/**

  * Copyright 2005-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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.kuali.rice.krad.uif.container;

 import org.kuali.rice.krad.service.KRADServiceLocatorWeb;

 import org.kuali.rice.krad.uif.UifConstants;

 import org.kuali.rice.krad.uif.service.ExpressionEvaluatorService;

 import org.kuali.rice.krad.uif.util.ObjectPropertyUtils;

 import org.kuali.rice.krad.uif.view.View;

 import java.util.ArrayList;

 import java.util.HashMap;

 import java.util.List;

 import java.util.Map;

 /**

  * Collection filter that evaluates a configured el expression against each line

  *

  * @author Kuali Rice Team (rice.collab@kuali.org)

  */

 public class ELCollectionFilter implements CollectionFilter {

     private static final long serialVersionUID = 3273495753269940272L;

     private String expression = "";

     /**

      * Iterates through the collection and evaluates the el expression in context of the line. If the expression

      * evaluates to true, the line will remain, else be filtered out

      *

      * @see org.kuali.rice.krad.uif.container.CollectionFilter#filter(org.kuali.rice.krad.uif.view.View, Object,

      *      CollectionGroup)

      */

     @Override

     public List<Integer> filter(View view, Object model, CollectionGroup collectionGroup) {

         // get the collection for this group from the model

         List<Object> modelCollection = ObjectPropertyUtils.getPropertyValue(model,

                 collectionGroup.getBindingInfo().getBindingPath());

         // iterate through and add index that pass the expression

         List<Integer> showIndexes = new ArrayList<Integer>();

         int lineIndex = 0;

         for (Object line : modelCollection) {

             Map<String, Object> context = new HashMap<String, Object>(collectionGroup.getContext());

             context.put(UifConstants.ContextVariableNames.LINE, line);

             Boolean conditionPasses = (Boolean) getExpressionEvaluatorService().evaluateExpression(model, context,

                     expression);

             if (conditionPasses) {

                 showIndexes.add(lineIndex);

             }

             lineIndex++;

         }

         return showIndexes;

     }

     /**

      * Expression that will be evaluated for each line to determine whether the line should be filtered

      *

      * <p>

      * If expression passes, the line will remain in the collection, otherwise be filtered out. The expression given

      * should evaluate to a boolean

      * </p>

      *

      * @return String valid el expression that evaluates to a boolean.

      */

     public String getExpression() {

         return expression;

     }

     /**

      * Setter for the expression to use for filtering

      *

      * @param expression

      */

     public void setExpression(String expression) {

         this.expression = expression;

     }

     public ExpressionEvaluatorService getExpressionEvaluatorService() {

         return KRADServiceLocatorWeb.getExpressionEvaluatorService();

     }

 }