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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.reef.wake.rx;
/**
* Provides a mechanism for receiving push-based notifications. Implicit
* contract: zero or more calls of onNext, if a sequence terminates, it is
* terminated by onError or onCompleted in T
*
* @param <T>
*/
public interface Observer<T> {
/**
* Provides the observer with new data.
*
* @param value
*/
void onNext(final T value);
/**
* Notifies the observer that the provider has experienced an error
* condition.
*
* @param error
*/
void onError(final Exception error);
/**
* Notifies the observer that the provider has finished sending push-based
* notifications.
*/
void onCompleted();
}