KEYCLOAK-14220 Complement methods for accessing clients with Stream variants

model/infinispan/src/main/java/org/keycloak/models/cache/infinispan/ClientAdapter.java

@@ -612,18 +612,18 @@ public class ClientAdapter implements ClientModel, CachedObject {
     }
 
     @Override
-    public Set<RoleModel> getRoles() {
+    public Stream<RoleModel> getRolesStream() {
-        return cacheSession.getClientRoles(cachedRealm, this);
+        return cacheSession.getClientRolesStream(cachedRealm, this);
     }
     
     @Override
-    public Set<RoleModel> getRoles(Integer first, Integer max) {
+    public Stream<RoleModel> getRolesStream(Integer first, Integer max) {
-        return cacheSession.getClientRoles(cachedRealm, this, first, max);
+        return cacheSession.getClientRolesStream(cachedRealm, this, first, max);
     }
     
     @Override
-    public Set<RoleModel> searchForRoles(String search, Integer first, Integer max) {
+    public Stream<RoleModel> searchForRolesStream(String search, Integer first, Integer max) {
-        return cacheSession.searchForClientRoles(cachedRealm, this, search, first, max);
+        return cacheSession.searchForClientRolesStream(cachedRealm, this, search, first, max);
     }
 
     @Override

model/infinispan/src/main/java/org/keycloak/models/cache/infinispan/RealmAdapter.java

@@ -29,6 +29,7 @@ import org.keycloak.storage.client.ClientStorageProvider;
 
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.stream.Stream;
 
 /**
  * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
@@ -755,13 +756,13 @@ public class RealmAdapter implements CachedRealmModel {
     }
 
     @Override
-    public List<ClientModel> getClients() {
+    public Stream<ClientModel> getClientsStream() {
-        return cacheSession.getClients(this);
+        return cacheSession.getClientsStream(this);
     }
 
     @Override
-    public List<ClientModel> getAlwaysDisplayInConsoleClients() {
+    public Stream<ClientModel> getAlwaysDisplayInConsoleClientsStream() {
-        return cacheSession.getAlwaysDisplayInConsoleClients(this);
+        return cacheSession.getAlwaysDisplayInConsoleClientsStream(this);
     }
 
     @Override
@@ -791,13 +792,13 @@ public class RealmAdapter implements CachedRealmModel {
     }
 
     @Override
-    public List<ClientModel> searchClientByClientId(String clientId, Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> searchClientByClientIdStream(String clientId, Integer firstResult, Integer maxResults) {
-        return cacheSession.searchClientsByClientId(this, clientId, firstResult, maxResults);
+        return cacheSession.searchClientsByClientIdStream(this, clientId, firstResult, maxResults);
     }
 
     @Override
-    public List<ClientModel> getClients(Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> getClientsStream(Integer firstResult, Integer maxResults) {
-        return cacheSession.getClients(this, firstResult, maxResults);
+        return cacheSession.getClientsStream(this, firstResult, maxResults);
     }
 
     @Override
@@ -1022,18 +1023,18 @@ public class RealmAdapter implements CachedRealmModel {
     }
 
     @Override
-    public Set<RoleModel> getRoles() {
+    public Stream<RoleModel> getRolesStream() {
-        return cacheSession.getRealmRoles(this);
+        return cacheSession.getRealmRolesStream(this);
     }
     
     @Override
-    public Set<RoleModel> getRoles(Integer first, Integer max) {
+    public Stream<RoleModel> getRolesStream(Integer first, Integer max) {
-        return cacheSession.getRealmRoles(this, first, max);
+        return cacheSession.getRealmRolesStream(this, first, max);
     }
 
     @Override
-    public Set<RoleModel> searchForRoles(String search, Integer first, Integer max) {
+    public Stream<RoleModel> searchForRolesStream(String search, Integer first, Integer max) {
-        return cacheSession.searchForRoles(this, search, first, max);
+        return cacheSession.searchForRolesStream(this, search, first, max);
     }
     
     @Override

model/infinispan/src/main/java/org/keycloak/models/cache/infinispan/RealmCacheSession.java

@@ -31,6 +31,8 @@ import org.keycloak.storage.StorageId;
 import org.keycloak.storage.client.ClientStorageProviderModel;
 
 import java.util.*;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 
 /**
@@ -538,18 +540,18 @@ public class RealmCacheSession implements CacheRealmProvider {
     }
 
     @Override
-    public List<ClientModel> getClients(RealmModel realm, Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> getClientsStream(RealmModel realm, Integer firstResult, Integer maxResults) {
-        return getClientDelegate().getClients(realm, firstResult, maxResults);
+        return getClientDelegate().getClientsStream(realm, firstResult, maxResults);
     }
 
     @Override
-    public List<ClientModel> getClients(RealmModel realm) {
+    public Stream<ClientModel> getClientsStream(RealmModel realm) {
-        return getClientDelegate().getClients(realm);
+        return getClientDelegate().getClientsStream(realm);
     }
 
     @Override
-    public List<ClientModel> getAlwaysDisplayInConsoleClients(RealmModel realm) {
+    public Stream<ClientModel> getAlwaysDisplayInConsoleClientsStream(RealmModel realm) {
-        return getClientDelegate().getAlwaysDisplayInConsoleClients(realm);
+        return getClientDelegate().getAlwaysDisplayInConsoleClientsStream(realm);
     }
 
     @Override
@@ -604,11 +606,11 @@ public class RealmCacheSession implements CacheRealmProvider {
     }
 
     @Override
-    public Set<RoleModel> getRealmRoles(RealmModel realm) {
+    public Stream<RoleModel> getRealmRolesStream(RealmModel realm) {
         String cacheKey = getRolesCacheKey(realm.getId());
         boolean queryDB = invalidations.contains(cacheKey) || listInvalidations.contains(realm.getId());
         if (queryDB) {
-            return getRealmDelegate().getRealmRoles(realm);
+            return getRealmDelegate().getRealmRolesStream(realm);
         }
 
         RoleListQuery query = cache.get(cacheKey, RoleListQuery.class);
@@ -618,33 +620,33 @@ public class RealmCacheSession implements CacheRealmProvider {
 
         if (query == null) {
             Long loaded = cache.getCurrentRevision(cacheKey);
+            // intentionally using deprecated method here because role ids needs to be collected for cashing while the stream returned
             Set<RoleModel> model = getRealmDelegate().getRealmRoles(realm);
             if (model == null) return null;
-            Set<String> ids = new HashSet<>();
+            Set<String> ids = model.stream().map(RoleModel::getId).collect(Collectors.toSet());
-            for (RoleModel role : model) ids.add(role.getId());
             query = new RoleListQuery(loaded, cacheKey, realm, ids);
             logger.tracev("adding realm roles cache miss: realm {0} key {1}", realm.getName(), cacheKey);
             cache.addRevisioned(query, startupRevision);
-            return model;
+            return model.stream();
         }
         Set<RoleModel> list = new HashSet<>();
         for (String id : query.getRoles()) {
             RoleModel role = session.realms().getRoleById(id, realm);
             if (role == null) {
                 invalidations.add(cacheKey);
-                return getRealmDelegate().getRealmRoles(realm);
+                return getRealmDelegate().getRealmRolesStream(realm);
             }
             list.add(role);
         }
-        return list;
+        return list.stream();
     }
 
