vxquery-core/src/main/java/org/apache/vxquery/compiler/rewriter/rules/IntroduceIndexingRule.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.
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package org.apache.vxquery.compiler.rewriter.rules;

import org.apache.commons.lang3.mutable.Mutable;
import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException;
import org.apache.hyracks.algebricks.core.algebra.base.ILogicalOperator;
import org.apache.hyracks.algebricks.core.algebra.base.IOptimizationContext;
import org.apache.vxquery.common.VXQueryCommons;
import org.apache.vxquery.compiler.rewriter.VXQueryOptimizationContext;
import org.apache.vxquery.metadata.VXQueryIndexingDataSource;
import org.apache.vxquery.types.AnyItemType;
import org.apache.vxquery.types.Quantifier;
import org.apache.vxquery.types.SequenceType;

/**
 *
 */
public class IntroduceIndexingRule extends AbstractCollectionRule {

    @Override
    public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context) throws AlgebricksException {
        VXQueryOptimizationContext vxqueryContext = (VXQueryOptimizationContext) context;
        String args[] = getFunctionalArguments(opRef, VXQueryCommons.indexingFunctions);

        if (args != null) {

            String collection = args[0];
            String elementPath = args.length > 1?args[1]:null;

            // Build the new operator and update the query plan.
            int collectionId = vxqueryContext.newCollectionId();
            VXQueryIndexingDataSource ids = VXQueryIndexingDataSource.create(collectionId, collection, elementPath,
                    SequenceType.create(AnyItemType.INSTANCE, Quantifier.QUANT_STAR), functionCall.getFunctionIdentifier().getName());
            if (ids != null) {
                ids.setTotalDataSources(vxqueryContext.getTotalDataSources());

                // Known to be true because of collection name.
                return setDataSourceScan(ids, opRef);
            }
        }
        return false;
    }
}