/*
* Copyright 2013-2014 the original author or authors.
*
* 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 org.springframework.data.hadoop.store.dataset;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.kitesdk.data.Dataset;
import org.kitesdk.data.DatasetWriter;
import org.kitesdk.data.Formats;
import org.springframework.data.hadoop.store.StoreException;
import org.springframework.util.Assert;
import java.io.IOException;
/**
* A {@code DataStoreWriter} for writing Datasets using the Avro format.
*
* @author Thomas Risberg
*/
public class AvroPojoDatasetStoreWriter<T> extends AbstractDatasetStoreWriter<T> {
private final static Log log = LogFactory.getLog(AvroPojoDatasetStoreWriter.class);
protected volatile DatasetWriter<T> writer;
private final Object monitor = new Object();
/**
* Instantiates a new {@code DataStoreWriter} for writing Avro records to a {@code org.kitesdk.data.Dataset}.
*
* @param entityClass the {@code Class} that the writer will write to the Dataset
* @param datasetRepositoryFactory the {@code DatasetRepositoryFactory} to be used for the writer
*/
public AvroPojoDatasetStoreWriter(Class<T> entityClass, DatasetRepositoryFactory datasetRepositoryFactory) {
this(entityClass, datasetRepositoryFactory, new DatasetDefinition(entityClass, false, Formats.AVRO.getName()));
}
/**
* Instantiates a new {@code DataStoreWriter} for writing Avro records to a {@code org.kitesdk.data.Dataset}.
*
* @param entityClass the {@code Class} that the writer will write to the Dataset
* @param datasetRepositoryFactory the {@code DatasetRepositoryFactory} to be used for the writer
* @param datasetDefinition the {@code DatasetDefinition} to be used for the writer
*/
public AvroPojoDatasetStoreWriter(Class<T> entityClass, DatasetRepositoryFactory datasetRepositoryFactory, DatasetDefinition datasetDefinition) {
super(entityClass, datasetRepositoryFactory, datasetDefinition);
}
@Override
public void write(T entity) throws IOException {
Assert.notNull(entity, "Entity to be written can't be 'null'.");
if (!entity.getClass().equals(entityClass)) {
throw new IllegalArgumentException("Entity to write is of class " + entity.getClass().getName() +
". Expected " + entityClass.getName());
}
synchronized (monitor) {
if (writer == null) {
if (Formats.AVRO.getName().equals(datasetDefinition.getFormat().getName())) {
Dataset<T> dataset =
DatasetUtils.getOrCreateDataset(datasetRepositoryFactory, datasetDefinition, entityClass, entityClass);
writer = dataset.newWriter();
} else {
throw new StoreException("Invalid format " + datasetDefinition.getFormat() +
" specified, you must use 'avro' with " + this.getClass().getSimpleName() + ".");
}
}
}
writer.write(entity);
}
@Override
public void flush() throws IOException {
if (log.isDebugEnabled()) {
log.debug("Flushing writer " + writer);
}
if (writer != null) {
writer.flush();
}
}
@Override
public void close() throws IOException {
if (log.isDebugEnabled()) {
log.debug("Closing writer " + writer);
}
if (writer != null) {
writer.close();
}
}
}