/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.hadoop.cascading;
import java.util.List;
import org.apache.hadoop.io.Writable;
import org.elasticsearch.hadoop.mr.WritableValueWriter;
import org.elasticsearch.hadoop.serialization.Generator;
import org.elasticsearch.hadoop.serialization.builder.JdkValueWriter;
import org.elasticsearch.hadoop.serialization.builder.ValueWriter;
import cascading.scheme.SinkCall;
import cascading.tuple.Tuple;
/**
* Basic delegate around {@link JdkValueWriter} that handles the unwraping of {@link SinkCall}
*/
public class CascadingValueWriter implements ValueWriter<SinkCall<Object[], ?>> {
private final ValueWriter<Object> jdkWriter;
private final ValueWriter<Writable> writableWriter;
public CascadingValueWriter() {
this(false);
}
public CascadingValueWriter(boolean writeUnknownTypes) {
jdkWriter = new JdkValueWriter(writeUnknownTypes);
writableWriter = new WritableValueWriter(writeUnknownTypes);
}
@SuppressWarnings("unchecked")
@Override
public boolean write(SinkCall<Object[], ?> sinkCall, Generator generator) {
Tuple tuple = CascadingUtils.coerceToString(sinkCall);
// consider names (in case of aliases these are already applied)
List<String> names = (List<String>) sinkCall.getContext()[0];
generator.writeBeginObject();
for (int i = 0; i < tuple.size(); i++) {
String name = (i < names.size() ? names.get(i) : "tuple" + i);
generator.writeFieldName(name);
Object object = tuple.getObject(i);
if (!jdkWriter.write(object, generator)) {
if (!(object instanceof Writable) || !writableWriter.write((Writable) object, generator)) {
return false;
}
}
}
generator.writeEndObject();
return true;
}
}