package edu.internet2.middleware.grouper.pspng;
   
   /*******************************************************************************
    * Copyright 2015 Internet2
    * 
    * 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.
   ******************************************************************************/
  
  import java.io.IOException;
  import java.io.Reader;
  import java.io.StringReader;
  import java.util.*;
  
  import com.unboundid.ldap.sdk.Filter;
  import com.unboundid.ldap.sdk.LDAPException;
  import org.apache.commons.lang.StringUtils;
  import org.ldaptive.*;
  import org.ldaptive.io.LdifReader;
  
  import edu.internet2.middleware.subject.Subject;
  import static edu.internet2.middleware.grouper.pspng.PspUtils.*;
  
  
  
  /**
   * This class is the workhorse for provisioning LDAP groups from
   * grouper.
   *
   * @author bert
   *
   */
  public class LdapGroupProvisioner extends LdapProvisioner<LdapGroupProvisionerConfiguration> {
  
    public LdapGroupProvisioner(String provisionerName, LdapGroupProvisionerConfiguration config, boolean fullSyncMode) {
      super(provisionerName, config, fullSyncMode);
  
      LOG.debug("Constructing LdapGroupProvisioner: {}", provisionerName);
    }
  
    public static Class<? extends ProvisionerConfiguration> getPropertyClass() {
      return LdapGroupProvisionerConfiguration.class;
    }
  
  
    @Override
    protected void addMembership(GrouperGroupInfo grouperGroupInfo, LdapGroup ldapGroup,
        Subject subject, LdapUser ldapUser) throws PspException {
  
      // TODO: Look in memory cache to see if change is necessary:
      // a) User object's group-listing attribute
      // or b) if the group-membership attribute is being fetched
  
      if ( ldapUser == null ) {
        LOG.warn("{}: Skipping adding membership to group {} because ldap user does not exist: {}",
            new Object[]{getDisplayName(), grouperGroupInfo, subject});
        return;
      }
  
      if ( ldapGroup == null ) {
        // Create the group if it hasn't been created yet. List the user so that creation can be combined
        // with membership addition
  
        // This will normally occur when the schema requires members and group-creation is delayed until
        // the this method is being called to add the first member
        ldapGroup = createGroup(grouperGroupInfo, Arrays.asList(subject));
        cacheGroup(grouperGroupInfo, ldapGroup);
      }
      else {
        String membershipAttributeValue = evaluateJexlExpression("MemberAttributeValue", config.getMemberAttributeValueFormat(), subject, ldapUser, grouperGroupInfo, ldapGroup);
        if ( membershipAttributeValue != null ) {
          scheduleGroupModification(grouperGroupInfo, ldapGroup, AttributeModificationType.ADD, Arrays.asList(membershipAttributeValue));
        }
      }
    }
  
  
    protected void scheduleGroupModification(GrouperGroupInfo grouperGroupInfo, LdapGroup ldapGroup, AttributeModificationType modType, Collection<String> membershipValuesToChange) {
      String attributeName = config.getMemberAttributeName();
  
      for ( String value : membershipValuesToChange )
        // ADD/REMOVE <value> to/from <attribute> of <group>
        LOG.info("Will change LDAP: {} {} {} {} of {}",
            new Object[] {modType, value,
            modType == AttributeModificationType.ADD ? "to" : "from",
            attributeName, ldapGroup});
  
      scheduleLdapModification(
          new ModifyRequest(
              ldapGroup.getLdapObject().getDn(),
             new AttributeModification(
                 modType,
                 new LdapAttribute(attributeName, membershipValuesToChange.toArray(new String[0])))));
   }
 
