hyracks-algebricks/hyracks-algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/operators/logical/UnnestMapOperator.java

/*
 * Copyright 2009-2010 by The Regents of the University of California
 * Licensed 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 from
 * 
 *     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 edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical;

import java.util.List;

import org.apache.commons.lang3.mutable.Mutable;

import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalOperatorTag;
import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.IVariableTypeEnvironment;
import edu.uci.ics.hyracks.algebricks.core.algebra.properties.VariablePropagationPolicy;
import edu.uci.ics.hyracks.algebricks.core.algebra.typing.ITypingContext;
import edu.uci.ics.hyracks.algebricks.core.algebra.typing.NonPropagatingTypeEnvironment;
import edu.uci.ics.hyracks.algebricks.core.algebra.visitors.ILogicalOperatorVisitor;
import edu.uci.ics.hyracks.algebricks.core.api.exceptions.AlgebricksException;

/**
 * This operator may go away after we add indexes to Algebricks.
 * 
 */
public class UnnestMapOperator extends AbstractUnnestOperator {

    private final List<Object> variableTypes; // TODO: get rid of this and

    // deprecate UnnestMap

    public UnnestMapOperator(List<LogicalVariable> variables, Mutable<ILogicalExpression> expression,
            List<Object> variableTypes) {
        super(variables, expression);
        this.variableTypes = variableTypes;
    }

    @Override
    public LogicalOperatorTag getOperatorTag() {
        return LogicalOperatorTag.UNNEST_MAP;
    }

    @Override
    public <R, T> R accept(ILogicalOperatorVisitor<R, T> visitor, T arg) throws AlgebricksException {
        return visitor.visitUnnestMapOperator(this, arg);
    }

    /**
     * 
     * UnnestMap doesn't propagate input variables, because currently it is only
     * used to search indexes. In the future, it would be nice to have the
     * choice to propagate input variables or not.
     * 
     */
    @Override
    public VariablePropagationPolicy getVariablePropagationPolicy() {
        return new VariablePropagationPolicy() {

            @Override
            public void propagateVariables(IOperatorSchema target, IOperatorSchema... sources)
                    throws AlgebricksException {
                for (LogicalVariable v : variables) {
                    target.addVariable(v);
                }
            }
        };
    }

    public List<Object> getVariableTypes() {
        return variableTypes;
    }

    @Override
    public IVariableTypeEnvironment computeOutputTypeEnvironment(ITypingContext ctx) throws AlgebricksException {
        IVariableTypeEnvironment env = new NonPropagatingTypeEnvironment(ctx.getExpressionTypeComputer(),
                ctx.getMetadataProvider());
        int n = variables.size();
        for (int i = 0; i < n; i++) {
            env.setVarType(variables.get(i), variableTypes.get(i));
        }
        return env;
    }

}