/*

  * Copyright 2007 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.kns.web.struts.action;

 import java.io.IOException;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.Collections;

 import java.util.HashMap;

 import java.util.List;

 import java.util.Map;

 import java.util.Properties;

 import java.util.Set;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import org.apache.commons.beanutils.BeanComparator;

 import org.apache.commons.lang.StringUtils;

 import org.apache.struts.action.ActionForm;

 import org.apache.struts.action.ActionForward;

 import org.apache.struts.action.ActionMapping;

 import org.kuali.rice.core.util.RiceConstants;

 import org.kuali.rice.kns.lookup.CollectionIncomplete;

 import org.kuali.rice.kns.lookup.LookupResultsService;

 import org.kuali.rice.kns.lookup.LookupUtils;

 import org.kuali.rice.kns.lookup.Lookupable;

 import org.kuali.rice.kns.lookup.HtmlData.InputHtmlData;

 import org.kuali.rice.kns.service.KNSServiceLocator;

 import org.kuali.rice.kns.service.SequenceAccessorService;

 import org.kuali.rice.kns.util.GlobalVariables;

 import org.kuali.rice.kns.util.KNSConstants;

 import org.kuali.rice.kns.util.UrlFactory;

 import org.kuali.rice.kns.web.struts.form.MultipleValueLookupForm;

 import org.kuali.rice.kns.web.ui.Column;

 import org.kuali.rice.kns.web.ui.ResultRow;

 /**

  * This class serves as the struts action for implementing multiple value lookups

  */

 public class KualiMultipleValueLookupAction extends KualiLookupAction implements KualiTableRenderAction {

     private static final org.apache.log4j.Logger LOG = org.apache.log4j.Logger.getLogger(KualiMultipleValueLookupAction.class);

     /**

      * If there is no app param defined for the # rows/page, then this value

      * will be used for the default

      * 

      * @see KualiMultipleValueLookupAction#getMaxRowsPerPage(MultipleValueLookupForm)

      */

     public static final int DEFAULT_MAX_ROWS_PER_PAGE = 50;

     /**

      * This method performs the search, and will be responsible for persisting the results via the LookupResultsService.

      * This overrides the superclass's search action method b/c of the differences in how the results are generated and it populates

      * certain attributes that are specific to MultipleValueLookupForm

      * 

      * @param mapping

      * @param form must be an instance of MultipleValueLookupForm

      * @param request

      * @param response 

      */

     @Override

     public ActionForward search(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {

         MultipleValueLookupForm multipleValueLookupForm = (MultipleValueLookupForm) form;

         // If this is a new search, clear out the old search results.

             String methodToCall = findMethodToCall(form, request);

                 if (methodToCall.equalsIgnoreCase("search")) {

                         GlobalVariables.getUserSession().removeObjectsByPrefix(KNSConstants.SEARCH_METHOD);

                 }

         Lookupable kualiLookupable = multipleValueLookupForm.getLookupable();

         if (kualiLookupable == null) {

             LOG.error("Lookupable is null.");

             throw new RuntimeException("Lookupable is null.");

         }

         Collection displayList = new ArrayList();

         List<ResultRow> resultTable = new ArrayList<ResultRow>();

         // validate search parameters

         kualiLookupable.validateSearchParameters(multipleValueLookupForm.getFields());

         boolean bounded = true;

         displayList = performMultipleValueLookup(multipleValueLookupForm, resultTable, getMaxRowsPerPage(multipleValueLookupForm), bounded);

         if (kualiLookupable.isSearchUsingOnlyPrimaryKeyValues()) {

             multipleValueLookupForm.setSearchUsingOnlyPrimaryKeyValues(true);

             multipleValueLookupForm.setPrimaryKeyFieldLabels(kualiLookupable.getPrimaryKeyFieldLabels());

         }

         else {

             multipleValueLookupForm.setSearchUsingOnlyPrimaryKeyValues(false);

             multipleValueLookupForm.setPrimaryKeyFieldLabels(KNSConstants.EMPTY_STRING);

