/*
* Copyright 2013 the original author or authors.
*
* 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.gradle.internal.classloader;
import com.google.common.collect.MapMaker;
import java.io.Closeable;
import java.io.IOException;
import java.util.concurrent.ConcurrentMap;
public class CachingClassLoader extends ClassLoader implements ClassLoaderHierarchy, Closeable {
private static final Object MISSING_CLASS = new Object();
private final ConcurrentMap<String, Object> loadedClasses = new MapMaker().weakValues().makeMap();
private final ClassLoader parent;
public CachingClassLoader(ClassLoader parent) {
super(parent);
this.parent = parent;
}
@Override
protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
Object cachedValue = loadedClasses.get(name);
if (cachedValue instanceof Class) {
return (Class<?>) cachedValue;
} else if (cachedValue == MISSING_CLASS) {
throw new ClassNotFoundException(name);
}
Class<?> result;
try {
result = super.loadClass(name, resolve);
} catch (ClassNotFoundException e) {
loadedClasses.putIfAbsent(name, MISSING_CLASS);
throw e;
}
loadedClasses.putIfAbsent(name, result);
return result;
}
public void visit(ClassLoaderVisitor visitor) {
visitor.visitSpec(new Spec());
visitor.visitParent(getParent());
}
@Override
public void close() throws IOException {
loadedClasses.clear();
}
public static class Spec extends ClassLoaderSpec {
@Override
public boolean equals(Object obj) {
return obj != null && obj.getClass().equals(Spec.class);
}
@Override
public int hashCode() {
return getClass().getName().hashCode();
}
}
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (!(o instanceof CachingClassLoader)) {
return false;
}
CachingClassLoader that = (CachingClassLoader) o;
return parent.equals(that.parent);
}
public int hashCode() {
return parent.hashCode();
}
}