IdentityBolt.java

// Copyright 2016 Twitter. 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.twitter.heron.integration_test.common.bolt;

import java.util.logging.Logger;

import com.twitter.heron.api.bolt.BaseBasicBolt;
import com.twitter.heron.api.bolt.BasicOutputCollector;
import com.twitter.heron.api.topology.OutputFieldsDeclarer;
import com.twitter.heron.api.tuple.Fields;
import com.twitter.heron.api.tuple.Tuple;

public class IdentityBolt extends BaseBasicBolt {
  private static final long serialVersionUID = 2167298598594517481L;
  private static final Logger LOG = Logger.getLogger(IdentityBolt.class.getName());
  private Fields fields;

  public IdentityBolt(Fields fields) {
    this.fields = fields;
  }

  @Override
  public void execute(Tuple input, BasicOutputCollector collector) {
    StringBuilder sb = new StringBuilder();
    for (Object o : input.getValues()) {
      if (sb.length() > 0) {
        sb.append(",");
      }
      sb.append(o.toString());
    }
    LOG.info("Receiving and emitting tuple values: " + sb.toString());
    collector.emit(input.getValues());
  }

  @Override
  public void declareOutputFields(OutputFieldsDeclarer declarer) {
    declarer.declare(fields);
  }
}