library/src/main/java/com/datatorrent/lib/stream/DevNull.java

/*
 * Copyright (c) 2013 DataTorrent, Inc. ALL Rights Reserved.
 *
 * 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 com.datatorrent.lib.stream;

import com.datatorrent.api.BaseOperator;
import com.datatorrent.api.DefaultInputPort;
import com.datatorrent.api.annotation.Stateless;

/**
 * An implementation of BaseOperator that terminates a stream and does not affect the tuple. 
 * <p>
 * Useful if you want to have a stream for monitoring purpose etc. In future STRAM may simply support a
 * virtual stream and make this operator redundant<br>
 * <br>
 * <b>Port</b>:<br>
 * <b>data</b>: expects K<br>
 * <br>
 * @displayName Dev Null
 * @category Stream
 * @tags debug, terminate
 * @since 0.3.3
 */
@Stateless
public class DevNull<K> extends BaseOperator
{
	/**
	 * Input any data type port.
	 */
	public final transient DefaultInputPort<K> data = new DefaultInputPort<K>()
	{
		@Override
		public void process(K tuple)
		{
			// Does nothing; allows a stream to terminate and therefore be debugged
		}
	};
}