library/src/main/java/org/apache/apex/malhar/lib/io/CollectionMultiConsoleOutputOperator.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 com.datatorrent.lib.io;

import java.util.Collection;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.datatorrent.api.DefaultInputPort;
import com.datatorrent.common.util.BaseOperator;

/**
 * This output operator receives collections as tuples. 
 * The contents of each collection is written out to the container's stdout.
 * <p>
 * This is for specific use case for collection where I want to print each key
 * value pair in different line <br>
 * Mainly to be used for debugging. Users should be careful to not have this
 * node listen to a high throughput stream<br>
 * <br>
 * </p>
 * @displayName Container Stdout Output
 * @category Output
 * @tags output operator
 *
 * @since 0.3.4
 */
@org.apache.hadoop.classification.InterfaceStability.Evolving
public class CollectionMultiConsoleOutputOperator<E> extends BaseOperator
{
  private boolean debug = false;

  public boolean isDebug()
  {
    return debug;
  }

  public void setDebug(boolean debug)
  {
    this.debug = debug;
  }

  private static final Logger logger = LoggerFactory.getLogger(CollectionMultiConsoleOutputOperator.class);

  /**
   * This input port which receives collection tuples.
   */
  public final transient DefaultInputPort<Collection<E>> input = new DefaultInputPort<Collection<E>>()
  {
    @Override
    public void process(Collection<E> t)
    {
      System.out.println("{");

      for (E obj : t) {

        if (!silent) {
          System.out.println(obj.toString());
        }
        if (debug) {
          logger.info(obj.toString());
        }
      }
      System.out.println("}");
    }

  };

  boolean silent = false;

  public boolean isSilent()
  {
    return silent;
  }

  public void setSilent(boolean silent)
  {
    this.silent = silent;
  }
}