/*******************************************************************************
 * Copyright 2013 SAP AG
 * 
 * Licensed 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 com.sap.core.odata.api.uri.expression;

import java.util.List;

/**
 * Represents a $orderby expression in the expression tree returned by
 * {@link com.sap.core.odata.api.uri.UriParser#parseOrderByString(com.sap.core.odata.api.edm.EdmEntityType, String) }
 * Used to define the <b>root</b> expression node in an $filter expression tree.
 * 
 * @author SAP AG
 */
public interface OrderByExpression extends CommonExpression {
  /**
   * @return Returns the $filter expression string used to build the expression tree
   */
  String getExpressionString();

  /**
   * @return 
   *   Returns a ordered list of order expressions contained in the $orderby expression string
   *   <p>
   *   <b>For example</b>: The orderby expression build from "$orderby=name asc, age desc" 
   *   would contain to order expression.  
   */
  public List<OrderExpression> getOrders();

  /**
   * @return Returns the count of order expressions contained in the $orderby expression string
   */
  public int getOrdersCount();

}