/***********************************************************************************************************************
 *
 * Copyright (C) 2010 by the Stratosphere project (http://stratosphere.eu)
 *
 * 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 eu.stratosphere.nephele.services.iomanager;

import java.io.IOException;


/**
 * Basic interface that I/O requests that are sent to the threads of the I/O manager need to implement.
 *
 * @author Stephan Ewen (stephan.ewen@tu-berlin.de)
 */
interface IORequest
{
	/**
	 * Method that is called by the target I/O thread after the request has been processed.
	 * 
	 * @param ioex The exception that occurred while processing the I/O request. Is <tt>null</tt> if everything
	 *             was fine.
	 */
	public void requestDone(IOException ioex);
}


/**
 * Interface for I/O requests that are handled by the IOManager's reading thread. 
 */
interface ReadRequest extends IORequest
{
	/**
	 * Called by the target I/O thread to perform the actual reading operation.
	 * 
	 * @throws IOException My be thrown by the method to indicate an I/O problem.
	 */
	public void read() throws IOException;
}


/**
 * Interface for I/O requests that are handled by the IOManager's writing thread.
 */
interface WriteRequest extends IORequest
{
	/**
	 * Called by the target I/O thread to perform the actual writing operation.
	 * 
	 * @throws IOException My be thrown by the method to indicate an I/O problem.
	 */
	public void write() throws IOException;
}
