org.eclipse.jetty.util.Callback Maven / Gradle / Ivy
//
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// Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
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// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
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/*
* Copyright (c) 2012 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.eclipse.jetty.util;
import org.eclipse.jetty.util.log.Log;
/**
* A callback abstraction that handles completed/failed events of asynchronous operations.
*
* Semantically this is equivalent to an optimise Promise<Void>, but callback is a more meaningful
* name than EmptyPromise
*/
public interface Callback
{
/**
* Callback invoked when the operation completes.
*
* @see #failed(Throwable)
*/
public abstract void succeeded();
/**
* Callback invoked when the operation fails.
* @param x the reason for the operation failure
*/
public void failed(Throwable x);
/**
* Empty implementation of {@link Callback}
*/
public static class Adapter implements Callback
{
@Override
public void succeeded()
{
}
@Override
public void failed(Throwable x)
{
Log.getLogger(this.getClass()).warn(x);
}
}
}