         }

         //request.setAttribute("reqSearchResultsActualSize", ((CollectionIncomplete) displayList).getActualSizeIfTruncated());

         if ( displayList instanceof CollectionIncomplete ){

             request.setAttribute("reqSearchResultsActualSize", ((CollectionIncomplete) displayList).getActualSizeIfTruncated());

         } else {

             request.setAttribute("reqSearchResultsActualSize", displayList.size() );

         }

         request.setAttribute("reqSearchResults", resultTable);

         //multipleValueLookupForm.setResultsActualSize((int) ((CollectionIncomplete) displayList).getActualSizeIfTruncated().longValue());

         if ( displayList instanceof CollectionIncomplete ){

                 multipleValueLookupForm.setResultsActualSize((int) ((CollectionIncomplete) displayList).getActualSizeIfTruncated().longValue());    

         } else {

                 multipleValueLookupForm.setResultsActualSize(displayList.size()); 

         }

         multipleValueLookupForm.setResultsLimitedSize(resultTable.size());

         if (request.getParameter(KNSConstants.SEARCH_LIST_REQUEST_KEY) != null) {

             GlobalVariables.getUserSession().removeObject(request.getParameter(KNSConstants.SEARCH_LIST_REQUEST_KEY));

         }

         request.setAttribute(KNSConstants.SEARCH_LIST_REQUEST_KEY, GlobalVariables.getUserSession().addObject(resultTable, KNSConstants.SEARCH_LIST_KEY_PREFIX));

         String refreshCaller = request.getParameter(KNSConstants.REFRESH_CALLER);

         return mapping.findForward(RiceConstants.MAPPING_BASIC);

     }

     /**

      * This method switches to another page on a multi-value lookup

      * 

      * @param mapping

      * @param form must be an instance of MultipleValueLookupForm

      * @param request

      * @param response

      * @return

      * @throws Exception

      */

     public ActionForward switchToPage(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {

         MultipleValueLookupForm multipleValueLookupForm = (MultipleValueLookupForm) form;

         List<ResultRow> resultTable = switchToPage(multipleValueLookupForm, getMaxRowsPerPage(multipleValueLookupForm));

         request.setAttribute("reqSearchResults", resultTable);

         return mapping.findForward(RiceConstants.MAPPING_BASIC);

     }

     /**

      * This method sorts a column.  If the page is currently sorted on a certain column,

      * and the same column is selected to be sorted again, then the results will be 

      * reversed.  After the search method is called, it is difficult to determine the sort

      * order of the result table, so no column is considered sorted.  So, after a search, we were

      * to click sort on an already sorted column, it would appear to have no effect.  Subsequent clicks

      * would tell you  

      * 

      * @param mapping

      * @param form must be an instance of MultipleValueLookupForm

      * @param request

      * @param response

      * @return

      * @throws Exception

      */

     public ActionForward sort(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {

         MultipleValueLookupForm multipleValueLookupForm = (MultipleValueLookupForm) form;

         List<ResultRow> resultTable = sort(multipleValueLookupForm, getMaxRowsPerPage(multipleValueLookupForm));

         request.setAttribute("reqSearchResults", resultTable);

         return mapping.findForward(RiceConstants.MAPPING_BASIC);

     }

     /**

      * This method does the processing necessary to return selected results and sends a redirect back to the lookup caller

      * 

      * @param mapping

      * @param form must be an instance of MultipleValueLookupForm

      * @param request

      * @param response

      * @return

      * @throws Exception

      */

     public ActionForward prepareToReturnSelectedResults(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {

         MultipleValueLookupForm multipleValueLookupForm = (MultipleValueLookupForm) form;

         if (StringUtils.isBlank(multipleValueLookupForm.getLookupResultsSequenceNumber())) {

             // no search was executed

             return prepareToReturnNone(mapping, form, request, response);

         }

         prepareToReturnSelectedResultBOs(multipleValueLookupForm);