     @Override
-    public Set<RoleModel> getClientRoles(RealmModel realm, ClientModel client) {
+    public Stream<RoleModel> getClientRolesStream(RealmModel realm, ClientModel client) {
         String cacheKey = getRolesCacheKey(client.getId());
         boolean queryDB = invalidations.contains(cacheKey) || listInvalidations.contains(client.getId()) || listInvalidations.contains(realm.getId());
         if (queryDB) {
-            return getRealmDelegate().getClientRoles(realm, client);
+            return getRealmDelegate().getClientRolesStream(realm, client, null, null);
         }
 
         RoleListQuery query = cache.get(cacheKey, RoleListQuery.class);
@@ -654,46 +656,46 @@ public class RealmCacheSession implements CacheRealmProvider {
 
         if (query == null) {
             Long loaded = cache.getCurrentRevision(cacheKey);
-            Set<RoleModel> model = getRealmDelegate().getClientRoles(realm, client);
+            // intentionally using deprecated method here because role ids needs to be collected for cashing while the stream returned
+            Set<RoleModel> model = getRealmDelegate().getClientRoles(realm, client, null, null);
             if (model == null) return null;
-            Set<String> ids = new HashSet<>();
+            Set<String> ids = model.stream().map(RoleModel::getId).collect(Collectors.toSet());
-            for (RoleModel role : model) ids.add(role.getId());
             query = new RoleListQuery(loaded, cacheKey, realm, ids, client.getClientId());
             logger.tracev("adding client roles cache miss: client {0} key {1}", client.getClientId(), cacheKey);
             cache.addRevisioned(query, startupRevision);
-            return model;
+            return model.stream();
         }
         Set<RoleModel> list = new HashSet<>();
         for (String id : query.getRoles()) {
             RoleModel role = session.realms().getRoleById(id, realm);
             if (role == null) {
                 invalidations.add(cacheKey);
-                return getRealmDelegate().getClientRoles(realm, client);
+                return getRealmDelegate().getClientRolesStream(realm, client, null, null);
             }
             list.add(role);
         }
-        return list;
+        return list.stream();
     }
     
     @Override
-    public Set<RoleModel> getRealmRoles(RealmModel realm, Integer first, Integer max) {
+    public Stream<RoleModel> getRealmRolesStream(RealmModel realm, Integer first, Integer max) {
-        return getRealmDelegate().getRealmRoles(realm, first, max);
+        return getRealmDelegate().getRealmRolesStream(realm, first, max);
     }
 
     @Override
-    public Set<RoleModel> getClientRoles(RealmModel realm, ClientModel client, Integer first, Integer max) {
+    public Stream<RoleModel> getClientRolesStream(RealmModel realm, ClientModel client, Integer first, Integer max) {
-        return getRealmDelegate().getClientRoles(realm, client, first, max);
+        return getRealmDelegate().getClientRolesStream(realm, client, first, max);
     }
     
     @Override
-    public Set<RoleModel> searchForClientRoles(RealmModel realm, ClientModel client, String search, Integer first,
+    public Stream<RoleModel> searchForClientRolesStream(RealmModel realm, ClientModel client, String search, Integer first,
             Integer max) {
-        return getRealmDelegate().searchForClientRoles(realm, client, search, first, max);
+        return getRealmDelegate().searchForClientRolesStream(realm, client, search, first, max);
     }
 
     @Override
-    public Set<RoleModel> searchForRoles(RealmModel realm, String search, Integer first, Integer max) {
+    public Stream<RoleModel> searchForRolesStream(RealmModel realm, String search, Integer first, Integer max) {
-        return getRealmDelegate().searchForRoles(realm, search, first, max);
+        return getRealmDelegate().searchForRolesStream(realm, search, first, max);
     }
 
     @Override
@@ -1128,8 +1130,8 @@ public class RealmCacheSession implements CacheRealmProvider {
     }
 
     @Override
-    public List<ClientModel> searchClientsByClientId(RealmModel realm, String clientId, Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> searchClientsByClientIdStream(RealmModel realm, String clientId, Integer firstResult, Integer maxResults) {
-        return getClientDelegate().searchClientsByClientId(realm, clientId, firstResult, maxResults);
+        return getClientDelegate().searchClientsByClientIdStream(realm, clientId, firstResult, maxResults);
     }
 
     @Override

model/jpa/src/main/java/org/keycloak/models/jpa/ClientAdapter.java

@@ -671,18 +671,18 @@ public class ClientAdapter implements ClientModel, JpaModel<ClientEntity> {
     }
 
     @Override
-    public Set<RoleModel> getRoles() {
+    public Stream<RoleModel> getRolesStream() {
-        return session.realms().getClientRoles(realm, this);
+        return session.realms().getClientRolesStream(realm, this, null, null);
     }
 
     @Override
-    public Set<RoleModel> getRoles(Integer first, Integer max) {
+    public Stream<RoleModel> getRolesStream(Integer first, Integer max) {
-        return session.realms().getClientRoles(realm, this, first, max);
+        return session.realms().getClientRolesStream(realm, this, first, max);
     }
 
     @Override
-    public Set<RoleModel> searchForRoles(String search, Integer first, Integer max) {
+    public Stream<RoleModel> searchForRolesStream(String search, Integer first, Integer max) {
-        return session.realms().searchForClientRoles(realm, this, search, first, max);
+        return session.realms().searchForClientRolesStream(realm, this, search, first, max);
     }
 
     @Override

model/jpa/src/main/java/org/keycloak/models/jpa/JpaRealmProvider.java

@@ -46,6 +46,8 @@ import javax.persistence.TypedQuery;
 
 import java.util.*;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
 import org.keycloak.models.ModelException;
 import static org.keycloak.common.util.StackUtil.getShortStackTrace;
 
@@ -253,17 +255,12 @@ public class JpaRealmProvider implements RealmProvider, ClientProvider {
     }
 
     @Override
-    public Set<RoleModel> getRealmRoles(RealmModel realm) {
+    public Stream<RoleModel> getRealmRolesStream(RealmModel realm) {
         TypedQuery<String> query = em.createNamedQuery("getRealmRoleIds", String.class);
         query.setParameter("realm", realm.getId());
-        List<String> roles = query.getResultList();
+        Stream<String> roles = query.getResultStream();
 
-        if (roles.isEmpty()) return Collections.EMPTY_SET;
+        return roles.map(realm::getRoleById);
-        Set<RoleModel> list = new HashSet<>();
-        for (String id : roles) {
-            list.add(session.realms().getRoleById(id, realm));
-        }
-        return Collections.unmodifiableSet(list);
     }
 
     @Override
@@ -276,65 +273,49 @@ public class JpaRealmProvider implements RealmProvider, ClientProvider {
         return session.realms().getRoleById(roles.get(0), realm);
     }
     
