io.github.vmzakharov.ecdataframe.dsl.ProjectionExpr Maven / Gradle / Ivy

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A tabular data structure based on the Eclipse Collections framework

There is a newer version: 1.2.0

package io.github.vmzakharov.ecdataframe.dsl;

import io.github.vmzakharov.ecdataframe.dsl.value.Value;
import io.github.vmzakharov.ecdataframe.dsl.visitor.ExpressionEvaluationVisitor;
import io.github.vmzakharov.ecdataframe.dsl.visitor.ExpressionVisitor;
import io.github.vmzakharov.ecdataframe.dsl.visitor.PrettyPrintVisitor;
import org.eclipse.collections.api.list.ListIterable;
import org.eclipse.collections.api.list.MutableList;
import org.eclipse.collections.impl.factory.Lists;

public class ProjectionExpr
implements Expression
{
    private final Expression whereClause;
    private final ListIterable projectionElements;
    private final MutableList elementNames = Lists.mutable.of();
    private final MutableList projectionExpressions = Lists.mutable.of();

    public ProjectionExpr(ListIterable newProjectionElements)
    {
        this(newProjectionElements, null);
    }

    public ProjectionExpr(ListIterable newProjectionElements, Expression newWhereClause)
    {
        this.projectionElements = newProjectionElements;
        this.whereClause = newWhereClause;

        for (int i = 0; i < this.projectionElements.size(); i++)
        {
            Expression element = this.projectionElements.get(i);
            if (element instanceof AliasExpr)
            {
                this.elementNames.add(((AliasExpr) element).getAlias());
                this.projectionExpressions.add(((AliasExpr) element).getExpression());
            }
            else
            {
                this.elementNames.add(PrettyPrintVisitor.exprToString(element));
                this.projectionExpressions.add(element);
            }
        }
    }

    @Override
    public Value evaluate(ExpressionEvaluationVisitor visitor)
    {
        return visitor.visitProjectionExpr(this);
    }

    @Override
    public void accept(ExpressionVisitor visitor)
    {
        visitor.visitProjectionExpr(this);
    }

    public Expression getWhereClause()
    {
        return this.whereClause;
    }

    public ListIterable getProjectionElements()
    {
        return this.projectionElements;
    }

    public ListIterable getProjectionExpressions()
    {
        return this.projectionExpressions;
    }

    public ListIterable getElementNames()
    {
        return this.elementNames;
    }
}