/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE
 * or https://OpenDS.dev.java.net/OpenDS.LICENSE.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE.  If applicable,
 * add the following below this CDDL HEADER, with the fields enclosed
 * by brackets "[]" replaced with your own identifying information:
 *      Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 *
 *      Copyright 2009 Sun Microsystems, Inc.
 */

package org.opends.sdk;



import java.util.concurrent.CancellationException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

import org.opends.sdk.responses.Result;



/**
 * A handle which can be used to retrieve the Result of an asynchronous
 * Request.
 * 
 * @param <S>
 *          The type of result returned by this future.
 */
public interface ResultFuture<S extends Result> extends Future<S>
{
  /**
   * Attempts to cancel the request. This attempt will fail if the
   * request has already completed or has already been cancelled. If
   * successful, then cancellation results in an abandon or cancel
   * request (if configured) being sent to the server.
   * <p>
   * After this method returns, subsequent calls to {@link #isDone} will
   * always return {@code true}. Subsequent calls to
   * {@link #isCancelled} will always return {@code true} if this method
   * returned {@code true}.
   * 
   * @param mayInterruptIfRunning
   *          {@code true} if the thread executing executing the
   *          response handler should be interrupted; otherwise,
   *          in-progress response handlers are allowed to complete.
   * @return {@code false} if the request could not be cancelled,
   *         typically because it has already completed normally;
   *         {@code true} otherwise.
   */
  boolean cancel(boolean mayInterruptIfRunning);



  /**
   * Waits if necessary for the request to complete, and then returns
   * the result if the request succeeded. If the request failed (i.e. a
   * non-successful result code was obtained) then the result is thrown
   * as an {@link ErrorResultException}.
   * 
   * @return The result, but only if the result code indicates that the
   *         request succeeded.
   * @throws CancellationException
   *           If the request was cancelled using a call to
   *           {@link #cancel}.
   * @throws ErrorResultException
   *           If the result code indicates that the request failed for
   *           some reason.
   * @throws InterruptedException
   *           If the current thread was interrupted while waiting.
   */
  S get() throws InterruptedException, ErrorResultException;



  /**
   * Waits if necessary for at most the given time for the request to
   * complete, and then returns the result if the request succeeded. If
   * the request failed (i.e. a non-successful result code was obtained)
   * then the result is thrown as an {@link ErrorResultException}.
   * 
   * @param timeout
   *          The maximum time to wait.
   * @param unit
   *          The time unit of the timeout argument.
   * @return The result, but only if the result code indicates that the
   *         request succeeded.
   * @throws CancellationException
   *           If the request was cancelled using a call to
   *           {@link #cancel}.
   * @throws ErrorResultException
   *           If the result code indicates that the request failed for
   *           some reason.
   * @throws InterruptedException
   *           If the current thread was interrupted while waiting.
   * @throws TimeoutException
   *           If the wait timed out.
   */
  S get(long timeout, TimeUnit unit) throws InterruptedException,
      TimeoutException, ErrorResultException;



  /**
   * Returns the message ID of the request.
   * 
   * @return The message ID.
   */
  int getMessageID();



  /**
   * Returns {@code true} if the request was cancelled before it
   * completed normally.
   * 
   * @return {@code true} if the request was cancelled before it
   *         completed normally, otherwise {@code false}.
   */
  boolean isCancelled();



  /**
   * Returns {@code true} if the request has completed.
   * <p>
   * Completion may be due to normal termination, an exception, or
   * cancellation. In all of these cases, this method will return
   * {@code true}.
   * 
   * @return {@code true} if the request has completed, otherwise
   *         {@code false}.
   */
  boolean isDone();
}