blob: 700f16ee5190f65fea4fcd7bf212fa85f7edf79f (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
|
// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.collections;
import com.yahoo.concurrent.CopyOnWriteHashMap;
import java.lang.reflect.Method;
import java.util.function.Consumer;
/**
* This will cache methods solved by reflection as reflection is expensive.
* Note that if the bundle from which the method is removed/changed you might have
* a problem... A ClassCastException might be one indication. Then clearing the cache and retrying it
* once to see if it goes away might be a solution.
* @author baldersheim
*/
public final class MethodCache {
private final String methodName;
private final CopyOnWriteHashMap<String, Pair<Class<?>, Method>> cache = new CopyOnWriteHashMap<>();
public MethodCache(String methodName) {
this.methodName = methodName;
}
/*
Clear all cached methods. Might be a wise thing to do, if you have cached some methods
that have changed due to new bundles being reloaded.
*/
public void clear() {
cache.clear();
}
public Method get(Object object) {
return get(object, null);
}
public Method get(Object object, Consumer<String> onPut) {
Pair<Class<?>, Method> pair = cache.get(object.getClass().getName());
// When changing bundles, you might end up having cached the old method pointing to the old bundle.
// That will then lead to a class cast exception when invoking the wrong clone method.
// Whenever we detect a new class with the same name, we therefore drop the entire cache.
// This is also the reason for caching the pair of method and original class—not just the method.
if (pair != null && pair.getFirst() != object.getClass()) {
cache.clear();
pair = null;
}
Method method = pair == null ? null : pair.getSecond();
if (pair == null) {
method = lookupMethod(object);
cache.put(object.getClass().getName(), new Pair<>(object.getClass(), method));
if (onPut != null)
onPut.accept(object.getClass().getName());
}
return method;
}
private Method lookupMethod(Object object) {
try {
return object.getClass().getMethod(methodName);
} catch (NoSuchMethodException e) {
return null;
}
}
}
|
