org.apache.sqoop.mapreduce.hcat.SqoopHCatRecordReader.java Source code

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Here is the source code for org.apache.sqoop.mapreduce.hcat.SqoopHCatRecordReader.java

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/**
 * 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.sqoop.mapreduce.hcat;

import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hcatalog.data.HCatRecord;

/**
 * A Record Reader that can combine underlying splits.
 */
public class SqoopHCatRecordReader extends RecordReader<WritableComparable, HCatRecord> {
    private final SqoopHCatExportFormat hCatExportFormat;
    private SqoopHCatInputSplit hCatSplit;
    private TaskAttemptContext context;
    private int subIndex;
    private long progress;

    private RecordReader<WritableComparable, HCatRecord> curReader;

    public static final Log LOG = LogFactory.getLog(SqoopHCatRecordReader.class.getName());

    public SqoopHCatRecordReader(final InputSplit split, final TaskAttemptContext context,
            final SqoopHCatExportFormat inputFormat) throws IOException {
        this.hCatSplit = (SqoopHCatInputSplit) split;
        this.context = context;
        this.subIndex = 0;
        this.curReader = null;
        this.progress = 0L;
        this.hCatExportFormat = inputFormat;

        initNextRecordReader();
    }

    @Override
    public void initialize(final InputSplit split, final TaskAttemptContext ctxt)
            throws IOException, InterruptedException {
        this.hCatSplit = (SqoopHCatInputSplit) split;
        this.context = ctxt;

        if (null != this.curReader) {
            this.curReader.initialize(((SqoopHCatInputSplit) split).get(0), context);
        }
    }

    @Override
    public boolean nextKeyValue() throws IOException, InterruptedException {
        while (this.curReader == null || !this.curReader.nextKeyValue()) {
            if (!initNextRecordReader()) {
                return false;
            }
        }
        return true;
    }

    @Override
    public WritableComparable getCurrentKey() throws IOException, InterruptedException {
        return this.curReader.getCurrentKey();
    }

    @Override
    public HCatRecord getCurrentValue() throws IOException, InterruptedException {
        return this.curReader.getCurrentValue();
    }

    @Override
    public void close() throws IOException {
        if (this.curReader != null) {
            this.curReader.close();
            this.curReader = null;
        }
    }

    @Override
    public float getProgress() throws IOException, InterruptedException {
        long subprogress = 0L;
        if (null != this.curReader) {
            subprogress = (long) (this.curReader.getProgress() * this.hCatSplit.get(this.subIndex - 1).getLength());
        }
        // Indicate the total processed count.
        return Math.min(1.0F, (this.progress + subprogress) / (float) this.hCatSplit.getLength());
    }

    protected boolean initNextRecordReader() throws IOException {
        if (this.curReader != null) {
            // close current record reader if open
            this.curReader.close();
            this.curReader = null;
            if (this.subIndex > 0) {
                this.progress += this.hCatSplit.get(this.subIndex - 1).getLength();
            }
            LOG.debug("Closed current reader.  Current progress = " + progress);
        }

        if (this.subIndex == this.hCatSplit.length()) {
            LOG.debug("Done with all splits");
            return false;
        }

        try {
            // get a record reader for the subsplit-index chunk

            this.curReader = this.hCatExportFormat.createHCatRecordReader(this.hCatSplit.get(this.subIndex),
                    this.context);

            LOG.debug("Created a HCatRecordReader for split " + subIndex);
            // initialize() for the first RecordReader will be called by MapTask;
            // we're responsible for initializing subsequent RecordReaders.
            if (this.subIndex > 0) {
                this.curReader.initialize(this.hCatSplit.get(this.subIndex), this.context);
                LOG.info("Initialized reader with current split");
            }
        } catch (Exception e) {
            throw new IOException("Error initializing HCat record reader", e);
        }
        LOG.debug("Created record reader for subsplit " + subIndex);
        ++this.subIndex;
        return true;
    }
}