org.springsource.loaded.ri.JavaMethodCache Maven / Gradle / Ivy
/*
* Copyright 2010-2012 VMware and contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springsource.loaded.ri;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import org.objectweb.asm.Type;
import org.springsource.loaded.MethodMember;
/**
* Creating Java Method objects for a given MethodMember is rather expensive because it typically involves getting. The declared
* methods of a Class and searching for one that matches the method signature. This is most problematic when we are trying to get a
* Method for an array of MethodMembers, because in this case we will end up repeating the process multiple times. A JavaMethodCache
* instance can cache Method objects from the first time we iterate the declared methods of a class so subsequently we can just get
* the other methods from the cache.
*
* @author Kris De Volder
* @since 0.5.0
*/
public class JavaMethodCache {
//TODO: [...] This cache uses string+descriptor for key. It may be possible to cache method objects inside MethodMembers
// themselves, which would make for much quicker 'lookup'.
/*
* This class is used to initialise the cache in a thread safe manner. I.e. a fully filled map should be passed into the cache's
* initialize method, so that the 'isInitialized' method will not return true unless initialisation is complete and all entries
* are present.
*/
public static class Initializer {
//To build up initial map entries with 'put'
private Map cache = new HashMap();
protected void put(Method method) {
cache.put(method.getName() + Type.getMethodDescriptor(method), method);
}
}
/*
* Map indexed by name+descriptor.
*/
private Map cache = null;
public boolean isInitialized() {
return cache != null;
}
/*
* This method should be called to put all entries into the map.
*/
public void initialize(Initializer init) {
this.cache = init.cache;
init.cache = null; // Not strictly necessary, but prevents reuse of the initializer.
}
public Method get(MethodMember methodMember) {
return cache.get(methodMember.getNameAndDescriptor());
}
}