Java tutorial
/* * 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.phoenix.hive; import com.google.common.base.Preconditions; import com.google.common.base.Throwables; import java.io.IOException; import java.io.PrintStream; import java.sql.SQLException; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.hbase.client.Scan; import org.apache.hadoop.io.NullWritable; import org.apache.hadoop.mapred.InputSplit; import org.apache.hadoop.mapreduce.TaskAttemptContext; import org.apache.hadoop.mapreduce.lib.db.DBWritable; import org.apache.hadoop.util.ReflectionUtils; import org.apache.phoenix.compile.QueryPlan; import org.apache.phoenix.compile.ScanRanges; import org.apache.phoenix.compile.SequenceManager; import org.apache.phoenix.compile.StatementContext; import org.apache.phoenix.iterate.ResultIterator; import org.apache.phoenix.iterate.SequenceResultIterator; import org.apache.phoenix.iterate.TableResultIterator; import org.apache.phoenix.jdbc.PhoenixResultSet; import org.apache.phoenix.mapreduce.PhoenixRecordReader; import org.apache.phoenix.query.KeyRange; import org.apache.phoenix.util.ScanUtil; /** * HivePhoenixRecordReader * implements mapred as well for hive needs * * @version 1.0 * @since 2015-02-08 */ public class HivePhoenixRecordReader<T extends DBWritable> extends PhoenixRecordReader<T> implements org.apache.hadoop.mapred.RecordReader<NullWritable, T> { private static final Log LOG = LogFactory.getLog(HivePhoenixRecordReader.class); private final Configuration configuration; private final QueryPlan queryPlan; private NullWritable key = NullWritable.get(); private T value = null; private Class<T> inputClass; private ResultIterator resultIterator = null; private PhoenixResultSet resultSet; public HivePhoenixRecordReader(Class<T> inputClass, Configuration configuration, QueryPlan queryPlan) { super(inputClass, configuration, queryPlan); Preconditions.checkNotNull(configuration); Preconditions.checkNotNull(queryPlan); this.inputClass = inputClass; this.configuration = configuration; this.queryPlan = queryPlan; } /* public NullWritable getCurrentKey() throws IOException, InterruptedException { return this.key; } public T getCurrentValue() throws IOException, InterruptedException { return this.value; }*/ public float getProgress() { return 0.0F; } public void init(InputSplit split) throws IOException, InterruptedException { HivePhoenixInputSplit pSplit = (HivePhoenixInputSplit) split; KeyRange keyRange = pSplit.getKeyRange(); Scan splitScan = this.queryPlan.getContext().getScan(); Scan scan = new Scan(splitScan); ScanUtil.intersectScanRange(scan, keyRange.getLowerRange(), keyRange.getUpperRange(), this.queryPlan.getContext().getScanRanges().useSkipScanFilter()); try { TableResultIterator tableResultIterator = new TableResultIterator(this.queryPlan.getContext(), this.queryPlan.getTableRef(), scan); if (this.queryPlan.getContext().getSequenceManager().getSequenceCount() > 0) this.resultIterator = new SequenceResultIterator(tableResultIterator, this.queryPlan.getContext().getSequenceManager()); else { this.resultIterator = tableResultIterator; } this.resultSet = new PhoenixResultSet(this.resultIterator, this.queryPlan.getProjector(), this.queryPlan.getContext().getStatement()); } catch (SQLException e) { LOG.error(String.format(" Error [%s] initializing PhoenixRecordReader. ", new Object[] { e.getMessage() })); Throwables.propagate(e); } } /*public boolean nextKeyValue() throws IOException, InterruptedException { if (this.key == null) { this.key = NullWritable.get(); } if (this.value == null) { this.value = (T) ((DBWritable) ReflectionUtils.newInstance(this.inputClass, this.configuration)); } Preconditions.checkNotNull(this.resultSet); try { if (!this.resultSet.next()) { return false; } this.value.readFields(this.resultSet); return true; } catch (SQLException e) { LOG.error(String.format(" Error [%s] occurred while iterating over the resultset. ", new Object[] { e.getMessage() })); Throwables.propagate(e); } return false; }*/ public boolean next(NullWritable key, T val) throws IOException { if (key == null) { key = NullWritable.get(); } if (this.value == null) { this.value = (T) ((DBWritable) ReflectionUtils.newInstance(this.inputClass, this.configuration)); } Preconditions.checkNotNull(this.resultSet); try { if (!this.resultSet.next()) { return false; } this.value.readFields(this.resultSet); LOG.debug("PhoenixRecordReader resultset size" + this.resultSet.getFetchSize()); return true; } catch (SQLException e) { LOG.error(String.format(" Error [%s] occurred while iterating over the resultset. ", new Object[] { e.getMessage() })); Throwables.propagate(e); } return false; } public NullWritable createKey() { return this.key; } public T createValue() { this.value = (T) ((DBWritable) ReflectionUtils.newInstance(this.inputClass, this.configuration)); return this.value; } public long getPos() throws IOException { return 0L; } }