   @Override
   protected void deleteMembership(GrouperGroupInfo grouperGroupInfo, LdapGroup ldapGroup ,
       Subject subject, LdapUser ldapUser) throws PspException {
     if ( ldapGroup  == null ) {
       LOG.warn("{}: Ignoring request to remove {} from a group that doesn't exist: {}",
           new Object[]{getDisplayName(), subject.getId(), grouperGroupInfo});
       return;
     }
 
     if ( ldapUser == null ) {
       LOG.warn("{}: Skipping removing membership from group {} because ldap user does not exist: {}",
           new Object[]{getDisplayName(), grouperGroupInfo, subject});
       return;
     }
 
     // TODO: Look in memory cache to see if change is necessary:
     // a) User object's group-listing attribute
     // or b) if the group-membership attribute is being fetched
 
     String membershipAttributeValue = evaluateJexlExpression("MemberAttributeValue", config.getMemberAttributeValueFormat(), subject, ldapUser, grouperGroupInfo, ldapGroup);
 
     if ( membershipAttributeValue != null ) {
       scheduleGroupModification(grouperGroupInfo, ldapGroup, AttributeModificationType.REMOVE, Arrays.asList(membershipAttributeValue));
     }
   }
 
   @Override
   protected boolean doFullSync(
       GrouperGroupInfo grouperGroupInfo, LdapGroup ldapGroup ,
       Set<Subject> correctSubjects, Map<Subject, LdapUser> tsUserMap,
       Set<LdapUser> correctTSUsers,
       JobStatistics stats) throws PspException {
 
     stats.totalCount.set(correctSubjects.size());
 
     // Looking for bug
     // Make sure the group we've been passed has been fetched with the membership attribute
     if ( ldapGroup != null )
       ldapGroup.getLdapObject().getStringValues(config.getMemberAttributeName());
 
     // If the group does not exist yet, then create it with all the correct members
     if ( ldapGroup  == null ) {
 
       // If the schema requires member attribute, then don't do anything if there aren't any members
       if ( config.areEmptyGroupsSupported() ) {
         if ( correctSubjects.size() == 0 ) {
           LOG.info("{}: Nothing to do because empty group already not present in ldap system", getDisplayName() );
           return false;
         }
       }
 
       ldapGroup  = createGroup(grouperGroupInfo, correctSubjects);
       stats.insertCount.set(correctSubjects.size());
 
       // Make note of the group if it was created
       if ( ldapGroup != null ) {
         cacheGroup(grouperGroupInfo, ldapGroup);
       }
       return true;
     } else {
         // The LDAP group exists, let's make sure the non-membership attributes are still accurate
         ldapGroup = updateGroupFromTemplate(grouperGroupInfo, ldapGroup);
         cacheGroup(grouperGroupInfo, ldapGroup);
     }
 
     // Delete an empty group if the schema requires a membership
     if ( !config.areEmptyGroupsSupported() && correctSubjects.size() == 0 ) {
       LOG.info("{}: Deleting empty group because schema requires its member attribute", getDisplayName());
       deleteGroup(grouperGroupInfo, ldapGroup);
 
       // Update stats with the number of values removed by group deletion
       Collection<String> membershipValues = ldapGroup.getLdapObject().getStringValues(config.getMemberAttributeName());
       stats.deleteCount.set(membershipValues.size());
 
       return true;
     }
 
     Set<String> correctMembershipValues = getStringSet(config.isMemberAttributeCaseSensitive());
 
     for ( Subject correctSubject: correctSubjects ) {
       String membershipAttributeValue = evaluateJexlExpression("MemberAttributeValue", config.getMemberAttributeValueFormat(), correctSubject, tsUserMap.get(correctSubject), grouperGroupInfo, ldapGroup);
 
       if ( membershipAttributeValue != null ) {
         correctMembershipValues.add(membershipAttributeValue);
       }
     }
 
     Collection<String> currentMembershipValues = getStringSet(config.isMemberAttributeCaseSensitive(), ldapGroup.getLdapObject().getStringValues(config.getMemberAttributeName()));
 
     LOG.info("{}: Full-sync comparison for {}: Target-subject count: Correct/Actual: {}/{}",
             new Object[] {getDisplayName(), grouperGroupInfo, correctMembershipValues.size(), currentMembershipValues.size()});
 
