org.apache.lens.lib.query.HadoopFileFormatter.java Source code

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Here is the source code for org.apache.lens.lib.query.HadoopFileFormatter.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.lens.lib.query;

import java.io.IOException;

import org.apache.lens.lib.query.LensFileOutputFormat.LensRowWriter;

import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.Reporter;

import com.google.common.base.Strings;

/**
 * A hadoop file formatter
 * <p></p>
 * This has capability to create output on Hadoop compatible files systems, with hadoop supported compression codecs.
 */
public class HadoopFileFormatter extends AbstractFileFormatter {

    /**
     * The output path.
     */
    private Path outputPath;

    /**
     * The row writer.
     */
    protected LensRowWriter rowWriter;

    /*
     * (non-Javadoc)
     *
     * @see org.apache.lens.lib.query.FileFormatter#setupOutputs()
     */
    public void setupOutputs() throws IOException {
        String pathStr = ctx.getResultSetParentDir();
        if (StringUtils.isBlank(pathStr)) {
            throw new IllegalArgumentException("No output path specified");
        }
        String outputPathStr = Strings.isNullOrEmpty(ctx.getQueryName()) ? ""
                : LensFileOutputFormat.getValidOutputFileName(ctx.getQueryName()) + "-";
        outputPath = new Path(pathStr, outputPathStr + ctx.getQueryHandle().toString());
        Path tmpWorkPath = new Path(pathStr, ctx.getQueryHandle().toString() + ".tmp");
        try {
            rowWriter = LensFileOutputFormat.createRecordWriter(ctx.getConf(), tmpWorkPath, Reporter.NULL,
                    ctx.getCompressOutput(), ctx.getOuptutFileExtn(), ctx.getResultEncoding());
            numRows = 0;
        } catch (IOException e) {
            throw new IllegalArgumentException("Could not create tmp path");
        }
    }

    /*
     * (non-Javadoc)
     *
     * @see org.apache.lens.lib.query.FileFormatter#writeHeader(java.lang.String)
     */
    public void writeHeader(String header) throws IOException {
        rowWriter.write(null, new Text(header));
    }

    /*
     * (non-Javadoc)
     *
     * @see org.apache.lens.lib.query.FileFormatter#writeFooter(java.lang.String)
     */
    public void writeFooter(String footer) throws IOException {
        rowWriter.write(null, new Text(footer));
    }

    /**
     * The cached row.
     */
    private Text cachedRow;

    /*
     * (non-Javadoc)
     *
     * @see org.apache.lens.lib.query.FileFormatter#writeRow(java.lang.String)
     */
    public void writeRow(String row) throws IOException {
        if (cachedRow == null) {
            cachedRow = new Text();
        }
        cachedRow.set(row);
        rowWriter.write(null, cachedRow);
        numRows++;
    }

    /*
     * (non-Javadoc)
     *
     * @see org.apache.lens.server.api.query.QueryOutputFormatter#commit()
     */
    @Override
    public void commit() throws IOException {
        rowWriter.close(Reporter.NULL);
        if (outputPath != null && rowWriter.getTmpPath() != null) {
            FileSystem fs = outputPath.getFileSystem(ctx.getConf());
            finalPath = outputPath;
            if (rowWriter.getExtn() != null) {
                finalPath = new Path(outputPath + rowWriter.getExtn());
            }
            finalPath = finalPath.makeQualified(fs);
            fs.rename(rowWriter.getTmpPath(), finalPath);
            ctx.setResultSetPath(finalPath.toString());
            fileSize = fs.getFileStatus(finalPath).getLen();
        }
    }

    /*
     * (non-Javadoc)
     *
     * @see org.apache.lens.server.api.query.QueryOutputFormatter#close()
     */
    @Override
    public void close() throws IOException {
        if (null != rowWriter) {
            rowWriter.close(Reporter.NULL);
        }
    }

    @Override
    public Path getTmpPath() {
        return rowWriter.getTmpPath();
    }

    @Override
    public String getEncoding() {
        return rowWriter.getEncoding();
    }
}