From 2c9165afb08126189ee3367347e7011f89227b7c Mon Sep 17 00:00:00 2001
From: Tim Donohue <tim.donohue@lyrasis.org>
Date: Mon, 18 Sep 2023 10:58:18 -0500
Subject: [PATCH] Replace several usages of allMembers() with count methods to
 avoid performance issues

---
 .../dspace/eperson/EPersonServiceImpl.java    |  7 +++++--
 .../org/dspace/eperson/GroupServiceImpl.java  | 19 ++++++++++++-------
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/dspace-api/src/main/java/org/dspace/eperson/EPersonServiceImpl.java b/dspace-api/src/main/java/org/dspace/eperson/EPersonServiceImpl.java
index 5f17051dbb..ce117282de 100644
--- a/dspace-api/src/main/java/org/dspace/eperson/EPersonServiceImpl.java
+++ b/dspace-api/src/main/java/org/dspace/eperson/EPersonServiceImpl.java
@@ -305,10 +305,13 @@ public class EPersonServiceImpl extends DSpaceObjectServiceImpl<EPerson> impleme
             throw new AuthorizeException(
                     "You must be an admin to delete an EPerson");
         }
+        // Get all workflow-related groups that the current EPerson belongs to
         Set<Group> workFlowGroups = getAllWorkFlowGroups(context, ePerson);
         for (Group group: workFlowGroups) {
-            List<EPerson> ePeople = groupService.allMembers(context, group);
-            if (ePeople.size() == 1 && ePeople.contains(ePerson)) {
+            // Get total number of unique EPerson objs who are a member of this group (or subgroup)
+            int totalMembers = groupService.countAllMembers(context, group);
+            // If only one EPerson is a member, then we cannot delete the last member of this group.
+            if (totalMembers == 1) {
                 throw new EmptyWorkflowGroupException(ePerson.getID(), group.getID());
             }
         }
diff --git a/dspace-api/src/main/java/org/dspace/eperson/GroupServiceImpl.java b/dspace-api/src/main/java/org/dspace/eperson/GroupServiceImpl.java
index faf7b2b52a..d5d7ebcec1 100644
--- a/dspace-api/src/main/java/org/dspace/eperson/GroupServiceImpl.java
+++ b/dspace-api/src/main/java/org/dspace/eperson/GroupServiceImpl.java
@@ -179,8 +179,10 @@ public class GroupServiceImpl extends DSpaceObjectServiceImpl<Group> implements
                 for (CollectionRole collectionRole : collectionRoles) {
                     if (StringUtils.equals(collectionRole.getRoleId(), role.getId())
                             && claimedTask.getWorkflowItem().getCollection() == collectionRole.getCollection()) {
-                        List<EPerson> ePeople = allMembers(context, group);
-                        if (ePeople.size() == 1 && ePeople.contains(ePerson)) {
+                        //  Get total number of unique EPerson objs who are a member of this group (or subgroup)
+                        int totalMembers = countAllMembers(context, group);
+                        // If only one EPerson is a member, then we cannot delete the last member of this group.
+                        if (totalMembers == 1) {
                             throw new IllegalStateException(
                                     "Refused to remove user " + ePerson
                                             .getID() + " from workflow group because the group " + group
@@ -191,8 +193,10 @@ public class GroupServiceImpl extends DSpaceObjectServiceImpl<Group> implements
                 }
             }
             if (!poolTasks.isEmpty()) {
-                List<EPerson> ePeople = allMembers(context, group);
-                if (ePeople.size() == 1 && ePeople.contains(ePerson)) {
+                //  Get total number of unique EPerson objs who are a member of this group (or subgroup)
+                int totalMembers = countAllMembers(context, group);
+                // If only one EPerson is a member, then we cannot delete the last member of this group.
+                if (totalMembers == 1) {
                     throw new IllegalStateException(
                             "Refused to remove user " + ePerson
                                     .getID() + " from workflow group because the group " + group
@@ -212,9 +216,10 @@ public class GroupServiceImpl extends DSpaceObjectServiceImpl<Group> implements
         if (!collectionRoles.isEmpty()) {
             List<PoolTask> poolTasks = poolTaskService.findByGroup(context, groupParent);
             if (!poolTasks.isEmpty()) {
-                List<EPerson> parentPeople = allMembers(context, groupParent);
-                List<EPerson> childPeople = allMembers(context, childGroup);
-                if (childPeople.containsAll(parentPeople)) {
+                // Count number of Groups which have this groupParent as a direct parent
+                int totalChildren = countByParent(context, groupParent);
+                // If only one group has this as a parent, we cannot delete the last child group
+                if (totalChildren == 1) {
                     throw new IllegalStateException(
                             "Refused to remove sub group " + childGroup
                                     .getID() + " from workflow group because the group " + groupParent