         // build the parameters for the refresh url

         Properties parameters = new Properties();

         parameters.put(KNSConstants.LOOKUP_RESULTS_BO_CLASS_NAME, multipleValueLookupForm.getBusinessObjectClassName());

         parameters.put(KNSConstants.LOOKUP_RESULTS_SEQUENCE_NUMBER, multipleValueLookupForm.getLookupResultsSequenceNumber());

         parameters.put(KNSConstants.DOC_FORM_KEY, multipleValueLookupForm.getFormKey());

         parameters.put(KNSConstants.DISPATCH_REQUEST_PARAMETER, KNSConstants.RETURN_METHOD_TO_CALL);

         parameters.put(KNSConstants.REFRESH_CALLER, KNSConstants.MULTIPLE_VALUE);

         parameters.put(KNSConstants.ANCHOR, multipleValueLookupForm.getLookupAnchor());

         parameters.put(KNSConstants.LOOKED_UP_COLLECTION_NAME, multipleValueLookupForm.getLookedUpCollectionName());

         if(multipleValueLookupForm.getDocNum() != null){

                 parameters.put(KNSConstants.DOC_NUM, multipleValueLookupForm.getDocNum());

         }

         String backUrl = UrlFactory.parameterizeUrl(multipleValueLookupForm.getBackLocation(), parameters);

         return new ActionForward(backUrl, true);

     }

     /**

      * This method selects all results across all pages

      * @param mapping

      * @param form must be an instance of MultipleValueLookupForm

      * @param request

      * @param response

      * @return

      * @throws Exception

      */

     public ActionForward selectAll(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {

         MultipleValueLookupForm multipleValueLookupForm = (MultipleValueLookupForm) form;

         List<ResultRow> resultTable = selectAll(multipleValueLookupForm, getMaxRowsPerPage(multipleValueLookupForm));

         request.setAttribute("reqSearchResults", resultTable);

         return mapping.findForward(RiceConstants.MAPPING_BASIC);

     }

     /**

      * This method unselects all results across all pages

      * 

      * @param mapping

      * @param form must be an instance of MultipleValueLookupForm

      * @param request

      * @param response

      * @return

      * @throws Exception

      */

     public ActionForward unselectAll(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {

         MultipleValueLookupForm multipleValueLookupForm = (MultipleValueLookupForm) form;

         List<ResultRow> resultTable = unselectAll(multipleValueLookupForm, getMaxRowsPerPage(multipleValueLookupForm));

         request.setAttribute("reqSearchResults", resultTable);

         return mapping.findForward(RiceConstants.MAPPING_BASIC);

     }

     /**

      * This method overrides the super class cancel method because it is basically equivalent to clicking prepare to return none 

      * 

      * @see org.kuali.rice.kns.web.struts.action.KualiLookupAction#cancel(org.apache.struts.action.ActionMapping, org.apache.struts.action.ActionForm, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)

      */

     @Override

     public ActionForward cancel(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {

         return prepareToReturnNone(mapping, form, request, response);

     }

     /**

      * This method returns none of the selected results and redirects back to the lookup caller.

      * @param mapping

      * @param form must be an instance of MultipleValueLookupForm

      * @param request

      * @param response

      * @return

      * @throws Exception

      */

     public ActionForward prepareToReturnNone(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {

         MultipleValueLookupForm multipleValueLookupForm = (MultipleValueLookupForm) form;

         prepareToReturnNone(multipleValueLookupForm);

         // build the parameters for the refresh url

         Properties parameters = new Properties();

         parameters.put(KNSConstants.DOC_FORM_KEY, multipleValueLookupForm.getFormKey());

         parameters.put(KNSConstants.DISPATCH_REQUEST_PARAMETER, KNSConstants.RETURN_METHOD_TO_CALL);

         parameters.put(KNSConstants.REFRESH_CALLER, KNSConstants.MULTIPLE_VALUE);

         parameters.put(KNSConstants.ANCHOR, multipleValueLookupForm.getLookupAnchor());

         if(multipleValueLookupForm.getDocNum() != null){

                 parameters.put(KNSConstants.DOC_NUM, multipleValueLookupForm.getDocNum());

         }

         String backUrl = UrlFactory.parameterizeUrl(multipleValueLookupForm.getBackLocation(), parameters);

         return new ActionForward(backUrl, true);

     }

     /**

      * This method prepares to export results.  Note: this method will not look for any rows selected since the last page view, so it is best

      * that exporting opens in a new browser window.