     LOG.debug("{}: Full-sync comparison: Correct: {}", getDisplayName(), correctMembershipValues);
     LOG.debug("{}: Full-sync comparison: Actual: {}", getDisplayName(), currentMembershipValues);
 
     // EXTRA = CURRENT - CORRECT
       Collection<String> extraValues = subtractStringCollections(
               config.isMemberAttributeCaseSensitive(), currentMembershipValues, correctMembershipValues);
 
       stats.deleteCount.set(extraValues.size());
 
       LOG.info("{}: Group {} has {} extra values",
           new Object[] {getDisplayName(), grouperGroupInfo, extraValues.size()});
       if ( extraValues.size() > 0 ) {
         getLdapSystem().performLdapModify(
                 new ModifyRequest(
                         ldapGroup.dn,
                         new AttributeModification(
                                 AttributeModificationType.REMOVE,
                                 new LdapAttribute(config.getMemberAttributeName(),extraValues.toArray(new String[0])))),
                 config.isMemberAttributeCaseSensitive(),
                 true);
       }
 
     // MISSING = CORRECT - CURRENT
       Collection<String> missingValues = subtractStringCollections(
               config.isMemberAttributeCaseSensitive(), correctMembershipValues, currentMembershipValues);
 
       stats.insertCount.set(missingValues.size());
 
       LOG.info("{}: Group {} has {} missing values",
           new Object[]{getDisplayName(), grouperGroupInfo, missingValues.size()});
       if ( missingValues.size() > 0 ) {
         getLdapSystem().performLdapModify(
                 new ModifyRequest(
                         ldapGroup.dn,
                         new AttributeModification(
                                 AttributeModificationType.ADD,
                                 new LdapAttribute(config.getMemberAttributeName(),missingValues.toArray(new String[0])))),
                 config.isMemberAttributeCaseSensitive(),
                 true);
 
     }
 
     return extraValues.size()>0 || missingValues.size()>0;
   }
 
   /**
    * This method compares the existing LdapGroup to how the groupCreationTemplate might have
    * changed due to group changes (eg, a changed group name) or due to template changes
    * @param grouperGroupInfo
    * @param existingLdapGroup
    * @return An up-to-date LdapGroup: either existingLdapGroup if no changes were needed, or a newly-read group
    */
   protected LdapGroupg/LdapGroup.html#LdapGroup">LdapGroup updateGroupFromTemplate(GrouperGroupInfo grouperGroupInfo, LdapGroup existingLdapGroup) throws PspException {
     LOG.debug("{}: Making sure (non-membership) attributes of group are up to date: {}", getDisplayName(), existingLdapGroup.dn);
 
     try {
       String ldifFromTemplate = getGroupLdifFromTemplate(grouperGroupInfo);
       LdapEntry ldapEntryFromTemplate = getLdapEntryFromLdif(ldifFromTemplate);
 
       ensureLdapOusExist(ldapEntryFromTemplate.getDn(), false);
       if ( getLdapSystem().makeLdapObjectCorrect(ldapEntryFromTemplate, existingLdapGroup.ldapObject.ldapEntry, config.isMemberAttributeCaseSensitive()) ) {
         LdapGroup result = fetchTargetSystemGroup(grouperGroupInfo);
         return result;
       }
       else {
         return existingLdapGroup;
       }
     }
     catch (PspException e) {
       LOG.error("{}: Problem checking and updating group's template attributes", getDisplayName(), e);
       throw e;
     }
     catch (IOException e) {
       LOG.error("{}: Problem checking and updating group's tempalte attributes", getDisplayName(), e);
       throw new PspException("IO Exception while checking and updating group's template attributes", e);
     }
   }
 
 
 
   @Override
 	protected void doFullSync_cleanupExtraGroups(JobStatistics stats) throws PspException {
 