-
     @Override
-    public Set<RoleModel> getClientRoles(RealmModel realm, ClientModel client) {
+    public Stream<RoleModel> getRealmRolesStream(RealmModel realm, Integer first, Integer max) {
-        Set<RoleModel> list = new HashSet<>();
-        TypedQuery<String> query = em.createNamedQuery("getClientRoleIds", String.class);
-        query.setParameter("client", client.getId());
-        List<String> roles = query.getResultList();
-        for (String id : roles) {
-            list.add(session.realms().getRoleById(id, realm));
-        }
-        return list;
-    }
-    
-    @Override
-    public Set<RoleModel> getRealmRoles(RealmModel realm, Integer first, Integer max) {
         TypedQuery<RoleEntity> query = em.createNamedQuery("getRealmRoles", RoleEntity.class);
         query.setParameter("realm", realm.getId());
         
-        return getRoles(query, realm, first, max);
+        return getRolesStream(query, realm, first, max);
     }
 
     @Override
-    public Set<RoleModel> getClientRoles(RealmModel realm, ClientModel client, Integer first, Integer max) {
+    public Stream<RoleModel> getClientRolesStream(RealmModel realm, ClientModel client, Integer first, Integer max) {
         TypedQuery<RoleEntity> query = em.createNamedQuery("getClientRoles", RoleEntity.class);
         query.setParameter("client", client.getId());
         
-        return getRoles(query, realm, first, max);
+        return getRolesStream(query, realm, first, max);
     }
     
-    protected Set<RoleModel> getRoles(TypedQuery<RoleEntity> query, RealmModel realm, Integer first, Integer max) {
+    protected Stream<RoleModel> getRolesStream(TypedQuery<RoleEntity> query, RealmModel realm, Integer first, Integer max) {
         if(Objects.nonNull(first) && Objects.nonNull(max)
                 && first >= 0 && max >= 0) {
             query= query.setFirstResult(first).setMaxResults(max);
         }
 
-        List<RoleEntity> results = query.getResultList();
+        Stream<RoleEntity> results = query.getResultStream();
 
-        return results.stream()
+        return results.map(role -> new RoleAdapter(session, realm, em, role));
-                .map(role -> new RoleAdapter(session, realm, em, role))
-                .collect(Collectors.collectingAndThen(
-                        Collectors.toCollection(LinkedHashSet::new), Collections::unmodifiableSet));
     }
     
     @Override
-    public Set<RoleModel> searchForClientRoles(RealmModel realm, ClientModel client, String search, Integer first, Integer max) {
+    public Stream<RoleModel> searchForClientRolesStream(RealmModel realm, ClientModel client, String search, Integer first, Integer max) {
         TypedQuery<RoleEntity> query = em.createNamedQuery("searchForClientRoles", RoleEntity.class);
         query.setParameter("client", client.getId());
         return searchForRoles(query, realm, search, first, max);
     }
     
     @Override
-    public Set<RoleModel> searchForRoles(RealmModel realm, String search, Integer first, Integer max) {
+    public Stream<RoleModel> searchForRolesStream(RealmModel realm, String search, Integer first, Integer max) {
         TypedQuery<RoleEntity> query = em.createNamedQuery("searchForRealmRoles", RoleEntity.class);
         query.setParameter("realm", realm.getId());
         
         return searchForRoles(query, realm, search, first, max);
     }
     
-    protected Set<RoleModel> searchForRoles(TypedQuery<RoleEntity> query, RealmModel realm, String search, Integer first, Integer max) {
+    protected Stream<RoleModel> searchForRoles(TypedQuery<RoleEntity> query, RealmModel realm, String search, Integer first, Integer max) {
 
         query.setParameter("search", "%" + search.trim().toLowerCase() + "%");
         if(Objects.nonNull(first) && Objects.nonNull(max)
@@ -342,12 +323,9 @@ public class JpaRealmProvider implements RealmProvider, ClientProvider {
             query= query.setFirstResult(first).setMaxResults(max);
         }
         
-        List<RoleEntity> results = query.getResultList();
+        Stream<RoleEntity> results = query.getResultStream();
         
-        return results.stream()
+        return results.map(role -> new RoleAdapter(session, realm, em, role));
-                .map(role -> new RoleAdapter(session, realm, em, role))
-                .collect(Collectors.collectingAndThen(
-                        Collectors.toSet(), Collections::unmodifiableSet));
     }
 
     @Override
@@ -364,7 +342,7 @@ public class JpaRealmProvider implements RealmProvider, ClientProvider {
         }
         String compositeRoleTable = JpaUtils.getTableNameForNativeQuery("COMPOSITE_ROLE", em);
         em.createNativeQuery("delete from " + compositeRoleTable + " where CHILD_ROLE = :role").setParameter("role", roleEntity).executeUpdate();
-        realm.getClients().forEach(c -> c.deleteScopeMapping(role));
+        realm.getClientsStream().forEach(c -> c.deleteScopeMapping(role));
         em.createNamedQuery("deleteClientScopeRoleMappingByRole").setParameter("role", roleEntity).executeUpdate();
         int val = em.createNamedQuery("deleteGroupRoleMappingsByRole").setParameter("roleId", roleEntity.getId()).executeUpdate();
 
@@ -614,7 +592,12 @@ public class JpaRealmProvider implements RealmProvider, ClientProvider {
     }
 
     @Override
-    public List<ClientModel> getClients(RealmModel realm, Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> getClientsStream(RealmModel realm) {
+        return getClientsStream(realm, null, null);
+    }
+
+    @Override
+    public Stream<ClientModel> getClientsStream(RealmModel realm, Integer firstResult, Integer maxResults) {
         TypedQuery<String> query = em.createNamedQuery("getClientIdsByRealm", String.class);
         if (firstResult != null && firstResult > 0) {
             query.setFirstResult(firstResult);
@@ -623,28 +606,18 @@ public class JpaRealmProvider implements RealmProvider, ClientProvider {
             query.setMaxResults(maxResults);
         }
         query.setParameter("realm", realm.getId());
-        List<String> clients = query.getResultList();
+        Stream<String> clients = query.getResultStream();
-        if (clients.isEmpty()) return Collections.EMPTY_LIST;
+
-        List<ClientModel> list = new LinkedList<>();
+        return clients.map(c -> session.clients().getClientById(realm, c)).filter(Objects::nonNull);
-        for (String id : clients) {
-            ClientModel client = session.clients().getClientById(realm, id);
-            if (client != null) list.add(client);
-        }
-        return Collections.unmodifiableList(list);
     }
 
     @Override
-    public List<ClientModel> getAlwaysDisplayInConsoleClients(RealmModel realm) {
+    public Stream<ClientModel> getAlwaysDisplayInConsoleClientsStream(RealmModel realm) {
         TypedQuery<String> query = em.createNamedQuery("getAlwaysDisplayInConsoleClients", String.class);
         query.setParameter("realm", realm.getId());
-        List<String> clients = query.getResultList();
+        Stream<String> clientStream = query.getResultStream();
-        if (clients.isEmpty()) return Collections.EMPTY_LIST;
+
-        List<ClientModel> list = new LinkedList<>();
+        return clientStream.map(c -> session.clients().getClientById(realm, c)).filter(Objects::nonNull);
-        for (String id : clients) {
-            ClientModel client = session.clients().getClientById(realm, id);
-            if (client != null) list.add(client);
-        }
-        return Collections.unmodifiableList(list);
     }
 
