Excerpt of the MetadataLookup EvalFunc.

gistfile1.java

package com.parsely.pig.cache;

import java.io.IOException;
import java.net.UnknownHostException;
import java.security.NoSuchAlgorithmException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Arrays;

import org.apache.commons.logging.Log;

import org.apache.pig.EvalFunc;
import org.apache.pig.PigWarning;
import org.apache.pig.data.DataType;
import org.apache.pig.data.Tuple;
import org.apache.pig.data.TupleFactory;
import org.apache.pig.impl.logicalLayer.schema.Schema;
import org.apache.pig.impl.logicalLayer.schema.Schema.FieldSchema;

import com.parsely.util.cache.Metadata;
import com.parsely.util.cache.ParselyMetadataService;

public class MetadataLookup extends EvalFunc<Tuple> {
    
    private ParselyMetadataService meta;
	private TupleFactory mTupleFactory = TupleFactory.getInstance();
	private DateFormat dateFormatter = new SimpleDateFormat("yyyy-MM-dd'T'HH:mmZ");
	private Log logger;
	
	public MetadataLookup(int lruSize) throws UnknownHostException {
		// This service opens up a connection to both mongo and redis
		this.meta = new ParselyMetadataService(lruSize);
		this.logger = getLogger();
	}
	
	public MetadataLookup() throws UnknownHostException {
		this(500);
	}
	

	@Override
	public Tuple exec(Tuple input) throws IOException {
	    // Returns a 5 element tuple by using calls to meta.fetch()
	    // which queries Redis/Mongo depending on the parameters
	}
	
	@Override
	public void finish() {
		// Closes the private mongo and redis connections within meta
		meta.close();
	}
	
}