Example usage for org.apache.hadoop.mapreduce.lib.db DBInputFormat setInput

Introduction

In this page you can find the example usage for org.apache.hadoop.mapreduce.lib.db DBInputFormat setInput.

Prototype

public static void setInput(Job job, Class<? extends DBWritable> inputClass, String inputQuery,
        String inputCountQuery) 

Source Link

Document

Initializes the map-part of the job with the appropriate input settings.

Usage

From source file:link.neolink.datamonster.Datamonster.java

License:Apache License

/**
 * Mapper configuration, with a dataset from SQL
 *
 * @param query/*w w w. j  ava2 s .  c o  m*/
 *    The SQL Query
 * @param mapper
 *    The mapper class
 */
public void mapperConfiguration(String query, Class<? extends Mapper> mapper) {
    if (this.inType != Type.MAGIC) {
        System.err.println("Input type already defined.");
        System.exit(-1);
    }

    if (this.dataWritable == null) {
        System.err.println("No DataWritable(s) found, you need to call setDataWritable() before!.");
        System.exit(-1);
    }

    this.inType = Type.SELECT;
    this.job.setMapperClass(mapper);
    this.job.setMapOutputKeyClass(Text.class);
    this.job.setMapOutputValueClass(this.dataWritable);
    this.job.setInputFormatClass(DBInputFormat.class);

    if (this.inputWritable != null) {
        DBInputFormat.setInput(this.job, this.inputWritable, query,
                "SELECT COUNT(*) FROM (" + query + ") AS query_count");
    } else if (this.ioWritable != null) {
        DBInputFormat.setInput(this.job, this.ioWritable, query,
                "SELECT COUNT(*) FROM (" + query + ") AS query_count");
    } else {
        System.err.println("Input is SQL, but no input Writable class defined");
        System.exit(-1);
    }
}

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