/*
 * 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 com.sun.opends.sdk.util;



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

import org.opends.sdk.ErrorResultException;
import org.opends.sdk.FutureResult;



/**
 * An implementation of {@code FutureResult} which can be used in cases
 * where the result is known in advance, for example, if the result is
 * obtained synchronously.
 *
 * @param <S>
 *          The type of result returned by this future.
 */
public final class CompletedFutureResult<S> implements FutureResult<S>
{
  private final S result;

  private final ErrorResultException errorResult;

  private final int requestID;



  /**
   * Creates a new completed future which will return the provided
   * result and request ID of {@code -1}.
   *
   * @param result
   *          The result, which may be {@code null}.
   */
  public CompletedFutureResult(S result)
  {
    this(result, -1);
  }



  /**
   * Creates a new completed future which will throw the provided error
   * result and request ID of {@code -1}.
   *
   * @param errorResult
   *          The error result.
   * @throws NullPointerException
   *           If {@code errorResult} was {@code null}.
   */
  public CompletedFutureResult(ErrorResultException errorResult)
      throws NullPointerException
  {
    this(errorResult, -1);
  }



  /**
   * Creates a new completed future which will return the provided
   * result and request ID.
   *
   * @param result
   *          The result, which may be {@code null}.
   * @param requestID
   *          The request ID.
   */
  public CompletedFutureResult(S result, int requestID)
  {
    this.result = result;
    this.errorResult = null;
    this.requestID = requestID;
  }



  /**
   * Creates a new completed future which will throw the provided error
   * result and request ID.
   *
   * @param errorResult
   *          The error result.
   * @param requestID
   *          The request ID.
   * @throws NullPointerException
   *           If {@code errorResult} was {@code null}.
   */
  public CompletedFutureResult(ErrorResultException errorResult,
      int requestID) throws NullPointerException
  {
    Validator.ensureNotNull(errorResult);
    this.result = null;
    this.errorResult = errorResult;
    this.requestID = requestID;
  }



  public boolean cancel(boolean mayInterruptIfRunning)
  {
    return false;
  }



  public S get() throws ErrorResultException, InterruptedException
  {
    if (errorResult == null)
    {
      // May be null.
      return result;
    }
    else
    {
      throw errorResult;
    }
  }



  public S get(long timeout, TimeUnit unit)
      throws ErrorResultException, TimeoutException,
      InterruptedException
  {
    return get();
  }



  public int getRequestID()
  {
    return requestID;
  }



  public boolean isCancelled()
  {
    return false;
  }



  public boolean isDone()
  {
    return true;
  }

}