     @Override
@@ -673,7 +646,7 @@ public class JpaRealmProvider implements RealmProvider, ClientProvider {
     }
 
     @Override
-    public List<ClientModel> searchClientsByClientId(RealmModel realm, String clientId, Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> searchClientsByClientIdStream(RealmModel realm, String clientId, Integer firstResult, Integer maxResults) {
         TypedQuery<String> query = em.createNamedQuery("searchClientsByClientId", String.class);
         if (firstResult != null && firstResult > 0) {
             query.setFirstResult(firstResult);
@@ -683,9 +656,8 @@ public class JpaRealmProvider implements RealmProvider, ClientProvider {
         }
         query.setParameter("clientId", clientId);
         query.setParameter("realm", realm.getId());
-        List<String> results = query.getResultList();
+        Stream<String> results = query.getResultStream();
-        if (results.isEmpty()) return Collections.EMPTY_LIST;
+        return results.map(c -> session.clients().getClientById(realm, c));
-        return results.stream().map(id -> session.clients().getClientById(realm, id)).collect(Collectors.toList());
     }
 
     @Override

model/jpa/src/main/java/org/keycloak/models/jpa/RealmAdapter.java

@@ -34,6 +34,7 @@ import javax.persistence.TypedQuery;
 import java.util.*;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import static java.util.Objects.nonNull;
 
@@ -829,18 +830,18 @@ public class RealmAdapter implements RealmModel, JpaModel<RealmEntity> {
 
     }
     @Override
-    public List<ClientModel> getClients() {
+    public Stream<ClientModel> getClientsStream() {
-        return session.clients().getClients(this);
+        return session.clients().getClientsStream(this);
     }
 
     @Override
-    public List<ClientModel> getClients(Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> getClientsStream(Integer firstResult, Integer maxResults) {
-        return session.clients().getClients(this, firstResult, maxResults);
+        return session.clients().getClientsStream(this, firstResult, maxResults);
     }
 
     @Override
-    public List<ClientModel> getAlwaysDisplayInConsoleClients() {
+    public Stream<ClientModel> getAlwaysDisplayInConsoleClientsStream() {
-        return session.clients().getAlwaysDisplayInConsoleClients(this);
+        return session.clients().getAlwaysDisplayInConsoleClientsStream(this);
     }
 
     @Override
@@ -872,8 +873,8 @@ public class RealmAdapter implements RealmModel, JpaModel<RealmEntity> {
     }
 
     @Override
-    public List<ClientModel> searchClientByClientId(String clientId, Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> searchClientByClientIdStream(String clientId, Integer firstResult, Integer maxResults) {
-        return session.clients().searchClientsByClientId(this, clientId, firstResult, maxResults);
+        return session.clients().searchClientsByClientIdStream(this, clientId, firstResult, maxResults);
     }
 
     private static final String BROWSER_HEADER_PREFIX = "_browser_header.";
@@ -933,18 +934,18 @@ public class RealmAdapter implements RealmModel, JpaModel<RealmEntity> {
     }
 
     @Override
-    public Set<RoleModel> getRoles() {
+    public Stream<RoleModel> getRolesStream() {
-        return session.realms().getRealmRoles(this);
+        return session.realms().getRealmRolesStream(this);
     }
     
     @Override
-    public Set<RoleModel> getRoles(Integer first, Integer max) {
+    public Stream<RoleModel> getRolesStream(Integer first, Integer max) {
-        return session.realms().getRealmRoles(this, first, max);
+        return session.realms().getRealmRolesStream(this, first, max);
     }
     
     @Override
-    public Set<RoleModel> searchForRoles(String search, Integer first, Integer max) {
+    public Stream<RoleModel> searchForRolesStream(String search, Integer first, Integer max) {
-        return session.realms().searchForRoles(this, search, first, max);
+        return session.realms().searchForRolesStream(this, search, first, max);
     }
 
     @Override

model/map/src/main/java/org/keycloak/models/map/client/AbstractClientModel.java

@@ -25,6 +25,7 @@ import org.keycloak.models.map.common.AbstractEntity;
 import java.util.Objects;
 import java.util.Set;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  *
@@ -81,18 +82,18 @@ public abstract class AbstractClientModel<E extends AbstractEntity> implements C
     }
 
     @Override
-    public Set<RoleModel> getRoles() {
+    public Stream<RoleModel> getRolesStream() {
-        return session.realms().getClientRoles(realm, this);
+        return session.realms().getClientRolesStream(realm, this, null, null);
     }
 
     @Override
-    public Set<RoleModel> getRoles(Integer firstResult, Integer maxResults) {
+    public Stream<RoleModel> getRolesStream(Integer firstResult, Integer maxResults) {
-        return session.realms().getClientRoles(realm, this, firstResult, maxResults);
+        return session.realms().getClientRolesStream(realm, this, firstResult, maxResults);
     }
 
     @Override
-    public Set<RoleModel> searchForRoles(String search, Integer first, Integer max) {
+    public Stream<RoleModel> searchForRolesStream(String search, Integer first, Integer max) {
-        return session.realms().searchForClientRoles(realm, this, search, first, max);
+        return session.realms().searchForClientRolesStream(realm, this, search, first, max);
     }
 
     @Override

model/map/src/main/java/org/keycloak/models/map/client/MapClientProvider.java

@@ -29,9 +29,7 @@ import org.keycloak.models.RealmProvider;
 import org.keycloak.models.RoleModel;
 import org.keycloak.models.map.storage.MapKeycloakTransaction;
 import org.keycloak.models.map.common.Serialization;
-import java.util.Collections;
 import java.util.Comparator;
-import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.UUID;
@@ -134,15 +132,15 @@ public class MapClientProvider implements ClientProvider {
     }
 
     @Override
-    public List<ClientModel> getClients(RealmModel realm, Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> getClientsStream(RealmModel realm, Integer firstResult, Integer maxResults) {
         Stream<ClientModel> s = getClientsStream(realm);
-        if (firstResult >= 0) {
+        if (firstResult != null && firstResult >= 0) {
             s = s.skip(firstResult);
         }
-        if (maxResults >= 0) {
+        if (maxResults != null && maxResults >= 0) {
             s = s.limit(maxResults);
         }
-        return s.collect(Collectors.toList());
+        return s;
     }
 
     private Stream<MapClientEntity> getNotRemovedUpdatedClientsStream() {
@@ -152,7 +150,7 @@ public class MapClientProvider implements ClientProvider {
         return Stream.concat(tx.createdValuesStream(clientStore.keySet()), updatedAndNotRemovedClientsStream);
     }
 
-//    @Override
+    @Override
     public Stream<ClientModel> getClientsStream(RealmModel realm) {
         return getNotRemovedUpdatedClientsStream()
           .filter(entityRealmFilter(realm))
@@ -161,11 +159,6 @@ public class MapClientProvider implements ClientProvider {
         ;
     }
 
