/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.jena.fuseki.migrate;

import java.util.Collection ;
import java.util.HashMap ;
import java.util.Map ;

public class Registry<K,T>
{
    protected Map<K, T> registry = new HashMap<>() ;
    
    public Registry() {}
    
    public void put(K key, T value) { registry.put(key, value) ; }
    
    public T get(K key) { return registry.get(key) ; }
    
    public boolean isRegistered(K key)  { return registry.containsKey(key) ; }
    public void remove(K key)           { registry.remove(key) ; } 
    public Collection<K> keys()         { return registry.keySet() ; }
    //public Iterator<String> keys() { return registry.keySet().iterator() ; }
    
    public int size()                   { return registry.size() ; }
    public boolean isEmpty()            { return registry.isEmpty() ; }
}

@@ -888,20 +888,16 @@
 va.util.
-Hash
 Map ;%0Aim
@@ -907,24 +907,49 @@
 t java.util.
+concurrent.ConcurrentHash
 Map ;%0A%0Apubli
@@ -1011,16 +1011,26 @@
 y = new 
+Concurrent
 HashMap%3C
@@ -1105,16 +1105,20 @@
 T value)
+    
  %7B regis
@@ -1137,29 +1137,24 @@
  value) ; %7D%0A
-    %0A
     public T
@@ -1164,16 +1164,32 @@
 t(K key)
+                
  %7B retur
@@ -1208,29 +1208,24 @@
 et(key) ; %7D%0A
-    %0A
     public b
@@ -1466,16 +1466,21 @@
 %3E keys()
+     
  %7B retur
@@ -1514,21 +1514,16 @@
 r() ; %7D%0A
-    %0A
     publ

Switch to ConcurrentHashMap