AvroBinaryDtailPrinter.java

package com.linkedin.databus2.tools.dtail;
/*
*
* Copyright 2013 LinkedIn Corp. 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.
*
*/

import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;

import org.apache.avro.Schema;
import org.apache.avro.generic.GenericDatumWriter;
import org.apache.avro.generic.GenericRecord;
import org.apache.avro.io.BinaryEncoder;
import org.apache.log4j.Logger;

import com.linkedin.databus.client.DatabusHttpClientImpl;
import com.linkedin.databus.client.pub.ConsumerCallbackResult;


/**
 * An event printer using the standard Avro Binary serialization.
 * */
public class AvroBinaryDtailPrinter extends GenericRecordDtailPrinter
{
  public static final Logger LOG = Logger.getLogger(AvroBinaryDtailPrinter.class);

  private final HashMap<Schema, GenericDatumWriter<GenericRecord>> binWriters;
  private final HashMap<Schema, BinaryEncoder> _binEncoders;

  public AvroBinaryDtailPrinter(DatabusHttpClientImpl client, StaticConfig conf, OutputStream out)
  {
    this(client, conf, out, MetadataOutput.NONE);
  }

  public AvroBinaryDtailPrinter(DatabusHttpClientImpl client, StaticConfig conf, OutputStream out,
                                MetadataOutput metadata)
  {
    super(client, conf, out, metadata);
    binWriters = new HashMap<Schema, GenericDatumWriter<GenericRecord>>(5);
    _binEncoders = new HashMap<Schema, BinaryEncoder>(5);
  }

  /**
   * @see com.linkedin.databus2.tools.dtail.GenericRecordDtailPrinter#printGenericRecord(org.apache.avro.generic.GenericRecord)
   */
  @Override
  public ConsumerCallbackResult printGenericRecord(GenericRecord r)
  {
    ConsumerCallbackResult result = ConsumerCallbackResult.SUCCESS;
    try
    {

      BinaryEncoder binEnc = _binEncoders.get(r.getSchema());
      if (null == binEnc)
      {
        binEnc = new BinaryEncoder(_out);
        _binEncoders.put(r.getSchema(), binEnc);
      }

      GenericDatumWriter<GenericRecord> datumWriter = binWriters.get(r.getSchema());
      if (null == datumWriter)
      {
        datumWriter = new GenericDatumWriter<GenericRecord>(r.getSchema());
        binWriters.put(r.getSchema(), datumWriter);
      }

      datumWriter.write(r, binEnc);
      binEnc.flush();
      _out.write('\n');
    }
    catch (RuntimeException re)
    {
      LOG.error("event dump error: " + re.getMessage(), re);
      result = ConsumerCallbackResult.ERROR;
    }
    catch (IOException ioe)
    {
      LOG.error("event dump error: " + ioe.getMessage(), ioe);
      result = ConsumerCallbackResult.ERROR;
    }
    return result;
  }

}