/*
* 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.giraph.hive.primitives;
import org.apache.giraph.conf.ImmutableClassesGiraphConfiguration;
import org.apache.giraph.conf.StrConfOption;
import org.apache.giraph.graph.GraphType;
import org.apache.giraph.hive.values.HiveValueWriter;
import org.apache.giraph.types.WritableUnwrapper;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Writable;
import com.facebook.hiveio.record.HiveWritableRecord;
import com.facebook.hiveio.schema.HiveTableSchema;
import com.google.common.base.Preconditions;
import static org.apache.giraph.hive.common.HiveUtils.columnIndexOrThrow;
import static org.apache.giraph.types.WritableUnwrappers.lookup;
/**
* Writer for graph values (IVEMM) from Hive with known types
*
* @param <W> Graph user type (IVEMM)
*/
public class PrimitiveValueWriter<W extends Writable>
implements HiveValueWriter<W> {
/** Hive column index */
private final int columnIndex;
/** {@link WritableUnwrapper} for Hive column to Giraph Writable */
private final WritableUnwrapper<W, Object> writableUnwrapper;
/**
* Constructor
*
* @param columnIndex column index
* @param writableUnwrapper JavaWritableConverter
*/
public PrimitiveValueWriter(int columnIndex,
WritableUnwrapper<W, Object> writableUnwrapper) {
Preconditions.checkNotNull(writableUnwrapper);
this.columnIndex = columnIndex;
this.writableUnwrapper = writableUnwrapper;
}
/**
* Create from Configuration with column name and Schema
*
* @param <T> Graph Type (IVEMM)
* @param conf Configuration
* @param columnOption StrConfOption for column name
* @param schema HiveTableSchema
* @param graphType GraphType
* @return TypedVertexValueReader
*/
public static <T extends Writable> HiveValueWriter<T> create(
ImmutableClassesGiraphConfiguration conf, StrConfOption columnOption,
HiveTableSchema schema, GraphType graphType) {
Class<T> valueClass = graphType.get(conf);
if (NullWritable.class.isAssignableFrom(valueClass)) {
return HiveValueWriter.Null.get();
}
int columnIndex = columnIndexOrThrow(schema, conf, columnOption);
Class hiveClass = schema.columnType(columnIndex).javaClass();
WritableUnwrapper unwrapper = lookup(valueClass, hiveClass);
return new PrimitiveValueWriter(columnIndex, unwrapper);
}
@Override
public void write(W value, HiveWritableRecord record) {
Object object = writableUnwrapper.unwrap(value);
record.set(columnIndex, object);
}
}