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/*
 * Copyright 2011 The Netty Project
 *
 * The Netty Project licenses this file to you 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 io.netty.handler.traffic;

import java.util.concurrent.Executor;

import io.netty.channel.ChannelHandler.Sharable;
import io.netty.handler.execution.ExecutionHandler;
import io.netty.handler.execution.MemoryAwareThreadPoolExecutor;
import io.netty.handler.execution.OrderedMemoryAwareThreadPoolExecutor;

/**
 * This implementation of the {@link AbstractTrafficShapingHandler} is for global
 * traffic shaping, that is to say a global limitation of the bandwidth, whatever
 * the number of opened channels.


 *
 * The general use should be as follow:

 * 
 * Create your unique GlobalTrafficShapingHandler like:


 * GlobalTrafficShapingHandler myHandler = new GlobalTrafficShapingHandler(executor);


 * executor could be created using Executors.newCachedThreadPool();

 * pipeline.addLast("GLOBAL_TRAFFIC_SHAPING", myHandler);


 *
 * Note that this handler has a Pipeline Coverage of "all" which means only one such handler must be created
 * and shared among all channels as the counter must be shared among all channels.


 *
 * Other arguments can be passed like write or read limitation (in bytes/s where 0 means no limitation)
 * or the check interval (in millisecond) that represents the delay between two computations of the
 * bandwidth and so the call back of the doAccounting method (0 means no accounting at all).


 *
 * A value of 0 means no accounting for checkInterval. If you need traffic shaping but no such accounting,
 * it is recommended to set a positive value, even if it is high since the precision of the
 * Traffic Shaping depends on the period where the traffic is computed. The highest the interval,
 * the less precise the traffic shaping will be. It is suggested as higher value something close
 * to 5 or 10 minutes.

 * 
 * Add it in your pipeline, before a recommended {@link ExecutionHandler} (like
 * {@link OrderedMemoryAwareThreadPoolExecutor} or {@link MemoryAwareThreadPoolExecutor}).

 * pipeline.addLast("GLOBAL_TRAFFIC_SHAPING", myHandler);


 * 
 * When you shutdown your application, release all the external resources like the executor
 * by calling:

 * myHandler.releaseExternalResources();

 * 
 * 


 */
@Sharable
public class GlobalTrafficShapingHandler extends AbstractTrafficShapingHandler {
    /**
     * Create the global TrafficCounter
     */
    void createGlobalTrafficCounter() {
        TrafficCounter tc = new TrafficCounter(this, executor, "GlobalTC",
                checkInterval);
        setTrafficCounter(tc);
        tc.start();
    }

    /**
     * @param executor
     * @param writeLimit
     * @param readLimit
     * @param checkInterval
     */
    public GlobalTrafficShapingHandler(Executor executor, long writeLimit,
            long readLimit, long checkInterval) {
        super(executor, writeLimit, readLimit, checkInterval);
        createGlobalTrafficCounter();
    }

    /**
     * @param executor
     * @param writeLimit
     * @param readLimit
     */
    public GlobalTrafficShapingHandler(Executor executor, long writeLimit,
            long readLimit) {
        super(executor, writeLimit, readLimit);
        createGlobalTrafficCounter();
    }
}