Order.java

/*
 * Copyright Aduna (http://www.aduna-software.com/) (c) 2007.
 *
 * Licensed under the Aduna BSD-style license.
 */
package org.openrdf.query.algebra;

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

/**
 * An order operator that can be used to order bindings as specified by a set of
 * value expressions.
 * 
 * @author Arjohn Kampman
 */
public class Order extends UnaryTupleOperator {

	/*-----------*
	 * Variables *
	 *-----------*/

	private List<OrderElem> elements = new ArrayList<OrderElem>();

	/*--------------*
	 * Constructors *
	 *--------------*/

	public Order() {
	}

	public Order(TupleExpr arg) {
		super(arg);
	}

	public Order(TupleExpr arg, OrderElem... elements) {
		this(arg);
		addElements(elements);
	}

	public Order(TupleExpr arg, Iterable<OrderElem> elements) {
		this(arg);
		addElements(elements);
	}

	/*---------*
	 * Methods *
	 *---------*/

	public List<OrderElem> getElements() {
		return elements;
	}

	public void setElements(List<OrderElem> elements) {
		this.elements = elements;
	}

	public void addElements(OrderElem... elements) {
		for (OrderElem pe : elements) {
			addElement(pe);
		}
	}

	public void addElements(Iterable<OrderElem> elements) {
		for (OrderElem pe : elements) {
			addElement(pe);
		}
	}

	public void addElement(OrderElem pe) {
		elements.add(pe);
		pe.setParentNode(this);
	}

	public <X extends Exception> void visit(QueryModelVisitor<X> visitor)
		throws X
	{
		visitor.meet(this);
	}

	@Override
	public <X extends Exception> void visitChildren(QueryModelVisitor<X> visitor)
		throws X
	{
		for (OrderElem elem : elements) {
			elem.visit(visitor);
		}

		super.visitChildren(visitor);
	}

	@Override
	public void replaceChildNode(QueryModelNode current, QueryModelNode replacement)
	{
		int index = elements.indexOf(current);
		if (index >= 0) {
			elements.set(index, (OrderElem)replacement);
			replacement.setParentNode(this);
		}
		else {
			super.replaceChildNode(current, replacement);
		}
	}

	@Override
	public Order clone() {
		Order clone = (Order)super.clone();

		List<OrderElem> elementsClone = new ArrayList<OrderElem>(getElements().size());
		for (OrderElem elem : getElements()) {
			elementsClone.add(elem.clone());
		}

		clone.setElements(elementsClone);

		return clone;
	}
}