asterix-om/src/main/java/edu/uci/ics/asterix/om/typecomputer/impl/NonTaggedUnaryMinusTypeComputer.java

package edu.uci.ics.asterix.om.typecomputer.impl;

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

import edu.uci.ics.asterix.om.typecomputer.base.IResultTypeComputer;
import edu.uci.ics.asterix.om.types.ATypeTag;
import edu.uci.ics.asterix.om.types.AUnionType;
import edu.uci.ics.asterix.om.types.BuiltinType;
import edu.uci.ics.asterix.om.types.IAType;
import edu.uci.ics.asterix.om.util.NonTaggedFormatUtil;
import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.AbstractFunctionCallExpression;
import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.IVariableTypeEnvironment;
import edu.uci.ics.hyracks.algebricks.core.algebra.metadata.IMetadataProvider;

public class NonTaggedUnaryMinusTypeComputer implements IResultTypeComputer {

    public static final NonTaggedUnaryMinusTypeComputer INSTANCE = new NonTaggedUnaryMinusTypeComputer();

    private NonTaggedUnaryMinusTypeComputer() {
    }

    @Override
    public IAType computeType(ILogicalExpression expression, IVariableTypeEnvironment env,
            IMetadataProvider<?, ?> metadataProvider) throws AlgebricksException {
        AbstractFunctionCallExpression fce = (AbstractFunctionCallExpression) expression;
        ILogicalExpression arg1 = fce.getArguments().get(0).getValue();
        if (((IAType) env.getType(arg1)).getTypeTag() == ATypeTag.UNION
                && NonTaggedFormatUtil.isOptionalField((AUnionType) env.getType(arg1)))
            return (IAType) env.getType(arg1);
        List<IAType> unionList = new ArrayList<IAType>();
        unionList.add(BuiltinType.ANULL);
        unionList.add((IAType) env.getType(arg1));
        return new AUnionType(unionList, "UnaryMinusResult");
    }

}