Java tutorial
/* * Copyright 2013-2014 eBay Software Foundation * * 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 com.kylinolap.job.hadoop.cube; import java.io.IOException; import java.util.HashSet; import com.kylinolap.common.mr.KylinReducer; import org.apache.hadoop.hbase.util.Bytes; import org.apache.hadoop.io.ShortWritable; import org.apache.hadoop.io.Text; import com.kylinolap.common.util.ByteArray; /** * @author yangli9 */ public class FactDistinctColumnsCombiner extends KylinReducer<ShortWritable, Text, ShortWritable, Text> { private Text outputValue = new Text(); @Override protected void setup(Context context) throws IOException { super.publishConfiguration(context.getConfiguration()); } @Override public void reduce(ShortWritable key, Iterable<Text> values, Context context) throws IOException, InterruptedException { HashSet<ByteArray> set = new HashSet<ByteArray>(); for (Text textValue : values) { ByteArray value = new ByteArray(Bytes.copy(textValue.getBytes(), 0, textValue.getLength())); set.add(value); } for (ByteArray value : set) { outputValue.set(value.data); context.write(key, outputValue); } } }