/*
    * Copyright 2006-2007 the original author or authors.
    *
    * 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 org.springframework.batch.sample.domain.order.internal.valang;
  
  import java.util.List;
  
  import org.springframework.batch.sample.domain.order.LineItem;
  import org.springmodules.validation.valang.functions.AbstractFunction;
  import org.springmodules.validation.valang.functions.Function;
  
  
  /**
   * Validates total items count in Order.
   *
   * @author peter.zozom
   */
  public class TotalOrderItemsFunction extends AbstractFunction {
      public TotalOrderItemsFunction(Function[] arguments, int line, int column) {
          super(arguments, line, column);
          definedExactNumberOfArguments(2);
      }
  
      /**
       * @see org.springmodules.validation.valang.functions.AbstractFunction#doGetResult(java.lang.Object)
       */
      @SuppressWarnings("unchecked")
  	protected Object doGetResult(Object target) throws Exception {
          //get arguments
          int count = (Integer) getArguments()[0].getResult(target);
          Object value = getArguments()[1].getResult(target);
  
          Boolean result;
  
          //count items in list of order lines
          if (value instanceof List) {
              int totalItems = 0;
  
  			for (LineItem lineItem : ((List<LineItem>) value)) {
  				totalItems += lineItem.getQuantity();
  			}
  
  			result = (totalItems == count) ? Boolean.TRUE : Boolean.FALSE;
          } else {
              throw new Exception("No list for validation");
          }
  
          return result;
      }
  }