 1);
57 class2size.put(char.class, 2);
58 class2size.put(int.class, 4);
59 class2size.put(short.class, 2);
60 class2size.put(long.class, 8);
61 class2size.put(float.class, 4);
62 class2size.put(double.class, 8);
63 class2size.put(void.class, 0);
64 }
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66
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68
69 public int estimateSize(IoEvent event) {
70 return estimateSize((Object) event) + estimateSize(event.getParameter());
71 }
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77
78 public int estimateSize(Object message) {
79 if (message == null) {
80 return 8;
81 }
82
83 int answer = 8 + estimateSize(message.getClass(), null);
84
85 if (message instanceof IoBuffer) {
86 answer += ((IoBuffer) message).remaining();
87 } else if (message instanceof WriteRequest) {
88 answer += estimateSize(((WriteRequest) message).getMessage());
89 } else if (message instanceof CharSequence) {
90 answer += ((CharSequence) message).length() << 1;
91 } else if (message instanceof Iterable) {
92 for (Object m: (Iterable<?>) message) {
93 answer += estimateSize(m);
94 }
95 }
96
97 return align(answer);
98 }
99
100 private int estimateSize(Class<?> clazz, Set<Class<?>> visitedClasses) {
101 Integer objectSize = class2size.get(clazz);
102 if (objectSize != null) {
103 return objectSize;
104 }
105
106 if (visitedClasses != null) {
107 if (visitedClasses.contains(clazz)) {
108 return 0;
109 }
110 } else {
111 visitedClasses = new HashSet<Class<?>>();
112 }
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114 visitedClasses.add(clazz);
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116 int answer = 8;
117 for (Class<?> c = clazz; c != null; c = c.getSuperclass()) {
118 Field[] fields = c.getDeclaredFields();
119 for (Field f: fields) {
120 if ((f.getModifiers() & Modifier.STATIC) != 0) {
121
122 continue;
123 }
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125 answer += estimateSize(f.getType(), visitedClasses);
126 }
127 }
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129 visitedClasses.remove(clazz);
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132 answer = align(answer);
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135 class2size.putIfAbsent(clazz, answer);
136 return answer;
137 }
138
139 private static int align(int size) {
140 if (size % 8 != 0) {
141 size /= 8;
142 size ++;
143 size *= 8;
144 }
145 return size;
146 }
147 }