Mapper for processing ZipFile entries

gistfile1.java

/**
* This Mapper class checks the filename ends with the .txt extension, cleans
* the text and then applies the simple WordCount algorithm.
*/
public static class MyMapper
	extends Mapper<Text, BytesWritable, Text, IntWritable>
{
	private final static IntWritable one = new IntWritable( 1 );
	private Text word = new Text();

	public void map( Text key, BytesWritable value, Context context )
	    throws IOException, InterruptedException
	{
	    // NOTE: the filename is the *full* path within the ZIP file
	    // e.g. "subdir1/subsubdir2/Ulysses-18.txt"
	    String filename = key.toString();
	    LOG.info( "map: " + filename );
	    
	    // We only want to process .txt files
	    if ( filename.endsWith(".txt") == false )
		return;
	    
	    // Prepare the content 
	    String content = new String( value.getBytes(), "UTF-8" );
	    content = content.replaceAll( "[^A-Za-z \n]", "" ).toLowerCase();
	    
	    // Tokenize the content
	    StringTokenizer tokenizer = new StringTokenizer( content );
	    while ( tokenizer.hasMoreTokens() )
	    {
		word.set( tokenizer.nextToken() );
		context.write( word, one );
	    }
	}
}