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20 package org.apache.mina.filter.traffic;
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.common.IoBuffer;
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45 public class DefaultMessageSizeEstimator implements MessageSizeEstimator {
46
47 private final ConcurrentMap<Class<?>, Integer> class2size = new ConcurrentHashMap<Class<?>, Integer>();
48
49 public DefaultMessageSizeEstimator() {
50 class2size.put(boolean.class, 4);
51 class2size.put(byte.class, 1);
52 class2size.put(char.class, 2);
53 class2size.put(short.class, 2);
54 class2size.put(int.class, 4);
55 class2size.put(long.class, 8);
56 class2size.put(float.class, 4);
57 class2size.put(double.class, 8);
58 class2size.put(void.class, 0);
59 }
60
61 public int estimateSize(Object message) {
62 if (message == null) {
63 return 8;
64 }
65
66 int answer = 8 + estimateSize(message.getClass(), null);
67
68 if (message instanceof IoBuffer) {
69 answer += ((IoBuffer) message).remaining();
70 } else if (message instanceof CharSequence) {
71 answer += ((CharSequence) message).length() << 1;
72 } else if (message instanceof Iterable) {
73 for (Object m: (Iterable<?>) message) {
74 answer += estimateSize(m);
75 }
76 }
77
78 return align(answer);
79 }
80
81 private int estimateSize(Class<?> clazz, Set<Class<?>> visitedClasses) {
82 Integer objectSize = class2size.get(clazz);
83 if (objectSize != null) {
84 return objectSize;
85 }
86
87 if (visitedClasses != null) {
88 if (visitedClasses.contains(clazz)) {
89 return 0;
90 }
91 } else {
92 visitedClasses = new HashSet<Class<?>>();
93 }
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95 visitedClasses.add(clazz);
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97 int answer = 8;
98 for (Class<?> c = clazz; c != null; c = c.getSuperclass()) {
99 Field[] fields = c.getDeclaredFields();
100 for (Field f: fields) {
101 if ((f.getModifiers() & Modifier.STATIC) != 0) {
102
103 continue;
104 }
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106 answer += estimateSize(f.getType(), visitedClasses);
107 }
108 }
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110 visitedClasses.remove(clazz);
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113 answer = align(answer);
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116 class2size.putIfAbsent(clazz, answer);
117 return answer;
118 }
119
120 private static int align(int size) {
121 if (size % 8 != 0) {
122 size /= 8;
123 size ++;
124 size *= 8;
125 }
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127 return size;
128 }
129 }