/**
    * Copyright 2005-2015 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 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.api.util.RiceConstants;
  import org.kuali.rice.kns.lookup.HtmlData;
  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.service.KNSServiceLocator;
  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;
  import org.kuali.rice.krad.lookup.CollectionIncomplete;
  import org.kuali.rice.krad.service.KRADServiceLocator;
  import org.kuali.rice.krad.service.SequenceAccessorService;
  import org.kuali.rice.krad.util.GlobalVariables;
  import org.kuali.rice.krad.util.KRADConstants;
  import org.kuali.rice.krad.util.UrlFactory;
  
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  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;
  
  /**
   * This class serves as the struts action for implementing multiple value lookups
   *
   * @deprecated KNS Struts deprecated, use KRAD and the Spring MVC framework.
   */
  @Deprecated
  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(KRADConstants.SEARCH_METHOD);
          }
  
          Lookupable kualiLookupable = multipleValueLookupForm.getLookupable();
          if (kualiLookupable == null) {
              LOG.error("Lookupable is null.");
              throw new RuntimeException("Lookupable is null.");
          }
  
          Collection displayList = new ArrayList();
          ArrayList<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(KRADConstants.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(KRADConstants.SEARCH_LIST_REQUEST_KEY) != null) {
             GlobalVariables.getUserSession().removeObject(request.getParameter(KRADConstants.SEARCH_LIST_REQUEST_KEY));
         }
         request.setAttribute(KRADConstants.SEARCH_LIST_REQUEST_KEY, GlobalVariables.getUserSession().addObjectWithGeneratedKey(resultTable, KRADConstants.SEARCH_LIST_KEY_PREFIX));
 
         request.getParameter(KRADConstants.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
      */
     @Override
     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
      */
     @Override
     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(KRADConstants.LOOKUP_RESULTS_BO_CLASS_NAME, multipleValueLookupForm.getBusinessObjectClassName());
         parameters.put(KRADConstants.LOOKUP_RESULTS_SEQUENCE_NUMBER, multipleValueLookupForm.getLookupResultsSequenceNumber());
         parameters.put(KRADConstants.DOC_FORM_KEY, multipleValueLookupForm.getFormKey());
         parameters.put(KRADConstants.DISPATCH_REQUEST_PARAMETER, KRADConstants.RETURN_METHOD_TO_CALL);
         parameters.put(KRADConstants.REFRESH_CALLER, KRADConstants.MULTIPLE_VALUE);
         parameters.put(KRADConstants.ANCHOR, multipleValueLookupForm.getLookupAnchor());
         parameters.put(KRADConstants.LOOKED_UP_COLLECTION_NAME, multipleValueLookupForm.getLookedUpCollectionName());
         if(multipleValueLookupForm.getDocNum() != null){
             parameters.put(KRADConstants.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 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(KRADConstants.DOC_FORM_KEY, multipleValueLookupForm.getFormKey());
         parameters.put(KRADConstants.DISPATCH_REQUEST_PARAMETER, KRADConstants.RETURN_METHOD_TO_CALL);
         parameters.put(KRADConstants.REFRESH_CALLER, KRADConstants.MULTIPLE_VALUE);
         parameters.put(KRADConstants.ANCHOR, multipleValueLookupForm.getLookupAnchor());
         if(multipleValueLookupForm.getDocNum() != null){
             parameters.put(KRADConstants.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(KRADConstants.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()));
         Map<String, String> selectedIds = LookupUtils.generateCompositeSelectedObjectIds(multipleValueLookupForm.getPreviouslySelectedObjectIdSet(),
                 multipleValueLookupForm.getDisplayedObjectIdSet(), multipleValueLookupForm.getSelectedObjectIdSet());
 
         multipleValueLookupForm.setCompositeObjectIdMap(selectedIds);
 
         // Check the boxes that are selected on the page
         for (ResultRow row : resultTable) {
             String objId = row.getObjectId();
             for (Map.Entry<String, String> entry : selectedIds.entrySet()) {
                 String selectedId = entry.getValue();
                 if (objId.equalsIgnoreCase(selectedId)) {
                     HtmlData.InputHtmlData returnUrl = (HtmlData.InputHtmlData) row.getReturnUrlHtmlData();
                     returnUrl.setChecked(HtmlData.InputHtmlData.CHECKBOX_CHECKED_VALUE);
                     row.setReturnUrl(returnUrl.constructCompleteHtmlTag());
                 }
             }
         }
         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();
             HtmlData.InputHtmlData returnUrl = (HtmlData.InputHtmlData) row.getReturnUrlHtmlData();
             returnUrl.setChecked(HtmlData.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.krad.util.KRADConstants.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;
     }
 }