/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * particular file as subject to the "Classpath" exception as provided

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 */

package sun.nio.ch;

import java.util.concurrent.Future;

import java.util.concurrent.TimeUnit;

import java.util.concurrent.ExecutionException;

import java.io.IOException;

/**

 * A Future representing the result of an I/O operation that has already

 * completed.

 */

final class CompletedFuture<V> implements Future<V> {

    private final V result;

    private final Throwable exc;

    private CompletedFuture(V result, Throwable exc) {

        this.result = result;

        this.exc = exc;

    }

    @SuppressWarnings("unchecked")

    static <V> CompletedFuture<V> withResult(V result) {

        return new CompletedFuture<V>(result, null);

    }

    @SuppressWarnings("unchecked")

    static <V> CompletedFuture<V> withFailure(Throwable exc) {

        // exception must be IOException or SecurityException

        if (!(exc instanceof IOException) && !(exc instanceof SecurityException))

            exc = new IOException(exc);

        return new CompletedFuture(null, exc);

    }

    @SuppressWarnings("unchecked")

    static <V> CompletedFuture<V> withResult(V result, Throwable exc) {

        if (exc == null) {

            return withResult(result);

        } else {

            return withFailure(exc);

        }

    }

    @Override

    public V get() throws ExecutionException {

        if (exc != null)

            throw new ExecutionException(exc);

        return result;

    }

    @Override

    public V get(long timeout, TimeUnit unit) throws ExecutionException {

        if (unit == null)

            throw new NullPointerException();

        if (exc != null)

            throw new ExecutionException(exc);

        return result;

    }

    @Override

    public boolean isCancelled() {

        return false;

    }

    @Override

    public boolean isDone() {

        return true;

    }

    @Override

    public boolean cancel(boolean mayInterruptIfRunning) {

        return false;

    }

}