samoa-flink/src/main/java/org/apache/samoa/flink/topology/impl/FlinkComponent.java

package org.apache.samoa.flink.topology.impl;

/*
 * #%L
 * SAMOA
 * %%
 * Copyright (C) 2014 - 2015 Apache Software Foundation
 * %%
 * 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.
 * #L%
 */



import org.apache.flink.streaming.api.datastream.DataStream;

/**
 * Common interface of FlinkEntranceProcessingItem and FlinkProcessingItem
 */
public interface FlinkComponent {

	/**
	 * An initiation of the node. It should create the right invokables and apply the appropriate
	 * stream transformations
	 */
	public void initialise();

	/**
	 * This check is needed in order to determine whether all requirements for a Flink Component 
	 * (DataStream) are satisfied in order to initialise it. This is necessary in this integration
	 * since Flink Streaming applies eager datastream generation based on transformations.
	 * 
	 * @return 
	 */
	public boolean canBeInitialised();

	/**
	 * 
	 * @return
	 */
	public boolean isInitialised();

	/**
	 * The wrapped Flink DataStream generated by this Flink component. Mind that the component 
	 * should first be initialised in order to have a generated DataStream
	 * 
	 * @return
	 */
	public DataStream<SamoaType> getOutStream();

	/**
	 * A unique component id
	 * 
	 * @return
	 */
	public int getComponentId();

}