basicroutingpolicy.java

High performance DB query

/*
 * @(#)$Id: BasicRoutingPolicy.java,v 1.6 2004/07/02 23:59:21 huebsch Exp $
 *
 * Copyright (c) 2001-2004 Regents of the University of California.
 * All rights reserved.
 *
 * This file is distributed under the terms in the attached BERKELEY-LICENSE
 * file. If you do not find these files, copies can be found by writing to:
 * Computer Science Division, Database Group, Universite of California,
 * 617 Soda Hall #1776, Berkeley, CA 94720-1776. Attention: Berkeley License
 *
 * Copyright (c) 2003-2004 Intel Corporation. All rights reserved.
 *
 * This file is distributed under the terms in the attached INTEL-LICENSE file.
 * If you do not find these files, copies can be found by writing to:
 * Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300,
 * Berkeley, CA, 94704.  Attention:  Intel License Inquiry.
 */


package pier.helpers.routingpolicy;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import org.apache.log4j.Logger;
import pier.data.Tuple;
import pier.operators.Eddy;
import services.Output;
import util.BitID;
import util.logging.LogMessage;

/**
 * Class BasicRoutingPolicy
 *
 * This class is a simple, "first" operator routing policy
 * Builds a special nextOp map thats used to quickly determine where to send the tuple
 */
public class BasicRoutingPolicy extends RoutingPolicy {

    private static Logger logger = Logger.getLogger(BasicRoutingPolicy.class);

    /*
     * map of done bits -> next operator list.  The first operator in the
     *  list for a given signature will be the operator chosen
     *  Note that there is another way to do this - can also have 'next ready'
     *  stored and then compute the next op from that.  TBD how I will actually
     *  do this.
     */
    protected HashMap nextOperatorMap;

    /**
     * Constructor BasicRoutingPolicy
     *
     *
     * @param sourceInitMap
     * @param doneReadyMap
     */
    public BasicRoutingPolicy(HashMap sourceInitMap, HashMap doneReadyMap) {
        super(sourceInitMap, doneReadyMap);

        // build the next operator map based on the two maps
        nextOperatorMap = buildOperatorMap(sourceInitMap, doneReadyMap);

        if (Output.debuggingEnabled) {
            logger.debug(new LogMessage(new Object[]{"nextOperatorMap: ",
                                                     nextOperatorMap}));
        }
    }

    /**
     * Method buildOperatorMap
     * We build this map on eddy initialization so we dont have to mess with bit operations at
     * runtime.
     *
     * @param sourceInitMap
     * @param doneReadyMap
     * @return
     */
    protected HashMap buildOperatorMap(HashMap sourceInitMap,
                                       HashMap doneReadyMap) {
        HashMap nextOperatorMap = new HashMap();

        // first get the ready bits from the source init map
        // get an iterator to the ready bits
        Iterator sourceIterator = sourceInitMap.values().iterator();

        // iterate by key (done bits)
        while (sourceIterator.hasNext()) {

            // pull out the ready bits
            BitID readyBits = (BitID) (sourceIterator.next());

            // the array of possible operators
            ArrayList possibleOperators =
                new ArrayList(readyBits.cardinality());

            // find the bits that are on and thier corresponding position.  Fill in the operator array
            int searchIndex = 0;
            int operatorIndex = readyBits.nextSetBit(searchIndex);

            while (operatorIndex != -1) {

                // add this position to the arraylist
                possibleOperators.add(new Integer(operatorIndex));

                searchIndex = operatorIndex + 1;
                operatorIndex = readyBits.nextSetBit(searchIndex);
            }

            nextOperatorMap.put(readyBits, possibleOperators);
        }

        // now make operators from the doneready map
        Iterator readyIterator = doneReadyMap.values().iterator();

        while (readyIterator.hasNext()) {
            BitID readyBits = (BitID) (readyIterator.next());
            ArrayList possibleOperators =
                new ArrayList(readyBits.cardinality());

            // find the bits that are on and thier corresponding position.  Fill in the operator array
            int searchIndex = 0;
            int operatorIndex = readyBits.nextSetBit(searchIndex);

            while (operatorIndex != -1) {

                // add this position to the arraylist
                possibleOperators.add(new Integer(operatorIndex));

                searchIndex = operatorIndex + 1;
                operatorIndex = readyBits.nextSetBit(searchIndex);
            }

            nextOperatorMap.put(readyBits, possibleOperators);
        }

        return nextOperatorMap;
    }

    /**
     * Method getNextOperator
     *
     *
     * Based on the metadata in the tuple (ready, done bits), find
     * the next operator to route to according to the routing policy
     * Basic just pulls the first operator off the possible list
     *
     * @param item the tuple to determine the next op for
     * @return
     */
    public int getNextOperator(Tuple item) {
        if (Output.debuggingEnabled) {
            logger.debug(new LogMessage(new Object[]{"Readybits: ",
                                                     (BitID) item.getMetadata(
                                                         Eddy.READY_BITS)}));
        }

        // simply look up the next operator in the next op table and return it
        ArrayList possibleOps = (ArrayList) nextOperatorMap.get(
                                    (BitID) item.getMetadata(Eddy.READY_BITS));

        if ((possibleOps == null) || (possibleOps.size() < 1)) {
            if (Output.debuggingEnabled) {
                logger.debug(new LogMessage(new Object[]{
                    "Error finding next op!", }));

                return -1;
            }
        }

        // grab the first operator
        Integer nextOp = (Integer) possibleOps.get(0);

        // would re-optimize routing strategy here (if we decided to do such a wacky thing), or could be done batched
        if (Output.debuggingEnabled) {
            logger.debug(new LogMessage(new Object[]{"Next op: ",
                                                     nextOp.intValue() + ""}));
        }

        return nextOp.intValue();
    }
}