com.google.inject.internal.DelegatingInvocationHandler Maven / Gradle / Ivy
/*
* Copyright (C) 2009 Google Inc.
*
* 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 com.google.inject.internal;
import com.google.common.base.Preconditions;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
class DelegatingInvocationHandler implements InvocationHandler {
private volatile boolean initialized;
private T delegate;
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
try {
// checking volatile field for synchronization
Preconditions.checkState(
initialized,
"This is a proxy used to support"
+ " circular references. The object we're"
+ " proxying is not constructed yet. Please wait until after"
+ " injection has completed to use this object.");
Preconditions.checkNotNull(
delegate,
"This is a proxy used to support"
+ " circular references. The object we're "
+ " proxying is initialized to null."
+ " No methods can be called.");
// TODO: method.setAccessible(true); ?
// this would fix visibility errors when we proxy a
// non-public interface.
return method.invoke(delegate, args);
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
} catch (IllegalArgumentException e) {
throw new RuntimeException(e);
} catch (InvocationTargetException e) {
throw e.getTargetException();
}
}
void setDelegate(T delegate) {
this.delegate = delegate;
initialized = true;
}
}