com.bigdata.rdf.sparql.ast.OrderByExpr Maven / Gradle / Ivy

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/**

Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016.  All rights reserved.

Contact:
     SYSTAP, LLC DBA Blazegraph
     2501 Calvert ST NW #106
     Washington, DC 20008
     [email protected]

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
package com.bigdata.rdf.sparql.ast;

import java.util.Map;

import com.bigdata.bop.BOp;
import com.bigdata.bop.IValueExpression;
import com.bigdata.rdf.internal.IV;

/**
 * An {@link IValueExpressionNode} paired with a flag to indicating an ascending
 * or descending sort order.
 * 
 * @author Bryan Thompson
 * @version $Id$
 */
public class OrderByExpr extends ASTBase implements
        IValueExpressionNodeContainer {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    interface Annotations extends ASTBase.Annotations {
        
        String ASCENDING = "ascending";

        boolean DEFAULT_ASCENDING = true;
        
    }
    
    /**
     * Constructor required for {@link com.bigdata.bop.BOpUtility#deepCopy(FilterNode)}.
     */
    public OrderByExpr(OrderByExpr op) {
        super(op);
    }

    /**
     * Required shallow copy constructor.
     */
    public OrderByExpr(BOp[] args, Map annotations) {
        super(args, annotations);
    }

    public OrderByExpr(final IValueExpressionNode ve, final boolean ascending) {

        super(new BOp[] { (BOp) ve }, null/* anns */);

        setAscending(ascending);

    }

    final public boolean isAscending() {

        return getProperty(Annotations.ASCENDING, Annotations.DEFAULT_ASCENDING);

    }

    final public void setAscending(boolean ascending) {

        setProperty(Annotations.ASCENDING, ascending);

    }
   
    public IValueExpressionNode getValueExpressionNode() {

        return (IValueExpressionNode) get(0);

    }

    public IValueExpression getValueExpression() {

        return getValueExpressionNode().getValueExpression();

    }

//    public String toString() {
//
//        final StringBuilder sb = new StringBuilder();
//
//        final boolean ascending = isAscending();
//        
//        if (!ascending) {
//
//            sb.append("desc(");
//            
//        }
//
//        sb.append(getValueExpressionNode().toString());
//
//        if (!ascending) {
//            
//            sb.append(")");
//            
//        }
//
//        return sb.toString();
//
//    }

}