-    @Override
-    public List<ClientModel> getClients(RealmModel realm) {
-        return getClientsStream(realm).collect(Collectors.toList());
-    }
-
     @Override
     public ClientModel addClient(RealmModel realm, String id, String clientId) {
         final UUID entityId = id == null ? UUID.randomUUID() : UUID.fromString(id);
@@ -194,10 +187,9 @@ public class MapClientProvider implements ClientProvider {
     }
 
     @Override
-    public List<ClientModel> getAlwaysDisplayInConsoleClients(RealmModel realm) {
+    public Stream<ClientModel> getAlwaysDisplayInConsoleClientsStream(RealmModel realm) {
         return getClientsStream(realm)
-                .filter(ClientModel::isAlwaysDisplayInConsole)
+                .filter(ClientModel::isAlwaysDisplayInConsole);
-                .collect(Collectors.toList());
     }
 
     @Override
@@ -285,9 +277,9 @@ public class MapClientProvider implements ClientProvider {
     }
 
     @Override
-    public List<ClientModel> searchClientsByClientId(RealmModel realm, String clientId, Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> searchClientsByClientIdStream(RealmModel realm, String clientId, Integer firstResult, Integer maxResults) {
         if (clientId == null) {
-            return Collections.EMPTY_LIST;
+            return Stream.empty();
         }
         String clientIdLower = clientId.toLowerCase();
         Stream<MapClientEntity> s = getNotRemovedUpdatedClientsStream()
@@ -295,17 +287,14 @@ public class MapClientProvider implements ClientProvider {
           .filter(entity -> entity.getClientId() != null && entity.getClientId().toLowerCase().contains(clientIdLower))
           .sorted(COMPARE_BY_CLIENT_ID);
 
-        if (firstResult >= 0) {
+        if (firstResult != null && firstResult >= 0) {
             s = s.skip(firstResult);
         }
-        if (maxResults >= 0) {
+        if (maxResults != null && maxResults >= 0) {
             s = s.limit(maxResults);
         }
 
-        return s
+        return s.map(entityToAdapterFunc(realm));
-          .map(entityToAdapterFunc(realm))
-          .collect(Collectors.toList())
-        ;
     }
 
     @Override

server-spi-private/src/main/java/org/keycloak/storage/client/UnsupportedOperationsClientStorageAdapter.java

@@ -22,7 +22,7 @@ import org.keycloak.models.RoleModel;
 
 import java.util.Collections;
 import java.util.List;
-import java.util.Set;
+import java.util.stream.Stream;
 
 /**
  * Base helper class.  Unsupported operations are implemented here that throw exception on invocation.
@@ -52,18 +52,18 @@ public abstract class UnsupportedOperationsClientStorageAdapter implements Clien
     }
 
     @Override
-    public final Set<RoleModel> getRoles() {
+    public final Stream<RoleModel> getRolesStream() {
-        return Collections.EMPTY_SET;
+        return Stream.empty();
     }
     
     @Override
-    public final Set<RoleModel> getRoles(Integer first, Integer max) {
+    public final Stream<RoleModel> getRolesStream(Integer first, Integer max) {
-        return Collections.EMPTY_SET;
+        return Stream.empty();
     }
     
     @Override
-    public final Set<RoleModel> searchForRoles(String search, Integer first, Integer max) {
+    public final Stream<RoleModel> searchForRolesStream(String search, Integer first, Integer max) {
-        return Collections.EMPTY_SET;
+        return Stream.empty();
     }
 
     @Override

server-spi/src/main/java/org/keycloak/models/ClientModel.java

@@ -17,7 +17,6 @@
 
 package org.keycloak.models;
 
-import java.util.List;
 import java.util.Map;
 import java.util.Set;
 

server-spi/src/main/java/org/keycloak/models/ClientProvider.java

@@ -20,6 +20,8 @@ import org.keycloak.provider.Provider;
 import org.keycloak.storage.client.ClientLookupProvider;
 
 import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  * Provider of the client records.
@@ -31,21 +33,46 @@ public interface ClientProvider extends ClientLookupProvider, Provider {
 
     /**
      * Returns the clients of the given realm.
+     * @deprecated use the stream variant instead
      * @param realm Realm.
      * @param firstResult First result to return. Ignored if negative or {@code null}.
-     * @param maxResults Maximim number of results to return. Ignored if negative or {@code null}.
+     * @param maxResults Maximum number of results to return. Ignored if negative or {@code null}.
      * @return List of the clients. Never returns {@code null}.
      */
-    List<ClientModel> getClients(RealmModel realm, Integer firstResult, Integer maxResults);
+    @Deprecated
+    default List<ClientModel> getClients(RealmModel realm, Integer firstResult, Integer maxResults) {
+        return getClientsStream(realm, firstResult, maxResults).collect(Collectors.toList());
+    }
+
+    /**
+     * Returns the clients of the given realm as a stream.
+     * @param realm Realm.
+     * @param firstResult First result to return. Ignored if negative or {@code null}.
+     * @param maxResults Maximum number of results to return. Ignored if negative or {@code null}.
+     * @return Stream of the clients. Never returns {@code null}.
+     */
+    Stream<ClientModel> getClientsStream(RealmModel realm, Integer firstResult, Integer maxResults);
 
     /**
      * Returns all the clients of the given realm.
+     * @deprecated use the stream variant instead
      * Effectively the same as the call {@code getClients(realm, null, null)}.
      * @param realm Realm.
      * @return List of the clients. Never returns {@code null}.
      */
+    @Deprecated
     default List<ClientModel> getClients(RealmModel realm) {
-        return this.getClients(realm, null, null);
+        return this.getClientsStream(realm, null, null).collect(Collectors.toList());
+    }
+
+    /**
+     * Returns all the clients of the given realm as a stream.
+     * Effectively the same as the call {@code getClientsStream(realm, null, null)}.
+     * @param realm Realm.
+     * @return Stream of the clients. Never returns {@code null}.
+     */
+    default Stream<ClientModel> getClientsStream(RealmModel realm) {
+        return this.getClientsStream(realm, null, null);
     }
 
     /**
@@ -81,10 +108,21 @@ public interface ClientProvider extends ClientLookupProvider, Provider {
 
     /**
      * Returns a list of clients that are expected to always show up in account console.
+     * @deprecated use the stream variant instead
      * @param realm Realm owning the clients.
      * @return List of the clients. Never returns {@code null}.
      */
-    List<ClientModel> getAlwaysDisplayInConsoleClients(RealmModel realm);
+    @Deprecated
+    default List<ClientModel> getAlwaysDisplayInConsoleClients(RealmModel realm) {
+        return getAlwaysDisplayInConsoleClientsStream(realm).collect(Collectors.toList());
+    }
+
+    /**
+     * Returns a stream of clients that are expected to always show up in account console.
+     * @param realm Realm owning the clients.
+     * @return Stream of the clients. Never returns {@code null}.
+     */
+    Stream<ClientModel> getAlwaysDisplayInConsoleClientsStream(RealmModel realm);
 
     /**
      * Removes given client from the given realm.

