lang/java/reef-wake/wake/src/main/java/org/apache/reef/wake/rx/DynamicObservable.java

/*
 * 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;

/**
 * Defines a "dynamically configured" provider for push-based notification.
 * Observers can be dynamically subscribed at run time.
 *
 * @param <T> type
 */
public interface DynamicObservable<T> extends Observable {

  /**
   * Subscribes the observer to this observable object.
   *
   * @param o the observer
   * @return a subscription handle
   */
  AutoCloseable subscribe(Observer<T> o);
}