     // (1) Get all the groups that are in LDAP
     String filterString = config.getAllGroupSearchFilter();
     if ( StringUtils.isEmpty(filterString) ) {
       LOG.error("{}: Cannot cleanup extra groups without a configured all-group search filter", getDisplayName());
       return;
     }
 
     String baseDn = config.getGroupSearchBaseDn();
 
     if ( StringUtils.isEmpty(baseDn)) {
       LOG.error("{}: Cannot cleanup extra groups without a configured group-search base dn", getDisplayName());
       return;
     }
 
     // Get all the LDAP Groups that match the filter
     List<LdapObject> allProvisionedGroups
             = getLdapSystem().performLdapSearchRequest(
             -1, baseDn, SearchScope.SUBTREE,
                     Arrays.asList(getLdapAttributesToFetch()), filterString);
 
 
     // See what LDAP Groups match the correct list of groups
 
     Collection<GrouperGroupInfo> groupsThatShouldBeProvisioned = getAllGroupsForProvisioner();
     Map<GrouperGroupInfo, LdapGroup> ldapGroupsThatShouldBeProvisioned = fetchTargetSystemGroupsInBatches(groupsThatShouldBeProvisioned);
 
     Set<String> correctGroupDNs = new TreeSet<>(String.CASE_INSENSITIVE_ORDER);
     for(LdapGroup correctLdapGroup : ldapGroupsThatShouldBeProvisioned.values()) {
       String correctLdapGroupDn = correctLdapGroup.getLdapObject().getDn();
       correctGroupDNs.add(correctLdapGroupDn);
     }
 
 
     List<LdapObject> groupsToDelete = new ArrayList<LdapObject>();
     for (LdapObject aProvisionedGroup : allProvisionedGroups) {
       if ( ! correctGroupDNs.contains(aProvisionedGroup.getDn()) ) {
         groupsToDelete.add(aProvisionedGroup);
       }
     }
 
     LOG.info("{}: There are {} groups that we should delete", getDisplayName(), groupsToDelete.size());
 
     for ( LdapObject groupToRemove : groupsToDelete ) {
       int numMembershipsBeingDeleted = groupToRemove.getStringValues(config.getMemberAttributeName()).size();
       stats.deleteCount.addAndGet(numMembershipsBeingDeleted);
 
       getLdapSystem().performLdapDelete(groupToRemove.getDn());
     }
 
   }
 
 
   @Override
   protected LdapGroup createGroup(GrouperGroupInfo grouperGroup, Collection<Subject> initialMembers) throws PspException {
     if ( !config.areEmptyGroupsSupported() && initialMembers.size() == 0 ) {
       LOG.warn("Not Creating LDAP group because empty groups are not supported: {}", grouperGroup);
       return null;
     }
 
     LOG.info("Creating LDAP group for GrouperGroup: {} ", grouperGroup);
     String ldif = getGroupLdifFromTemplate(grouperGroup);
 
     // If initialMembers were specified, then add the ldif necessary to include them
     if ( initialMembers != null && initialMembers.size() > 0 ) {
 
       // Find all the values for the membership attribute
       Collection<String> membershipValues = new HashSet<String>(initialMembers.size());
       for ( Subject subject : initialMembers ) {
         LdapUser ldapUser = getTargetSystemUser(subject);
         if ( ldapUser != null ) {
           String membershipAttributeValue = evaluateJexlExpression("MemberAttributeValue", config.getMemberAttributeValueFormat(), subject, ldapUser, grouperGroup, null);
           if ( membershipAttributeValue != null ) {
             membershipValues.add(membershipAttributeValue);
           }
         }
       }
 
       StringBuilder ldifForMemberships = new StringBuilder();
       for ( String attributeValue : membershipValues ) {
         ldifForMemberships.append(String.format("%s: %s\n", config.getMemberAttributeName(), attributeValue));
       }
       ldif = ldif.concat("\n");
       ldif = ldif.concat(ldifForMemberships.toString());
     }
 
