KafkaSourceStreamReader.java

package com.neverwinterdp.scribengin.storage.kafka.source;

import java.util.ArrayList;
import java.util.List;

import kafka.javaapi.PartitionMetadata;

import com.neverwinterdp.kafka.consumer.KafkaPartitionReader;
import com.neverwinterdp.scribengin.Record;
import com.neverwinterdp.scribengin.storage.StreamDescriptor;
import com.neverwinterdp.scribengin.storage.source.CommitPoint;
import com.neverwinterdp.scribengin.storage.source.SourceStreamReader;

public class KafkaSourceStreamReader implements SourceStreamReader {
  private StreamDescriptor descriptor;
  private KafkaPartitionReader partitionReader ;
  private CommitPoint lastCommitInfo ;
  
  public KafkaSourceStreamReader(StreamDescriptor descriptor, PartitionMetadata partitionMetadata) {
    this.descriptor = descriptor;
    this.partitionReader = 
        new KafkaPartitionReader(descriptor.attribute("name"), descriptor.attribute("zk.connect"), descriptor.attribute("topic"), partitionMetadata);
  }
  
  @Override
  public String getName() { return descriptor.attribute("name"); }

  @Override
  public Record next() throws Exception {
    return partitionReader.nextAs(Record.class);
  }

  @Override
  public Record[] next(int size) throws Exception {
    List<Record> holder = new ArrayList<Record>();
    Record[] array = new Record[holder.size()];
    return holder.toArray(array);
  }

  @Override
  public void rollback() throws Exception {
    throw new Exception("To implement") ;
  }

  @Override
  public void prepareCommit() throws Exception {
    //TODO: implement 2 phases commit correctly
  }

  @Override
  public void completeCommit() throws Exception {
    //TODO: implement 2 phases commit correctly
    partitionReader.commit();
  }
  
  @Override
  public void commit() throws Exception {
    try {
      prepareCommit() ;
      completeCommit() ;
    } catch(Exception ex) {
      rollback();
      throw ex;
    }
  }
  
  public CommitPoint getLastCommitInfo() { return this.lastCommitInfo ; }
  
  @Override
  public void close() throws Exception {
  }
 
}