server-spi/src/main/java/org/keycloak/models/RealmModel.java

@@ -26,6 +26,8 @@ import org.keycloak.storage.client.ClientStorageProvider;
 import org.keycloak.storage.client.ClientStorageProviderModel;
 
 import java.util.*;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
@@ -284,11 +286,28 @@ public interface RealmModel extends RoleContainerModel {
 
     void removeDefaultGroup(GroupModel group);
 
-    List<ClientModel> getClients();
+    @Deprecated
-    List<ClientModel> getClients(Integer firstResult, Integer maxResults);
+    default List<ClientModel> getClients() {
+        return getClientsStream(null, null).collect(Collectors.toList());
+    }
+
+    Stream<ClientModel> getClientsStream();
+
+    @Deprecated
+    default List<ClientModel> getClients(Integer firstResult, Integer maxResults) {
+        return getClientsStream(firstResult, maxResults).collect(Collectors.toList());
+    }
+
+    Stream<ClientModel> getClientsStream(Integer firstResult, Integer maxResults);
+
     Long getClientsCount();
 
-    List<ClientModel> getAlwaysDisplayInConsoleClients();
+    @Deprecated
+    default List<ClientModel> getAlwaysDisplayInConsoleClients() {
+        return getAlwaysDisplayInConsoleClientsStream().collect(Collectors.toList());
+    }
+
+    Stream<ClientModel> getAlwaysDisplayInConsoleClientsStream();
 
     ClientModel addClient(String name);
 
@@ -298,7 +317,13 @@ public interface RealmModel extends RoleContainerModel {
 
     ClientModel getClientById(String id);
     ClientModel getClientByClientId(String clientId);
-    List<ClientModel> searchClientByClientId(String clientId, Integer firstResult, Integer maxResults);
+
+    @Deprecated
+    default List<ClientModel> searchClientByClientId(String clientId, Integer firstResult, Integer maxResults) {
+        return searchClientByClientIdStream(clientId, firstResult, maxResults).collect(Collectors.toList());
+    }
+
+    Stream<ClientModel> searchClientByClientIdStream(String clientId, Integer firstResult, Integer maxResults);
     
     void updateRequiredCredentials(Set<String> creds);
 

server-spi/src/main/java/org/keycloak/models/RealmProvider.java

@@ -22,6 +22,8 @@ import org.keycloak.provider.Provider;
 
 import java.util.List;
 import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
@@ -81,16 +83,44 @@ public interface RealmProvider extends Provider /* TODO: Remove in future versio
 
     RoleModel getRealmRole(RealmModel realm, String name);
 
-    Set<RoleModel> getRealmRoles(RealmModel realm);
+    // TODO switch all usages to the stream variant
+    @Deprecated
+    default Set<RoleModel> getRealmRoles(RealmModel realm) {
+        return getRealmRolesStream(realm).collect(Collectors.toSet());
+    }
 
-    Set<RoleModel> getRealmRoles(RealmModel realm, Integer first, Integer max);
+    Stream<RoleModel> getRealmRolesStream(RealmModel realm);
 
-    Set<RoleModel> getClientRoles(RealmModel realm, ClientModel client, Integer first, Integer max);
+    @Deprecated
+    default Set<RoleModel> getRealmRoles(RealmModel realm, Integer first, Integer max) {
+        return getRealmRolesStream(realm, first, max).collect(Collectors.toSet());
+    }
 
-    Set<RoleModel> searchForClientRoles(RealmModel realm, ClientModel client, String search, Integer first,
+    Stream<RoleModel> getRealmRolesStream(RealmModel realm, Integer first, Integer max);
-            Integer max);
 
-    Set<RoleModel> searchForRoles(RealmModel realm, String search, Integer first, Integer max);
+    // TODO switch all usages to the stream variant
+    @Deprecated
+    default Set<RoleModel> getClientRoles(RealmModel realm, ClientModel client, Integer first, Integer max) {
+        return getClientRolesStream(realm, client, first, max).collect(Collectors.toSet());
+    }
+
+    Stream<RoleModel> getClientRolesStream(RealmModel realm, ClientModel client, Integer first, Integer max);
+
+    @Deprecated
+    default Set<RoleModel> searchForClientRoles(RealmModel realm, ClientModel client, String search, Integer first,
+            Integer max) {
+        return searchForClientRolesStream(realm, client, search, first, max).collect(Collectors.toSet());
+    }
+
+    Stream<RoleModel> searchForClientRolesStream(RealmModel realm, ClientModel client, String search, Integer first,
+                                                Integer max);
+
+    @Deprecated
+    default Set<RoleModel> searchForRoles(RealmModel realm, String search, Integer first, Integer max) {
+        return searchForRolesStream(realm, search, first, max).collect(Collectors.toSet());
+    }
+
+    Stream<RoleModel> searchForRolesStream(RealmModel realm, String search, Integer first, Integer max);
 
     boolean removeRole(RealmModel realm, RoleModel role);
 
@@ -114,7 +144,9 @@ public interface RealmProvider extends Provider /* TODO: Remove in future versio
 
     /**
      * TODO: To be @deprecated Use the corresponding method from {@link ??RoleProvider}. */
-    public Set<RoleModel> getClientRoles(RealmModel realm, ClientModel client);
+    default public Stream<RoleModel> getClientRolesStream(RealmModel realm, ClientModel client) {
+        return getClientRolesStream(realm, client, null, null);
+    }
 
     /**
      * TODO: To be @deprecated Use the corresponding method from {@link ??RoleProvider}. */
@@ -151,16 +183,11 @@ public interface RealmProvider extends Provider /* TODO: Remove in future versio
         return this.getClients(realm, null, null);
     }
 
-    /**
-     * @deprecated Use the corresponding method from {@link ClientProvider}. */
-    @Override
-    public List<ClientModel> getClients(RealmModel realm, Integer firstResult, Integer maxResults);
-
     /**
      * @deprecated Use the corresponding method from {@link ClientProvider}. */
     @Override
     default List<ClientModel> searchClientsByClientId(String clientId, Integer firstResult, Integer maxResults, RealmModel realm) {
-        return searchClientsByClientId(realm, clientId, firstResult, maxResults);
+        return searchClientsByClientId(clientId, firstResult, maxResults, realm);
     }
 
     /**
@@ -173,11 +200,6 @@ public interface RealmProvider extends Provider /* TODO: Remove in future versio
     @Override
     default ClientModel getClientById(String id, RealmModel realm) { return getClientById(realm, id); }
 
-    /**
-     * @deprecated Use the corresponding method from {@link ClientProvider}. */
-    @Override
-    public List<ClientModel> searchClientsByClientId(RealmModel realm, String clientId, Integer firstResult, Integer maxResults);
-
     /**
      * @deprecated Use the corresponding method from {@link ClientProvider}. */
     @Override
@@ -196,10 +218,4 @@ public interface RealmProvider extends Provider /* TODO: Remove in future versio
     /**
      * @deprecated Use the corresponding method from {@link ClientProvider}. */
     default boolean removeClient(String id, RealmModel realm) { return this.removeClient(realm, id); }
-
-    /**
-     * @deprecated Use the corresponding method from {@link ClientProvider}. */
-    @Override
-    public List<ClientModel> getAlwaysDisplayInConsoleClients(RealmModel realm);
-
 }

server-spi/src/main/java/org/keycloak/models/RoleContainerModel.java

@@ -25,6 +25,8 @@ import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
@@ -47,11 +49,29 @@ public interface RoleContainerModel {
 
     boolean removeRole(RoleModel role);
 
