Add GenericKeyedObjectPool.getKeys().

src/changes/changes.xml

@@ -61,6 +61,9 @@ The <action> type attribute can be add,update,fix,remove.
     <action dev="ggregory" type="add" due-to="Gary Gregory">
       Add PooledObject.getFullDuration().
     </action>
+    <action dev="ggregory" type="add" due-to="Vamsi Pavan Kumar Sanka, Phil Steitz, Gary Gregory">
+      Add GenericKeyedObjectPool.getKeys().
+    </action>
     <!-- UPDATE -->
     <action dev="ggregory" type="update" due-to="Dependabot">
       Bump actions/checkout from 2.3.4 to 3 #109, #112, #134.

src/main/java/org/apache/commons/pool2/impl/GenericKeyedObjectPool.java

@@ -221,7 +221,7 @@ public String toString() {
      * to ensure any changes to the list of current keys is made in a
      * thread-safe manner.
      */
-    private final List<K> poolKeyList = new ArrayList<>(); // @GuardedBy("keyLock")
+    private final ArrayList<K> poolKeyList = new ArrayList<>(); // @GuardedBy("keyLock")
 
     private final ReadWriteLock keyLock = new ReentrantReadWriteLock(true);
 
@@ -1106,6 +1106,17 @@ public KeyedPooledObjectFactory<K, T> getFactory() {
         return factory;
     }
 
+    /**
+     * Gets a copy of the pool key list.
+     *
+     * @return a copy of the pool key list.
+     * @since 2.12.0
+     */
+    @SuppressWarnings("unchecked")
+    public List<K> getKeys() {
+        return (List<K>) poolKeyList.clone();
+    }
+
     /**
      * Gets the cap on the number of "idle" instances per key in the pool.
      * If maxIdlePerKey is set too low on heavily loaded systems it is possible
@@ -1201,15 +1212,15 @@ public int getNumIdle() {
         return poolMap.values().stream().mapToInt(e -> e.getIdleObjects().size()).sum();
     }
 
+
+    //--- JMX support ----------------------------------------------------------
+
     @Override
     public int getNumIdle(final K key) {
         final ObjectDeque<T> objectDeque = poolMap.get(key);
         return objectDeque != null ? objectDeque.getIdleObjects().size() : 0;
     }
 
-
-    //--- JMX support ----------------------------------------------------------
-
     /**
      * Calculate the number of objects to test in a run of the idle object
      * evictor.

src/test/java/org/apache/commons/pool2/impl/TestGenericKeyedObjectPool.java

@@ -1649,11 +1649,24 @@ public void testFIFO() throws Exception {
         assertEquals( "key4", gkoPool.borrowObject(key),"new-4");
     }
 
+    @Test
+    @Timeout(value = 60, unit = TimeUnit.SECONDS)
+    public void testGetKeys() throws Exception {
+        gkoPool.addObject("one");
+        assertEquals(1, gkoPool.getKeys().size());
+        gkoPool.addObject("two");
+        assertEquals(2, gkoPool.getKeys().size());
+        gkoPool.clear("one");
+        assertEquals(1, gkoPool.getKeys().size());
+        assertEquals("two", (String) gkoPool.getKeys().get(0));
+        gkoPool.clear();
+    }
+
     @Test
     public void testGetStatsString() {
         assertNotNull((gkoPool.getStatsString()));
     }
-
+    
     /**
      * Verify that threads waiting on a depleted pool get served when a checked out object is
      * invalidated.
@@ -1685,7 +1698,7 @@ public void testInvalidateFreesCapacity() throws Exception {
             }
         }
     }
-
+    
     @Test
     public void testInvalidateFreesCapacityForOtherKeys() throws Exception {
         gkoPool.setMaxTotal(1);