      * 

      * @param mapping

      * @param form must be an instance of MultipleValueLookupForm

      * @param request

      * @param response

      * @return

      * @throws Exception

      */

     public ActionForward export(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {

         MultipleValueLookupForm multipleValueLookupForm = (MultipleValueLookupForm) form;

         List<ResultRow> resultTable = prepareToExport(multipleValueLookupForm);

         request.setAttribute("reqSearchResults", resultTable);

         return mapping.findForward(RiceConstants.MAPPING_BASIC);

     }

     /**

      * This method performs the lookup and returns a collection of lookup items.  Also initializes values in the form

      * that will allow the multiple value lookup page to render

      * 

      * @param multipleValueLookupForm

      * @param resultTable a list of result rows (used to generate what's shown in the UI).  This list will be modified by this method

      * @param maxRowsPerPage

      * @param bounded whether the results will be bounded

      * @return the list of result BOs, possibly bounded by size

      */

     protected Collection performMultipleValueLookup(MultipleValueLookupForm multipleValueLookupForm, List<ResultRow> resultTable, int maxRowsPerPage, boolean bounded) {

         Lookupable lookupable = multipleValueLookupForm.getLookupable();

         Collection displayList = lookupable.performLookup(multipleValueLookupForm, resultTable, bounded);

         List defaultSortColumns = lookupable.getDefaultSortColumns();

         if (defaultSortColumns != null && !defaultSortColumns.isEmpty() && resultTable != null && !resultTable.isEmpty()) {

             // there's a default sort order, just find the first sort column, and we can't go wrong

             String firstSortColumn = (String) defaultSortColumns.get(0);

             // go thru the first result row to find the index of the column (more efficient than calling lookupable.getColumns since we don't have to recreate column list)

             int firstSortColumnIdx = -1;

             List<Column> columnsForFirstResultRow = resultTable.get(0).getColumns();

             for (int i = 0; i < columnsForFirstResultRow.size(); i++) {

                 if (StringUtils.equals(firstSortColumn, columnsForFirstResultRow.get(i).getPropertyName())) {

                     firstSortColumnIdx = i;

                     break;

                 }

             }

             multipleValueLookupForm.setColumnToSortIndex(firstSortColumnIdx);

         }

         else {

             // don't know how results were sorted, so we just say -1

             multipleValueLookupForm.setColumnToSortIndex(-1);

         }

         // we just performed the lookup, so we're on the first page (indexed from 0)

         multipleValueLookupForm.jumpToFirstPage(resultTable.size(), maxRowsPerPage);

         SequenceAccessorService sas = KNSServiceLocator.getSequenceAccessorService();

         Long nextSeq = sas.getNextAvailableSequenceNumber(KNSConstants.LOOKUP_RESULTS_SEQUENCE); 

         String lookupResultsSequenceNumber = nextSeq.toString();

         multipleValueLookupForm.setLookupResultsSequenceNumber(lookupResultsSequenceNumber);

         try {

             LookupResultsService lookupResultsService = KNSServiceLocator.getLookupResultsService();

             lookupResultsService.persistResultsTable(lookupResultsSequenceNumber, resultTable,

                     GlobalVariables.getUserSession().getPerson().getPrincipalId());

         }

         catch (Exception e) {

             LOG.error("error occured trying to persist multiple lookup results", e);

             throw new RuntimeException("error occured trying to persist multiple lookup results");

         }

         // since new search, nothing's checked

         multipleValueLookupForm.setCompositeObjectIdMap(new HashMap<String, String>());

         return displayList;

     }

     /**

      * This method performs the operations necessary for a multiple value lookup to switch to another page of results and rerender the page

      * @param multipleValueLookupForm

      * @param maxRowsPerPage

      * @return a list of result rows, used by the UI to render the page

      */

     protected List<ResultRow> switchToPage(MultipleValueLookupForm multipleValueLookupForm, int maxRowsPerPage) {

         String lookupResultsSequenceNumber = multipleValueLookupForm.getLookupResultsSequenceNumber();