-    Set<RoleModel> getRoles();
+    // TODO switch all usages to the stream variant
+    @Deprecated
+    default Set<RoleModel> getRoles() {
+        return getRolesStream().collect(Collectors.toSet());
+    }
 
-    Set<RoleModel> getRoles(Integer firstResult, Integer maxResults);
+    Stream<RoleModel> getRolesStream();
 
-    Set<RoleModel> searchForRoles(String search, Integer first, Integer max);
+    // TODO switch all usages to the stream variant
+    @Deprecated
+    default Set<RoleModel> getRoles(Integer firstResult, Integer maxResults) {
+        return getRolesStream(firstResult, maxResults).collect(Collectors.toSet());
+    }
+
+    Stream<RoleModel> getRolesStream(Integer firstResult, Integer maxResults);
+
+    // TODO switch all usages to the stream variant
+    @Deprecated
+    default Set<RoleModel> searchForRoles(String search, Integer first, Integer max) {
+        return searchForRolesStream(search, first, max).collect(Collectors.toSet());
+    }
+
+    Stream<RoleModel> searchForRolesStream(String search, Integer first, Integer max);
 
     List<String> getDefaultRoles();
 

server-spi/src/main/java/org/keycloak/storage/client/ClientLookupProvider.java

@@ -20,6 +20,8 @@ import org.keycloak.models.ClientModel;
 import org.keycloak.models.RealmModel;
 
 import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  * Abstraction interface for lookoup of clients by id and clientId.  These methods required for participating in login flows.
@@ -71,10 +73,14 @@ public interface ClientLookupProvider {
      * @param clientId Searched substring of the public client
      *   identifier ({@code client_id} in OIDC or {@code entityID} in SAML.)
      * @param firstResult First result to return. Ignored if negative or {@code null}.
-     * @param maxResults Maximim number of results to return. Ignored if negative or {@code null}.
+     * @param maxResults Maximum number of results to return. Ignored if negative or {@code null}.
-     * @return Model of the client, or {@code null} if no client is found.
+     * @return List of ClientModel or an empty list if no client is found.
+     * @deprecated Use {@link #searchClientsByClientIdStream(org.keycloak.models.RealmModel, java.lang.String, java.lang.Integer, java.lang.Integer)} instead.
      */
-    List<ClientModel> searchClientsByClientId(RealmModel realm, String clientId, Integer firstResult, Integer maxResults);
+    @Deprecated
+    default List<ClientModel> searchClientsByClientId(String clientId, Integer firstResult, Integer maxResults, RealmModel realm) {
+        return searchClientsByClientIdStream(realm, clientId, firstResult, maxResults).collect(Collectors.toList());
+    }
 
     /**
      * Case-insensitive search for clients that contain the given string in their public client identifier.
@@ -82,11 +88,8 @@ public interface ClientLookupProvider {
      * @param clientId Searched substring of the public client
      *   identifier ({@code client_id} in OIDC or {@code entityID} in SAML.)
      * @param firstResult First result to return. Ignored if negative or {@code null}.
-     * @param maxResults Maximim number of results to return. Ignored if negative or {@code null}.
+     * @param maxResults Maximum number of results to return. Ignored if negative or {@code null}.
-     * @return Models of the matching clients. Never returns {@code null}.
+     * @return Stream of ClientModel or an empty stream if no client is found.
-     * @deprecated Use {@link #searchClientsByClientId(org.keycloak.models.RealmModel, java.lang.String, java.lang.Integer, java.lang.Integer)} instead.
      */
-    default List<ClientModel> searchClientsByClientId(String clientId, Integer firstResult, Integer maxResults, RealmModel realm) {
+    Stream<ClientModel> searchClientsByClientIdStream(RealmModel realm, String clientId, Integer firstResult, Integer maxResults);
-        return searchClientsByClientId(realm, clientId, firstResult, maxResults);
-    }
 }

services/src/main/java/org/keycloak/services/DefaultKeycloakSession.java

@@ -178,7 +178,9 @@ public class DefaultKeycloakSession implements KeycloakSession {
 
     @Override
     public ClientProvider clientStorageManager() {
-        if (clientStorageManager == null) clientStorageManager = new ClientStorageManager(this);
+        if (clientStorageManager == null) {
+            clientStorageManager = new ClientStorageManager(this, factory.getClientStorageProviderTimeout());
+        }
         return clientStorageManager;
     }
 

services/src/main/java/org/keycloak/services/DefaultKeycloakSessionFactory.java

@@ -59,6 +59,12 @@ public class DefaultKeycloakSessionFactory implements KeycloakSessionFactory, Pr
     // TODO: Likely should be changed to int and use Time.currentTime() to be compatible with all our "time" reps
     protected long serverStartupTimestamp;
 
+    /**
+     * Timeout is used as time boundary for obtaining clients from an external client storage. Default value is set
+     * to 3000 milliseconds and it's configurable.
+     */
+    private long clientStorageProviderTimeout;
+
     @Override
     public void register(ProviderEventListener listener) {
         listeners.add(listener);
@@ -79,6 +85,8 @@ public class DefaultKeycloakSessionFactory implements KeycloakSessionFactory, Pr
     public void init() {
         serverStartupTimestamp = System.currentTimeMillis();
 
+        clientStorageProviderTimeout = Config.scope("client").getLong("storageProviderTimeout", 3000L);
+
         ProviderManager pm = new ProviderManager(KeycloakDeploymentInfo.create().services(), getClass().getClassLoader(), Config.scope().getArray("providers"));
         spis.addAll(pm.loadSpis());
         factoriesMap = loadFactories(pm);
@@ -351,6 +359,10 @@ public class DefaultKeycloakSessionFactory implements KeycloakSessionFactory, Pr
         return packageName.startsWith("org.keycloak") && !packageName.startsWith("org.keycloak.examples");
     }
 
+    public long getClientStorageProviderTimeout() {
+        return clientStorageProviderTimeout;
+    }
+
     /**
      * @return timestamp of Keycloak server startup
      */

services/src/main/java/org/keycloak/storage/ClientStorageManager.java

@@ -28,9 +28,11 @@ import org.keycloak.storage.client.ClientLookupProvider;
 import org.keycloak.storage.client.ClientStorageProvider;
 import org.keycloak.storage.client.ClientStorageProviderFactory;
 import org.keycloak.storage.client.ClientStorageProviderModel;
+import org.keycloak.utils.ServicesUtils;
 
 import java.util.LinkedList;
 import java.util.List;
+import java.util.stream.Stream;
 
 /**
  * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
@@ -41,6 +43,8 @@ public class ClientStorageManager implements ClientProvider {
 
     protected KeycloakSession session;
 