     Connection conn = getLdapSystem().getLdapConnection();
     try {
       LOG.debug("{}: LDIF for new group (with partial DN): {}", getDisplayName(), ldif.replaceAll("\\n", "||"));
       LdapEntry ldifEntry = getLdapEntryFromLdif(ldif);
 
       // Check to see if any attributes ended up without any values/
       for ( String attributeName : ldifEntry.getAttributeNames() ) {
         LdapAttribute attribute = ldifEntry.getAttribute(attributeName);
         if ( LdapSystem.attributeHasNoValues(attribute) ) {
           LOG.warn("{}: LDIF for new group did not define any values for {}", getDisplayName(), attributeName);
           ldifEntry.removeAttribute(attributeName);
         }
       }
       LOG.debug("{}: Adding group: {}", getDisplayName(), ldifEntry);
       
       performLdapAdd(ldifEntry);
       
       // Read the group that was just created
       LOG.debug("Reading group that was just added to ldap server: {}", grouperGroup);
       LdapGroup result = fetchTargetSystemGroup(grouperGroup);
 
       if ( result == null ) {
         LOG.error("{}: Group could not be found after it was created: {}", getDisplayName(), grouperGroup);
       }
       return result;
     } catch (PspException e) {
       LOG.error("Problem while creating new group: {}", ldif, e);
       throw e;
     } catch ( IOException e ) {
       LOG.error("IO problem while creating group: {}", ldif, e);
       throw new PspException("IO problem while creating group: %s", e.getMessage());
     }
     finally {
       conn.close();
     }
   }
 
   /**
    * This returns an LdapEntry from the provided ldif. NOTE: The DN of the LDIF is extended
    * with the configuration's groupCreationBaseDn.
    *
    * @param ldif
    * @return
    * @throws IOException
    */
   private LdapEntry getLdapEntryFromLdif(String ldif) throws IOException {
     Reader reader = new StringReader(ldif);
     LdifReader ldifReader = new LdifReader(reader);
     SearchResult ldifResult = ldifReader.read();
     LdapEntry ldifEntry = ldifResult.getEntry();
 
     // Update DN to be relative to groupCreationBaseDn
     String actualDn = String.format("%s,%s", ldifEntry.getDn(),config.getGroupCreationBaseDn());
     ldifEntry.setDn(actualDn);
     return ldifEntry;
   }
 
   /**
    * Fills in the GroupCreationLdifTemplate for the provided group
    * @param grouperGroup
    * @return
    * @throws PspException
    */
   private String getGroupLdifFromTemplate(GrouperGroupInfo grouperGroup) throws PspException {
     String ldif = config.getGroupCreationLdifTemplate();
     ldif = ldif.replaceAll("\\|\\|", "\n");
     ldif = evaluateJexlExpression("GroupTemplate", ldif, null, null, grouperGroup, null);
     ldif = sanityCheckDnAttributesOfLdif(ldif, "Group ldif for %s", grouperGroup);
 
     return ldif;
   }
 
   @Override
   protected Map<GrouperGroupInfo, LdapGroup> fetchTargetSystemGroups(
       Collection<GrouperGroupInfo> grouperGroupsToFetch) throws PspException {
     if ( grouperGroupsToFetch.size() > config.getGroupSearch_batchSize() )
       throw new IllegalArgumentException("LdapGroupProvisioner.fetchTargetSystemGroups: invoked with too many groups to fetch");
     
     // If this is a full-sync provisioner, then we want to make sure we get the member attribute of the
     // group so we see all members.
     String[] returnAttributes = getLdapAttributesToFetch();
 
     if ( grouperGroupsToFetch.size() > 1 && config.isBulkGroupSearchingEnabled() ) {
       StringBuilder combinedLdapFilter = new StringBuilder();
 