         List<ResultRow> resultTable = null;

         try {

             resultTable = KNSServiceLocator.getLookupResultsService().retrieveResultsTable(lookupResultsSequenceNumber, GlobalVariables.getUserSession().getPerson().getPrincipalId());

         }

         catch (Exception e) {

             LOG.error("error occured trying to retrieve multiple lookup results", e);

             throw new RuntimeException("error occured trying to retrieve multiple lookup results");

         }

         multipleValueLookupForm.jumpToPage(multipleValueLookupForm.getSwitchToPageNumber(), resultTable.size(), maxRowsPerPage);

         multipleValueLookupForm.setColumnToSortIndex(Integer.parseInt(multipleValueLookupForm.getPreviouslySortedColumnIndex()));

         multipleValueLookupForm.setCompositeObjectIdMap(LookupUtils.generateCompositeSelectedObjectIds(multipleValueLookupForm.getPreviouslySelectedObjectIdSet(),

                 multipleValueLookupForm.getDisplayedObjectIdSet(), multipleValueLookupForm.getSelectedObjectIdSet()));

         return resultTable;

     }

     /**

      * This method performs the operations necessary for a multiple value lookup to sort results and rerender the page

      * 

      * @param multipleValueLookupForm

      * @param maxRowsPerPage

      * @return a list of result rows, used by the UI to render the page

      */

     protected List<ResultRow> sort(MultipleValueLookupForm multipleValueLookupForm, int maxRowsPerPage) {

         String lookupResultsSequenceNumber = multipleValueLookupForm.getLookupResultsSequenceNumber();

         LookupResultsService lookupResultsService = KNSServiceLocator.getLookupResultsService();

         List<ResultRow> resultTable = null;

         try {

             resultTable = lookupResultsService.retrieveResultsTable(lookupResultsSequenceNumber, GlobalVariables.getUserSession().getPerson().getPrincipalId());

         }

         catch (Exception e) {

             LOG.error("error occured trying to retrieve multiple lookup results", e);

             throw new RuntimeException("error occured trying to retrieve multiple lookup results");

         }

         int columnToSortOn = multipleValueLookupForm.getColumnToSortIndex();

         int columnCurrentlySortedOn = Integer.parseInt(multipleValueLookupForm.getPreviouslySortedColumnIndex());

         // if columnCurrentlySortedOn is -1, that means that we don't know which column we were originally sorting on

         // after a search, it's hard to tell which of the columns we're sorted on,

         if (columnToSortOn == columnCurrentlySortedOn) {

             // we're already sorted on the same column that the user clicked on, so we reverse the list

             Collections.reverse(resultTable);

         }

         else {

             // sorting on a different column, so we have to sort

             // HACK ALERT for findBestValueComparatorForColumn, since there's no central place to know

             // which comparator we should use to compare values in a column

             Collections.sort(resultTable, new BeanComparator("columns[" + columnToSortOn + "].propertyValue", LookupUtils.findBestValueComparatorForColumn(resultTable, columnToSortOn)));

         }

         // repersist the list

         try {

             lookupResultsService.persistResultsTable(lookupResultsSequenceNumber, resultTable, 

                     GlobalVariables.getUserSession().getPerson().getPrincipalId());

         }

         catch (Exception e) {

             LOG.error("error occured trying to persist multiple lookup results", e);

             throw new RuntimeException("error occured trying to persist multiple lookup results");

         }

         // we just performed the sort, so go back to first page

         multipleValueLookupForm.jumpToFirstPage(resultTable.size(), maxRowsPerPage);

         multipleValueLookupForm.setCompositeObjectIdMap(LookupUtils.generateCompositeSelectedObjectIds(multipleValueLookupForm.getPreviouslySelectedObjectIdSet(),

                 multipleValueLookupForm.getDisplayedObjectIdSet(), multipleValueLookupForm.getSelectedObjectIdSet()));

         return resultTable;

     }

     /**

      * This method performs the operations necessary for a multiple value lookup keep track of which results have been selected to be returned

      * to the calling document.  Note, this method does not actually requery for the results.

