src/org/apache/pig/backend/hadoop/executionengine/physicalLayer/relationalOperators/POPreCombinerLocalRearrange.java

/*
 * 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.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators;

import java.util.ArrayList;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.POStatus;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.Result;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.ExpressionOperator;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhyPlanVisitor;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhysicalPlan;
import org.apache.pig.data.DataBag;
import org.apache.pig.data.DataType;
import org.apache.pig.data.SingleTupleBag;
import org.apache.pig.data.Tuple;
import org.apache.pig.impl.plan.OperatorKey;
import org.apache.pig.impl.plan.VisitorException;

/**
 * A specialized local rearrange operator which behaves
 * like the regular local rearrange in the getNext()
 * as far as getting its input and constructing the
 * "key" out of the input. It then returns a tuple with
 * two fields - the key in the first position and the
 * "value" inside a bag in the second position. This output
 * format resembles the format out of a Package. This output
 * will feed to a foreach which expects this format.
 */
public class POPreCombinerLocalRearrange extends PhysicalOperator {
    private static final Log log = LogFactory.getLog(POPreCombinerLocalRearrange.class);

    protected static final long serialVersionUID = 1L;

    private static final Result ERR_RESULT = new Result();

    protected List<PhysicalPlan> plans;

    protected List<ExpressionOperator> leafOps;

    protected byte keyType;

    public POPreCombinerLocalRearrange(OperatorKey k) {
        this(k, -1, null);
    }

    public POPreCombinerLocalRearrange(OperatorKey k, int rp) {
        this(k, rp, null);
    }

    public POPreCombinerLocalRearrange(OperatorKey k, List<PhysicalOperator> inp) {
        this(k, -1, inp);
    }

    public POPreCombinerLocalRearrange(OperatorKey k, int rp, List<PhysicalOperator> inp) {
        super(k, rp, inp);
        leafOps = new ArrayList<ExpressionOperator>();
    }

    @Override
    public void visit(PhyPlanVisitor v) throws VisitorException {
        v.visitPreCombinerLocalRearrange(this);
    }

    @Override
    public String name() {
        return getAliasString() + "Pre Combiner Local Rearrange" + "["
                + DataType.findTypeName(resultType) + "]" + "{"
                + DataType.findTypeName(keyType) + "} - " + mKey.toString();
    }

    @Override
    public boolean supportsMultipleInputs() {
        return false;
    }

    @Override
    public boolean supportsMultipleOutputs() {
        return false;
    }

    /**
     * Overridden since the attachment of the new input should cause the old
     * processing to end.
     */
    @Override
    public void attachInput(Tuple t) {
        super.attachInput(t);
    }

    /**
     * Calls getNext on the generate operator inside the nested
     * physical plan. Converts the generated tuple into the proper
     * format, i.e, (key,indexedTuple(value))
     */
    @Override
    public Result getNextTuple() throws ExecException {

        Result inp = null;
        Result res = ERR_RESULT;
        while (true) {
            inp = processInput();
            if (inp.returnStatus == POStatus.STATUS_EOP || inp.returnStatus == POStatus.STATUS_ERR) {
                break;
            }
            if (inp.returnStatus == POStatus.STATUS_NULL) {
                continue;
            }

            for (PhysicalPlan ep : plans) {
                ep.attachInput((Tuple)inp.result);
            }
            List<Result> resLst = new ArrayList<Result>();
            for (ExpressionOperator op : leafOps){

                switch(op.getResultType()){
                case DataType.BAG:
                case DataType.BOOLEAN:
                case DataType.BYTEARRAY:
                case DataType.CHARARRAY:
                case DataType.DOUBLE:
                case DataType.FLOAT:
                case DataType.INTEGER:
                case DataType.LONG:
                case DataType.BIGINTEGER:
                case DataType.BIGDECIMAL:
                case DataType.DATETIME:
                case DataType.MAP:
                case DataType.TUPLE:
                    res = op.getNext(op.getResultType());
                    break;
                default:
                    log.error("Invalid result type: "
                            + DataType.findType(op.getResultType()));
                    break;
                }

                if (res.returnStatus != POStatus.STATUS_OK) {
                    return res;
                }

                resLst.add(res);
            }
            res.result = constructLROutput(resLst,(Tuple)inp.result);
            res.returnStatus = POStatus.STATUS_OK;

            return res;
        }
        return inp;
    }

    protected Tuple constructLROutput(List<Result> resLst, Tuple value) throws ExecException{
        //Construct key
        Object key;
        if(resLst.size()>1){
            Tuple t = mTupleFactory.newTuple(resLst.size());
            int i=-1;
            for(Result res : resLst) {
                t.set(++i, res.result);
            }
            key = t;
        }
        else{
            key = resLst.get(0).result;
        }

        Tuple output = mTupleFactory.newTuple(2);
        output.set(0, key);
        // put the value in a bag so that the initial
        // version of the Algebraics will get a bag as
        // they would expect.
        DataBag bg = new SingleTupleBag(value);
        output.set(1, bg);
        return output;
    }

    public byte getKeyType() {
        return keyType;
    }

    public void setKeyType(byte keyType) {
        this.keyType = keyType;
    }

    public List<PhysicalPlan> getPlans() {
        return plans;
    }

    public void setPlans(List<PhysicalPlan> plans) {
        this.plans = plans;
        leafOps.clear();
        for (PhysicalPlan plan : plans) {
            ExpressionOperator leaf = (ExpressionOperator)plan.getLeaves().get(0);
            leafOps.add(leaf);
        }
    }

    @Override
    public Tuple illustratorMarkup(Object in, Object out, int eqClassIndex) {
        return null;
    }

    @Override
    public POPreCombinerLocalRearrange clone() throws CloneNotSupportedException {
        POPreCombinerLocalRearrange clone = (POPreCombinerLocalRearrange) super.clone();
        clone.leafOps = new ArrayList<ExpressionOperator>();
        clone.setPlans(clonePlans(plans));
        return clone;
    }
}