/*
* Copyright 2009 Thomas Bocek
*
* 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 net.tomp2p.futures;
/**
* Represents the result of an asynchronous operation.
*
* @author Thomas Bocek
*/
public interface BaseFuture extends Cancel {
/**
* The first state is always INIT and will always end in either OK, FAILED, or CANCEl.
*/
public enum FutureType {
INIT, OK, FAILED, CANCEL
};
/**
* Wait for the asynchronous operation to end.
*
* @return this
* @throws InterruptedException
* if thread is interrupted
*/
BaseFuture await() throws InterruptedException;
/**
* Wait for the asynchronous operation to end with the specified timeout.
*
* @param timeoutMillis
* time to wait at most
* @return true if the operation is finished.
* @throws InterruptedException
* if thread is interrupted
*/
boolean await(long timeoutMillis) throws InterruptedException;
/**
* Wait for the asynchronous operation to end without interruption.
*
* @return this
*/
BaseFuture awaitUninterruptibly();
/**
* Wait for the asynchronous operation to end with the specified timeout without interruption.
*
* @param timeoutMillis
* to wait at most
* @return true if the operation is finished.
*/
boolean awaitUninterruptibly(long timeoutMillis);
/**
* Checks if the asynchronous operation is finished.
*
* @return true if operation is finished
*/
boolean isCompleted();
/**
* Returns the opposite of isFailed (returns !isFailed). Use this method if you are an optimist ;) otherwise use
* isFailed
*
* @return true if operation succeeded, false if there was no reply
*/
boolean isSuccess();
/**
* Checks if operation has failed. As this is a P2P network, where peers can fail at any time, a failure is seen as
* a "normal" event. Thus, no exception is thrown.
*
* @return true if operation failed, which means the node did not reply. A get(key) operation on a node that does
* not have the key, returns false with this method as a response has been send.
*/
boolean isFailed();
/**
* Sets the failed flag to true and the completed flag to true. This will notify listeners and set the reason
*
* @param reason
* The reason of failure
* @return this
*/
BaseFuture failed(String reason);
/**
* Sets the failed flag to true and the completed flag to true. This will notify listeners and set the reason based
* on the origin BaseFuture.
*
* @param origin
* The origin of failure
* @return this
*/
BaseFuture failed(BaseFuture origin);
/**
* Sets the failed flag to true and the completed flag to true. This will notify listeners and append the reason
* based on the origin BaseFuture.
*
* @param reason
* The reason of failure
* @param origin
* The origin of failure
* @return this
*/
BaseFuture failed(String reason, BaseFuture origin);
/**
* Sets the failed flag to true and the completed flag to true. This will notify listeners and append the reason
* based on the origin BaseFuture.
*
* @param t
* The stack trace where the failure happened
* @return this
*/
BaseFuture failed(final Throwable t);
/**
* Sets the failed flag to true and the completed flag to true. This will notify listeners and append the reason
* based on the origin BaseFuture.
*
* @param reason
* The reason of failure
* @param t
* The stack trace where the failure happened
* @return this
*/
BaseFuture failed(final String reason, final Throwable t);
/**
* The default failed reason is Unknown.
*
* @return Returns the reason why a future failed.
*/
String failedReason();
/**
* If the type is not OK, then something unexpected happened.
*
* @return The fail type
*/
FutureType type();
/**
* Waits until the operation is complete and all the listener finished. This may include the release of resources.
*
* @return this
* @throws InterruptedException
* If interrupted from outside
*/
BaseFuture awaitListeners() throws InterruptedException;
/**
* Waits uninterruptedly until the operation is complete and all the listener finished. This may include the release of resources.
*
* @return this
*/
BaseFuture awaitListenersUninterruptibly();
/**
* Adds a listener which is notified when the state of this future changes. All notifications are performed in a
* thread, which means that this method returns immediately. If a future is complete, then all listeners are called
* and after that, the listener list is cleared, so there is no need to call removeListener if a future has been
* completed.
*
* Be aware that the order of the listeners cannot be guaranteed.
*
* @param listener
* The listener extends the BaseFuture
* @return this
*/
BaseFuture addListener(BaseFutureListener<? extends BaseFuture> listener);
/**
* Removes a listener which is notified when the state of this future changes. If a future is complete, then all
* listeners are called and after that, the listener list is cleared, so there is no need to call removeListener if
* a future has been completed. The listener can be called from the caller thread if the future is already finished
* or from a different thread if the future is not ready yet.
*
* @param listener
* The listener extends the BaseFuture
* @return this
*/
BaseFuture removeListener(BaseFutureListener<? extends BaseFuture> listener);
/**
* Set a cancel callback to this future, which is called when cancel is executed. Triggering a cancel does not
* finish this future.
*
* @param cancel
* The cancel listener
* @return this
*/
BaseFuture setCancel(Cancel cancel);
boolean isCanceled();
}