      * 

      * @param multipleValueLookupForm

      */

     protected void prepareToReturnSelectedResultBOs(MultipleValueLookupForm multipleValueLookupForm) {

         String lookupResultsSequenceNumber = multipleValueLookupForm.getLookupResultsSequenceNumber();

         if (StringUtils.isBlank(lookupResultsSequenceNumber)) {

             // pressed return before searching

             return;

         }

         Map<String, String> compositeObjectIdMap = LookupUtils.generateCompositeSelectedObjectIds(multipleValueLookupForm.getPreviouslySelectedObjectIdSet(),

                 multipleValueLookupForm.getDisplayedObjectIdSet(), multipleValueLookupForm.getSelectedObjectIdSet());

         Set<String> compositeObjectIds = compositeObjectIdMap.keySet();

         try {

             LookupResultsService lookupResultsService = KNSServiceLocator.getLookupResultsService();

             lookupResultsService.persistSelectedObjectIds(lookupResultsSequenceNumber, compositeObjectIds,

                     GlobalVariables.getUserSession().getPerson().getPrincipalId());

         }

         catch (Exception e) {

             LOG.error("error occured trying to retrieve selected multiple lookup results", e);

             throw new RuntimeException("error occured trying to retrieve selected multiple lookup results");

         }

     }

     /**

      * This method performs the operations necessary for a multiple value lookup to return no results to the calling page

      * 

      * @param multipleValueLookupForm

      */

     protected void prepareToReturnNone(MultipleValueLookupForm multipleValueLookupForm) {

         String lookupResultsSequenceNumber = multipleValueLookupForm.getLookupResultsSequenceNumber();

         try {

             if (StringUtils.isNotBlank(lookupResultsSequenceNumber)) {

                 // we're returning nothing, so we try to get rid of stuff

                 LookupResultsService lookupResultsService = KNSServiceLocator.getLookupResultsService();

                 lookupResultsService.clearPersistedLookupResults(lookupResultsSequenceNumber);

                 multipleValueLookupForm.setLookupResultsSequenceNumber(null);

             }

         }

         catch (Exception e) {

             // not a big deal, continue on and purge w/ a batch job

             LOG.error("error occured trying to clear lookup results seq nbr " + lookupResultsSequenceNumber, e);

         }

     }

     /**

      * This method performs the operations necessary for a multiple value lookup to export the rows via display tag

      * 

      * Note: this method assumes that the export will be opened in a new browser window, therefore, persisting the selected

      * checkboxes will not be needed.

      * 

      * @param multipleValueLookupForm

      * @return a list of result rows, to be used by display tag to render the results

      */

     protected List<ResultRow> prepareToExport(MultipleValueLookupForm multipleValueLookupForm) {

         String lookupResultsSequenceNumber = multipleValueLookupForm.getLookupResultsSequenceNumber();

         List<ResultRow> resultTable = null;

         try {

             LookupResultsService lookupResultsService = KNSServiceLocator.getLookupResultsService();

             resultTable = lookupResultsService.retrieveResultsTable(lookupResultsSequenceNumber, GlobalVariables.getUserSession().getPerson().getPrincipalId());

         }

         catch (Exception e) {

             LOG.error("error occured trying to export multiple lookup results", e);

             throw new RuntimeException("error occured trying to export multiple lookup results");

         }

         return resultTable;

     }

     /**

      * This method performs the operations necessary for a multiple value lookup to select all of the results and rerender the page

      * @param multipleValueLookupForm

      * @param maxRowsPerPage

      * @return a list of result rows, used by the UI to render the page

      */

     protected List<ResultRow> selectAll(MultipleValueLookupForm multipleValueLookupForm, int maxRowsPerPage) {

         String lookupResultsSequenceNumber = multipleValueLookupForm.getLookupResultsSequenceNumber();

         List<ResultRow> resultTable = null;

         try {

             LookupResultsService lookupResultsService = KNSServiceLocator.getLookupResultsService();

             resultTable = lookupResultsService.retrieveResultsTable(lookupResultsSequenceNumber, GlobalVariables.getUserSession().getPerson().getPrincipalId());

         }

         catch (Exception e) {

             LOG.error("error occured trying to export multiple lookup results", e);

             throw new RuntimeException("error occured trying to export multiple lookup results");

