org.apache.phoenix.pig.hadoop.PhoenixRecordReader.java Source code

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Here is the source code for org.apache.phoenix.pig.hadoop.PhoenixRecordReader.java

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/*
 * Copyright 2010 The Apache Software Foundation
 *
 * 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 maynot 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 applicablelaw 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.pig.hadoop;

import java.io.IOException;
import java.sql.SQLException;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.phoenix.compile.QueryPlan;
import org.apache.phoenix.iterate.ConcatResultIterator;
import org.apache.phoenix.iterate.LookAheadResultIterator;
import org.apache.phoenix.iterate.PeekingResultIterator;
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.pig.PhoenixPigConfiguration;

import com.google.common.base.Preconditions;
import com.google.common.base.Throwables;
import com.google.common.collect.Lists;

/**
 * RecordReader that process the scan and returns PhoenixRecord
 * 
 */
public final class PhoenixRecordReader extends RecordReader<NullWritable, PhoenixRecord> {

    private static final Log LOG = LogFactory.getLog(PhoenixRecordReader.class);
    private final PhoenixPigConfiguration phoenixConfiguration;
    private final QueryPlan queryPlan;
    private final int columnsCount;
    private NullWritable key = NullWritable.get();
    private PhoenixRecord value = null;
    private ResultIterator resultIterator = null;
    private PhoenixResultSet resultSet;

    public PhoenixRecordReader(final PhoenixPigConfiguration pConfiguration, final QueryPlan qPlan)
            throws SQLException {

        Preconditions.checkNotNull(pConfiguration);
        Preconditions.checkNotNull(qPlan);
        this.phoenixConfiguration = pConfiguration;
        this.queryPlan = qPlan;
        this.columnsCount = phoenixConfiguration.getSelectColumnsCount();
    }

    @Override
    public void close() throws IOException {
        if (resultIterator != null) {
            try {
                resultIterator.close();
            } catch (SQLException e) {
                LOG.error(" Error closing resultset.");
            }
        }
    }

    @Override
    public NullWritable getCurrentKey() throws IOException, InterruptedException {
        return key;
    }

    @Override
    public PhoenixRecord getCurrentValue() throws IOException, InterruptedException {
        return value;
    }

    @Override
    public float getProgress() throws IOException, InterruptedException {
        return 0;
    }

    @Override
    public void initialize(InputSplit split, TaskAttemptContext context) throws IOException, InterruptedException {
        final PhoenixInputSplit pSplit = (PhoenixInputSplit) split;
        final List<Scan> scans = pSplit.getScans();
        try {
            List<PeekingResultIterator> iterators = Lists.newArrayListWithExpectedSize(scans.size());
            for (Scan scan : scans) {
                final TableResultIterator tableResultIterator = new TableResultIterator(queryPlan.getContext(),
                        queryPlan.getTableRef(), scan);
                PeekingResultIterator peekingResultIterator = LookAheadResultIterator.wrap(tableResultIterator);
                iterators.add(peekingResultIterator);
            }
            ResultIterator iterator = ConcatResultIterator.newConcatResultIterator(iterators);
            if (queryPlan.getContext().getSequenceManager().getSequenceCount() > 0) {
                iterator = new SequenceResultIterator(iterator, queryPlan.getContext().getSequenceManager());
            }
            this.resultIterator = iterator;
            this.resultSet = new PhoenixResultSet(this.resultIterator, queryPlan.getProjector(),
                    queryPlan.getContext().getStatement());
        } catch (SQLException e) {
            LOG.error(String.format(" Error [%s] initializing PhoenixRecordReader. ", e.getMessage()));
            Throwables.propagate(e);
        }

    }

    @Override
    public boolean nextKeyValue() throws IOException, InterruptedException {
        if (key == null) {
            key = NullWritable.get();
        }
        if (value == null) {
            value = new PhoenixRecord();
        }
        Preconditions.checkNotNull(this.resultSet);
        try {
            if (!resultSet.next()) {
                return false;
            }
            value.read(resultSet, columnsCount);
            return true;
        } catch (SQLException e) {
            LOG.error(String.format(" Error [%s] occurred while iterating over the resultset. ", e.getMessage()));
            Throwables.propagate(e);
        }
        return false;
    }
}