Action.java

/*
 * Action.java February 2007
 *
 * Copyright (C) 2007, Niall Gallagher <niallg@users.sf.net>
 *
 * 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.simpleframework.transport.reactor;

import java.nio.channels.SelectableChannel;

/**
 * The <code>Action</code> object is used to represent an action that the
 * distributor is to process. This contains the operation and the required I/O
 * events as an integer bit mask. When an operation is considered ready it will
 * be handed to an executor to execute.
 * 
 * @author Niall Gallagher
 */
interface Action extends Runnable {

    /**
     * This is used to get the expiry for the operation. The expiry represents
     * some static time in the future when the action will expire if it does not
     * become ready. This is used to cancel the operation so that it does not
     * remain in the distributor.
     * 
     * @return the remaining time this operation will wait for
     */
    long getExpiry();

    /**
     * This returns the I/O operations that the action is interested in as an
     * integer bit mask. When any of these operations are ready the distributor
     * will execute the provided operation.
     * 
     * @return the integer bit mask of interested I/O operations
     */
    int getInterest();

    /**
     * This is the <code>SelectableChannel</code> which is used to determine if
     * the operation should be executed. If the channel is ready for a given I/O
     * event it can be run. For instance if the operation is used to perform
     * some form of read operation it can be executed when ready to read data
     * from the channel.
     * 
     * @return this returns the channel used to govern execution
     */
    SelectableChannel getChannel();

    /**
     * This is used to acquire the <code>Operation</code> that is to be executed
     * when the required operations are ready. It is the responsibility of the
     * distributor to invoke the operation.
     * 
     * @return the operation to be executed when it is ready
     */
    Operation getOperation();
}