         }

         Map<String, String> selectedObjectIds = new HashMap<String, String>();

         for (ResultRow row : resultTable) {

             String objId = row.getObjectId();

             InputHtmlData returnUrl = (InputHtmlData) row.getReturnUrlHtmlData();

             returnUrl.setChecked(InputHtmlData.CHECKBOX_CHECKED_VALUE);

             row.setReturnUrl(returnUrl.constructCompleteHtmlTag());

             if(objId != null){

                     selectedObjectIds.put(objId, objId);

             }

         }

         multipleValueLookupForm.jumpToPage(multipleValueLookupForm.getViewedPageNumber(), resultTable.size(), maxRowsPerPage);

         multipleValueLookupForm.setColumnToSortIndex(Integer.parseInt(multipleValueLookupForm.getPreviouslySortedColumnIndex()));

         multipleValueLookupForm.setCompositeObjectIdMap(selectedObjectIds);

         return resultTable;

     }

     @Override

     public ActionForward clearValues(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {

         MultipleValueLookupForm multipleValueLookupForm = (MultipleValueLookupForm) form;

         // call the following methods to clear the persisted results

         prepareToReturnNone(multipleValueLookupForm);

         return super.clearValues(mapping, form, request, response);

     }

     /**

      * This method performs the operations necessary for a multiple value lookup to unselect all of the results and rerender the page

      * @param multipleValueLookupForm

      * @param maxRowsPerPage

      * @return a list of result rows, used by the UI to render the page

      */

     protected List<ResultRow> unselectAll(MultipleValueLookupForm multipleValueLookupForm, int maxRowsPerPage) {

         String lookupResultsSequenceNumber = multipleValueLookupForm.getLookupResultsSequenceNumber();

         List<ResultRow> resultTable = null;

         try {

             LookupResultsService lookupResultsService = KNSServiceLocator.getLookupResultsService();

             resultTable = lookupResultsService.retrieveResultsTable(lookupResultsSequenceNumber, GlobalVariables.getUserSession().getPerson().getPrincipalId());

         }

         catch (Exception e) {

             LOG.error("error occured trying to export multiple lookup results", e);

             throw new RuntimeException("error occured trying to export multiple lookup results");

         }

         Map<String, String> selectedObjectIds = new HashMap<String, String>();

         // keep map empty since we're not selecting anything

         multipleValueLookupForm.jumpToPage(multipleValueLookupForm.getViewedPageNumber(), resultTable.size(), maxRowsPerPage);

         multipleValueLookupForm.setColumnToSortIndex(Integer.parseInt(multipleValueLookupForm.getPreviouslySortedColumnIndex()));

         multipleValueLookupForm.setCompositeObjectIdMap(selectedObjectIds);

         return resultTable;

     }

     /**

      * This method computes the max number of rows that should be rendered per page for a multiple value lookup.

      * 

      * This method first looks for an application parameter in FS_PARM_T, group SYSTEM, multipleValueLookupResultsPerPage

      * 

      * if someone wants to implement something where a user can decide how many results to display per page, 

      * this method is the place to do it.  Make this method read form values to determine the max rows per page based on the user inputs

      * 

      * @see org.kuali.rice.kns.util.KNSConstants.SystemGroupParameterNames#MULTIPLE_VALUE_LOOKUP_RESULTS_PER_PAGE

      * @see #DEFAULT_MAX_ROWS_PER_PAGE

      * @param multipleValueLookupForm the form

      * @return

      */

     protected int getMaxRowsPerPage(MultipleValueLookupForm multipleValueLookupForm) {

         Integer appMaxRowsPerPage = LookupUtils.getApplicationMaximumSearchResulsPerPageForMultipleValueLookups();

         if (appMaxRowsPerPage == null) {

             LOG.warn("Couldn't find application results per page for MV lookups.  Using default of " + DEFAULT_MAX_ROWS_PER_PAGE);

             appMaxRowsPerPage = new Integer(DEFAULT_MAX_ROWS_PER_PAGE);

         }

         return appMaxRowsPerPage;

     }

 }