       // Start the combined ldap filter as an OR-query
       combinedLdapFilter.append("(|");
 
       for (GrouperGroupInfo grouperGroup : grouperGroupsToFetch) {
         SearchFilter f = getGroupLdapFilter(grouperGroup);
         String groupFilterString = f.format();
 
         // Wrap the subject's filter in (...) if it doesn't start with (
         if (groupFilterString.startsWith("("))
           combinedLdapFilter.append(groupFilterString);
         else
           combinedLdapFilter.append('(').append(groupFilterString).append(')');
       }
       combinedLdapFilter.append(')');
 
       // Actually do the search
       List<LdapObject> searchResult;
 
       LOG.debug("{}: Searching for {} groups with:: {}",
               new Object[]{getDisplayName(), grouperGroupsToFetch.size(), combinedLdapFilter});
 
       try {
         searchResult = getLdapSystem().performLdapSearchRequest(
                 -1, config.getGroupSearchBaseDn(), SearchScope.SUBTREE,
                 Arrays.asList(returnAttributes),
                 combinedLdapFilter.toString());
       } catch (PspException e) {
         LOG.error("Problem fetching groups with filter '{}' on base '{}'",
                 new Object[]{combinedLdapFilter, config.getGroupSearchBaseDn(), e});
         throw e;
       }
 
       LOG.debug("{}: Group search returned {} groups", getDisplayName(), searchResult.size());
 
       // Now we have a bag of LdapObjects, but we don't know which goes with which grouperGroup.
       // We're going to go through the Grouper Groups and their filters and compare
       // them to the Ldap data we've fetched into memory.
       Map<GrouperGroupInfo, LdapGroup> result = new HashMap<GrouperGroupInfo, LdapGroup>();
 
       Set<LdapObject> matchedFetchResults = new HashSet<LdapObject>();
 
       // For every group we tried to bulk fetch, find the matching LdapObject that came back
       for (GrouperGroupInfo groupToFetch : grouperGroupsToFetch) {
         SearchFilter f = getGroupLdapFilter(groupToFetch);
 
         for (LdapObject aFetchedLdapObject : searchResult) {
           if (aFetchedLdapObject.matchesLdapFilter(f)) {
             result.put(groupToFetch, new LdapGroup(aFetchedLdapObject));
             matchedFetchResults.add(aFetchedLdapObject);
             break;
           }
         }
       }
 
       Set<LdapObject> unmatchedFetchResults = new HashSet<LdapObject>(searchResult);
       unmatchedFetchResults.removeAll(matchedFetchResults);
 
       // We're done if everything matched up
       if ( unmatchedFetchResults.size() == 0 ) {
         return result;
       }
       else {
         for (LdapObject unmatchedFetchResult : unmatchedFetchResults) {
           LOG.warn("{}: Bulk fetch failed (returned unmatchable group data). "
                           + "This can be caused by searching for a DN with escaping or by singleGroupSearchFilter ({}) that are not included "
                           + "in groupSearchAttributes ({})?): {}",
                   new Object[]{getDisplayName(), config.getSingleGroupSearchFilter(), config.getGroupSearchAttributes(), unmatchedFetchResult.getDn()});
         }
         LOG.warn("{}: Slower fetching will be attempted", getDisplayName());
 
         // Fall through to the one-by-one group searching below. This is slower, but doesn't require the
         // result-matching step that just failed
       }
     }
 
     // Do simple ldap searching
     Map<GrouperGroupInfo, LdapGroup> result = new HashMap<GrouperGroupInfo, LdapGroup>();
 
     for (GrouperGroupInfo grouperGroup : grouperGroupsToFetch) {
       SearchFilter groupLdapFilter = getGroupLdapFilter(grouperGroup);
       try {
         LOG.debug("{}: Searching for group {} with:: {}",
                 new Object[]{getDisplayName(), grouperGroup, groupLdapFilter});
 
