/*
 * 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.executionengine.util;

import org.apache.pig.FuncSpec;
import org.apache.pig.PigException;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhysicalPlan;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POStore;
import org.apache.pig.builtin.BinStorage;
import org.apache.pig.impl.PigContext;
import org.apache.pig.impl.io.FileLocalizer;
import org.apache.pig.impl.io.FileSpec;
import org.apache.pig.impl.plan.NodeIdGenerator;
import org.apache.pig.impl.plan.OperatorKey;

/**
 * A collection of static methods for use by the executionengine
 * implementations.  A way to share common code.
 */
public class ExecTools {

    public static FileSpec checkLeafIsStore(
            PhysicalPlan plan,
            PigContext pigContext) throws ExecException {
        try {
            PhysicalOperator leaf = (PhysicalOperator)plan.getLeaves().get(0);
            FileSpec spec = null;
            if(!(leaf instanceof POStore)){
                String scope = leaf.getOperatorKey().getScope();
                POStore str = new POStore(new OperatorKey(scope,
                    NodeIdGenerator.getGenerator().getNextNodeId(scope)));
                spec = new FileSpec(FileLocalizer.getTemporaryPath(null,
                    pigContext).toString(),
                    new FuncSpec(BinStorage.class.getName()));
                str.setSFile(spec);
                plan.addAsLeaf(str);
            } else{
                spec = ((POStore)leaf).getSFile();
            }
            return spec;
        } catch (Exception e) {
            int errCode = 2045;
            String msg = "Internal error. Not able to check if the leaf node is a store operator.";
            throw new ExecException(msg, errCode, PigException.BUG, e);
        }
    }


}