/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 at
 *
 * 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 org.apache.openjpa.persistence.query;

/**
 * Denotes an item of ORDER BY clause.
 *
 * @author Pinaki Poddar
 *
 */
public class OrderableItem extends AbstractVisitable
    implements OrderByItem, Visitable {
	
    private static final long serialVersionUID = 1L;
    private final Boolean _asc;
	private final ExpressionImpl _e;

	OrderableItem(ExpressionImpl path) {
		this(path, null);
	}

	public ExpressionImpl getExpression() {
		return _e;
	}

	OrderableItem(ExpressionImpl path, Boolean asc) {
		super();
		this._asc = asc;
		this._e = path;
	}

	@Override
    public String asExpression(AliasContext ctx) {
        return (ctx.hasAlias(_e) ? ctx.getAlias(_e) : _e.asExpression(ctx))
		    + (_asc == null ? "" : (_asc ? " ASC " : " DESC"));
	}
}