         // Actually do the search
         List<LdapObject> searchResult = getLdapSystem().performLdapSearchRequest(
                 -1, config.getGroupSearchBaseDn(), SearchScope.SUBTREE,
                 Arrays.asList(returnAttributes),
                 groupLdapFilter);
 
         if (searchResult.size() == 1) {
           LdapObject ldapObject = searchResult.iterator().next();
           LOG.debug("{}: Group search returned {}", getDisplayName(), ldapObject.getDn());
           result.put(grouperGroup, new LdapGroup(ldapObject));
         }
         else if ( searchResult.size() > 1 ){
           LOG.error("{}: Search for group {} with '{}' returned multiple matches: {}",
                   new Object[]{getDisplayName(), grouperGroup, groupLdapFilter, searchResult});
           throw new PspException("Search for ldap group returned multiple matches");
         }
         else if ( searchResult.size() == 0 ) {
           // No match found ==> result will not include an entry for this grouperGroup
           LOG.debug("{}: Group search did not return any results", getDisplayName());
         }
       } catch (PspException e) {
         LOG.error("{}: Problem fetching group with filter '{}' on base '{}'",
                 new Object[]{getDisplayName(), groupLdapFilter, config.getGroupSearchBaseDn(), e});
         throw e;
       }
     }
 
     return result;
 }
 
   private String[] getLdapAttributesToFetch() {
     String returnAttributes[] = config.getGroupSearchAttributes();
     if ( fullSyncMode ) {
       LOG.debug("Fetching membership attribute, too");
       // Add the membership attribute to the list of attributes to fetch
       returnAttributes = Arrays.copyOf(returnAttributes, returnAttributes.length + 1);
       returnAttributes[returnAttributes.length-1] = config.getMemberAttributeName();
     } else {
       LOG.debug("Fetching without membership attribute");
     }
     return returnAttributes;
   }
 
 
   private SearchFilter getGroupLdapFilter(GrouperGroupInfo grouperGroup) throws PspException {
     String result = evaluateJexlExpression("SingleGroupSearchFilter", config.getSingleGroupSearchFilter(), null, null, grouperGroup, null);
     if ( StringUtils.isEmpty(result) )
       throw new RuntimeException("Group searching requires singleGroupSearchFilter to be configured correctly");
 
     // If the filter contains '||', then this filter is requesting parameter substitution
     String filterPieces[] = result.split("\\|\\|");
     SearchFilter filter = new SearchFilter(filterPieces[0]);
     // If the filter is not using ldap-filter parameters, check its syntax
     if ( filterPieces.length == 1 ) {
       try {
         // Use unboundid to sanity-check/parse filter
         Filter.create(result);
       }
       catch (LDAPException e) {
         LOG.warn("{}: Group ldap filter was invalid. " +
                         "Perhaps its filter clauses needed to be escaped with utils.escapeLdapFilter or use ldap-filter positional parameters. " +
                         "Group={}. Bad filter={}. ",
                 new Object[]{getDisplayName(), grouperGroup, result});
 
         // We're going to proceed here just in case the filter-checking logic is too
         // sensitive. The ldap server will eventually see the filter and make its own decision
       }
     } else {
       // Set the positional parameters
 
       for (int i = 1; i < filterPieces.length; i++)
         filter.setParameter(i - 1, filterPieces[i].trim());
     }
 
     LOG.trace("{}: Filter for group {}: {}",
         new Object[] {getDisplayName(), grouperGroup, filter});
 
     return filter;
   }
 
 
   @Override
   protected void deleteGroup(GrouperGroupInfo grouperGroupInfo, LdapGroup ldapGroup)
       throws PspException {
     if ( ldapGroup == null ) {
       LOG.warn("Nothing to do: Unable to delete group {} because the group wasn't found on target system", grouperGroupInfo);
       return;
     }
     
     String dn = ldapGroup.getLdapObject().getDn();
     
     LOG.info("Deleting group {} by deleting DN {}", grouperGroupInfo, dn);
     
     getLdapSystem().performLdapDelete(dn);;
   }
 }