/**
* 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 org.apache.gora.avro.store;
import java.io.IOException;
import org.apache.avro.file.DataFileReader;
import org.apache.avro.file.DataFileWriter;
import org.apache.gora.avro.mapreduce.FsInput;
import org.apache.gora.avro.query.DataFileAvroResult;
import org.apache.gora.persistency.impl.PersistentBase;
import org.apache.gora.query.Query;
import org.apache.gora.query.Result;
import org.apache.gora.query.impl.FileSplitPartitionQuery;
import org.apache.gora.util.OperationNotSupportedException;
import org.apache.hadoop.fs.Path;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* DataFileAvroStore is file based store which uses Avro's
* DataFile{Writer,Reader}'s as a backend. This datastore supports
* mapreduce.
*/
public class DataFileAvroStore<K, T extends PersistentBase> extends AvroStore<K, T> {
public static final Logger LOG = LoggerFactory.getLogger(AvroStore.class);
public DataFileAvroStore() {
}
private DataFileWriter<T> writer;
@Override
public T get(K key, String[] fields) {
throw new OperationNotSupportedException(
"Avro DataFile's does not support indexed retrieval");
};
@Override
public void put(K key, T obj) {
try{
getWriter().append(obj);
} catch(IOException ex){
LOG.error(ex.getMessage());
LOG.error(ex.getStackTrace().toString());
}
};
private DataFileWriter<T> getWriter() throws IOException {
if(writer == null) {
writer = new DataFileWriter<T>(getDatumWriter());
writer.create(schema, getOrCreateOutputStream());
}
return writer;
}
@Override
protected Result<K, T> executeQuery(Query<K, T> query) {
try{
return new DataFileAvroResult<K, T>(this, query
, createReader(createFsInput()));
} catch(IOException ex){
LOG.error(ex.getMessage());
LOG.error(ex.getStackTrace().toString());
return null;
}
}
@Override
protected Result<K,T> executePartial(FileSplitPartitionQuery<K,T> query) {
try{
FsInput fsInput = createFsInput();
DataFileReader<T> reader = createReader(fsInput);
return new DataFileAvroResult<K, T>(this, query, reader, fsInput
, query.getStart(), query.getLength());
} catch(IOException ex){
LOG.error(ex.getMessage());
LOG.error(ex.getStackTrace().toString());
return null;
}
}
private DataFileReader<T> createReader(FsInput fsInput) throws IOException {
return new DataFileReader<T>(fsInput, getDatumReader());
}
private FsInput createFsInput() throws IOException {
Path path = new Path(getInputPath());
return new FsInput(path, getConf());
}
@Override
public void flush() {
try{
super.flush();
if(writer != null) {
writer.flush();
}
} catch(IOException ex){
LOG.error(ex.getMessage());
LOG.error(ex.getStackTrace().toString());
}
}
@Override
public void close() {
try{
if(writer != null)
writer.close(); //hadoop 0.20.2 HDFS streams do not allow
//to close twice, so close the writer first
writer = null;
super.close();
} catch(IOException ex){
LOG.error(ex.getMessage());
LOG.error(ex.getStackTrace().toString());
}
}
}