+    private long clientStorageProviderTimeout;
+
     public static boolean isStorageProviderEnabled(RealmModel realm, String providerId) {
         ClientStorageProviderModel model = getStorageProviderModel(realm, providerId);
         return model.isEnabled();
@@ -118,8 +122,9 @@ public class ClientStorageManager implements ClientProvider {
     }
 
 
-    public ClientStorageManager(KeycloakSession session) {
+    public ClientStorageManager(KeycloakSession session, long clientStorageProviderTimeout) {
         this.session = session;
+        this.clientStorageProviderTimeout = clientStorageProviderTimeout;
     }
 
     @Override
@@ -147,17 +152,22 @@ public class ClientStorageManager implements ClientProvider {
         return null;
     }
 
+    /**
+     * Obtaining clients from an external client storage is time-bounded. In case the external client storage
+     * isn't available at least clients from a local storage are returned. For this purpose
+     * the {@link org.keycloak.services.DefaultKeycloakSessionFactory#getClientStorageProviderTimeout()} property is used.
+     * Default value is 3000 milliseconds and it's configurable.
+     * See {@link org.keycloak.services.DefaultKeycloakSessionFactory} for details.
+     */
     @Override
-    public List<ClientModel> searchClientsByClientId(RealmModel realm, String clientId, Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> searchClientsByClientIdStream(RealmModel realm, String clientId, Integer firstResult, Integer maxResults) {
-        List<ClientModel> clients = session.clientLocalStorage().searchClientsByClientId(realm, clientId,  firstResult, maxResults);
+        Stream<ClientModel> local = session.clientLocalStorage().searchClientsByClientIdStream(realm, clientId,  firstResult, maxResults);
-        if (clients != null) {
+        Stream<ClientModel> ext = getEnabledStorageProviders(session, realm, ClientLookupProvider.class).stream()
-            return clients;
+                .flatMap(ServicesUtils.timeBound(session,
-        }
+                        clientStorageProviderTimeout,
-        for (ClientLookupProvider provider : getEnabledStorageProviders(session, realm, ClientLookupProvider.class)) {
+                        p -> ((ClientLookupProvider) p).searchClientsByClientIdStream(realm, clientId, firstResult, maxResults)));
-            clients = provider.searchClientsByClientId(realm, clientId, firstResult, maxResults);
+
-            if (clients != null) return clients;
+        return Stream.concat(local, ext);
-        }
-        return null;
     }
 
     @Override
@@ -171,13 +181,13 @@ public class ClientStorageManager implements ClientProvider {
     }
 
     @Override
-    public List<ClientModel> getClients(RealmModel realm, Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> getClientsStream(RealmModel realm, Integer firstResult, Integer maxResults) {
-       return session.clientLocalStorage().getClients(realm, firstResult, maxResults);
+       return session.clientLocalStorage().getClientsStream(realm, firstResult, maxResults);
     }
 
     @Override
-    public List<ClientModel> getClients(RealmModel realm) {
+    public Stream<ClientModel> getClientsStream(RealmModel realm) {
-        return session.clientLocalStorage().getClients(realm);
+        return session.clientLocalStorage().getClientsStream(realm);
     }
 
     @Override
@@ -186,8 +196,8 @@ public class ClientStorageManager implements ClientProvider {
     }
 
     @Override
-    public List<ClientModel> getAlwaysDisplayInConsoleClients(RealmModel realm) {
+    public Stream<ClientModel> getAlwaysDisplayInConsoleClientsStream(RealmModel realm) {
-        return session.clientLocalStorage().getAlwaysDisplayInConsoleClients(realm);
+        return session.clientLocalStorage().getAlwaysDisplayInConsoleClientsStream(realm);
     }
 
     @Override

services/src/main/java/org/keycloak/storage/openshift/OpenshiftClientStorageProvider.java

@@ -26,9 +26,8 @@ import org.keycloak.storage.StorageId;
 import org.keycloak.storage.client.ClientStorageProvider;
 import org.keycloak.storage.client.ClientStorageProviderModel;
 
-import java.util.Collections;
-import java.util.List;
 import java.util.regex.Matcher;
+import java.util.stream.Stream;
 
 /**
  * @author <a href="mailto:psilva@redhat.com">Pedro Igor</a>
@@ -76,9 +75,9 @@ public class OpenshiftClientStorageProvider implements ClientStorageProvider {
     }
 
     @Override
-    public List<ClientModel> searchClientsByClientId(RealmModel realm, String clientId, Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> searchClientsByClientIdStream(RealmModel realm, String clientId, Integer firstResult, Integer maxResults) {
         // TODO not sure about this, but I don't see this implementation using the search now
-        return Collections.singletonList(getClientByClientId(realm, clientId));
+        return Stream.of(getClientByClientId(realm, clientId));
     }
 
     @Override

services/src/main/java/org/keycloak/utils/ServicesUtils.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2020 Red Hat, Inc. and/or its affiliates
+ * and other contributors as indicated by the @author tags.
+ *
+ * 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.
+ */
+
+package org.keycloak.utils;
+
+import org.jboss.logging.Logger;
+import org.keycloak.executors.ExecutorsProvider;
+import org.keycloak.models.KeycloakSession;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.function.Function;
+import java.util.stream.Stream;
+
+/**
+ * Utility class for general helper methods used across the keycloak-services.
+ */
+public class ServicesUtils {
+
+    private static final Logger logger = Logger.getLogger(ServicesUtils.class);
+
+    public static <T, R> Function<? super T,? extends Stream<? extends R>> timeBound(KeycloakSession session,
+                                                                                     long timeout,
+                                                                                     Function<T, ? extends Stream<R>> func) {
+        ExecutorService executor = session.getProvider(ExecutorsProvider.class).getExecutor("storage-provider-threads");
+        return p -> {
+            Callable<? extends Stream<R>> c = () -> func.apply(p);
+            Future<? extends Stream<R>> future = executor.submit(c);
+            try {
+                return future.get(timeout, TimeUnit.MILLISECONDS);
+            } catch (InterruptedException | ExecutionException | TimeoutException e) {
+                future.cancel(true);
+                logger.debug("Function failed to return on time.", e);
+                return Stream.empty();
+            }
+        };
+    }
+}

testsuite/integration-arquillian/servers/auth-server/services/testsuite-providers/src/main/java/org/keycloak/testsuite/federation/HardcodedClientStorageProvider.java

@@ -36,7 +36,6 @@ import java.util.Collections;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
-import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -79,11 +78,11 @@ public class HardcodedClientStorageProvider implements ClientStorageProvider, Cl
     }
 
     @Override
-    public List<ClientModel> searchClientsByClientId(RealmModel realm, String clientId, Integer firstResult, Integer maxResults) {
+    public Stream<ClientModel> searchClientsByClientIdStream(RealmModel realm, String clientId, Integer firstResult, Integer maxResults) {
         if (clientId != null && this.clientId.toLowerCase().contains(clientId.toLowerCase())) {
-            return Collections.singletonList(new ClientAdapter(realm));
+            return Stream.of(new ClientAdapter(realm));
         }
-        return Collections.EMPTY_LIST;
+        return Stream.empty();
     }
 
     public class ClientAdapter extends AbstractReadOnlyClientStorageAdapter {