add LookupExtractorFactory.destroy() method

processing/src/main/java/io/druid/query/lookup/LookupExtractorFactory.java

@@ -44,13 +44,28 @@ public interface LookupExtractorFactory extends Supplier<LookupExtractor>
 
   /**
    * <p>
-   *   This method will be called to stop the LookupExtractor upon deletion.
+   *   This method will be called to stop the LookupExtractor upon Druid process stop. This would be used, for
+   *   example, to stop any thread pools it might have.
    *   Calling this method multiple times should always return true if successfully closed.
    * </p>
    * @return Returns false if not successfully closed the {@link LookupExtractor} otherwise returns true
    */
   boolean close();
 
+  /**
+   * <p>
+   *   This method will be called to drop the LookupExtractor upon explicit user request to coordinator to drop
+   *   this lookup. In this method user can do additional cleanup (e.g. deleting disk persisted cache) not done simply
+   *   when Druid process was being stopped to be restarted.
+   *   Calling this method multiple times should always return true if successfully destroyed.
+   * </p>
+   * @return Returns false if not successfully destroyed the {@link LookupExtractor} otherwise returns true
+   */
+  default boolean destroy()
+  {
+    return close();
+  }
+
   /**
    * This method is deprecated and is not removed only to allow 0.10.0 to 0.10.1 transition. It is not used
    * on a cluster that is running 0.10.1. It will be removed in a later release.

server/src/main/java/io/druid/query/lookup/LookupReferencesManager.java

@@ -626,8 +626,8 @@ public void handle(Map<String, LookupExtractorFactoryContainer> lookupMap) throw
       LOG.debug("Loaded lookup [%s] with spec [%s].", lookupName, lookupExtractorFactoryContainer);
 
       if (old != null) {
-        if (!old.getLookupExtractorFactory().close()) {
-          throw new ISE("close method returned false for lookup [%s]:[%s]", lookupName, old);
+        if (!old.getLookupExtractorFactory().destroy()) {
+          throw new ISE("destroy method returned false for lookup [%s]:[%s]", lookupName, old);
         }
       }
     }
@@ -659,9 +659,9 @@ public void handle(Map<String, LookupExtractorFactoryContainer> lookupMap)
       if (lookupExtractorFactoryContainer != null) {
         LOG.debug("Removed lookup [%s] with spec [%s].", lookupName, lookupExtractorFactoryContainer);
 
-        if (!lookupExtractorFactoryContainer.getLookupExtractorFactory().close()) {
+        if (!lookupExtractorFactoryContainer.getLookupExtractorFactory().destroy()) {
           throw new ISE(
-              "close method returned false for lookup [%s]:[%s]",
+              "destroy method returned false for lookup [%s]:[%s]",
               lookupName,
               lookupExtractorFactoryContainer
           );

server/src/test/java/io/druid/query/lookup/LookupReferencesManagerTest.java

@@ -156,7 +156,7 @@ public void testAddGetRemove() throws Exception
   {
     LookupExtractorFactory lookupExtractorFactory = EasyMock.createMock(LookupExtractorFactory.class);
     EasyMock.expect(lookupExtractorFactory.start()).andReturn(true).once();
-    EasyMock.expect(lookupExtractorFactory.close()).andReturn(true).once();
+    EasyMock.expect(lookupExtractorFactory.destroy()).andReturn(true).once();
     EasyMock.replay(lookupExtractorFactory);
 
     Map<String, Object> lookupMap = new HashMap<>();
@@ -221,15 +221,15 @@ public void testCloseIsCalledAfterStopping() throws Exception
   }
 
   @Test
-  public void testCloseIsCalledAfterRemove() throws Exception
+  public void testDestroyIsCalledAfterRemove() throws Exception
   {
     LookupExtractorFactory lookupExtractorFactory = EasyMock.createStrictMock(LookupExtractorFactory.class);
     EasyMock.expect(lookupExtractorFactory.start()).andReturn(true).once();
-    EasyMock.expect(lookupExtractorFactory.close()).andReturn(true).once();
+    EasyMock.expect(lookupExtractorFactory.destroy()).andReturn(true).once();
     EasyMock.replay(lookupExtractorFactory);
 
     Map<String, Object> lookupMap = new HashMap<>();
-    lookupMap.put("testMockForCloseIsCalledAfterRemove", container);
+    lookupMap.put("testMockForDestroyIsCalledAfterRemove", container);
     String strResult = mapper.writeValueAsString(lookupMap);
     Request request = new Request(HttpMethod.GET, new URL("http://localhost:1234/xx"));
     expect(config.getLookupTier()).andReturn(LOOKUP_TIER);
@@ -280,7 +280,7 @@ public void testUpdateWithHigherVersion() throws Exception
   {
     LookupExtractorFactory lookupExtractorFactory1 = EasyMock.createNiceMock(LookupExtractorFactory.class);
     EasyMock.expect(lookupExtractorFactory1.start()).andReturn(true).once();
-    EasyMock.expect(lookupExtractorFactory1.close()).andReturn(true).once();
+    EasyMock.expect(lookupExtractorFactory1.destroy()).andReturn(true).once();
 
     LookupExtractorFactory lookupExtractorFactory2 = EasyMock.createNiceMock(LookupExtractorFactory.class);
     EasyMock.expect(lookupExtractorFactory2.start()).andReturn(true).once();
@@ -461,7 +461,7 @@ public void testRealModeWithMainThread() throws Exception
 
     LookupExtractorFactory lookupExtractorFactory = EasyMock.createMock(LookupExtractorFactory.class);
     EasyMock.expect(lookupExtractorFactory.start()).andReturn(true).once();
-    EasyMock.expect(lookupExtractorFactory.close()).andReturn(true).once();
+    EasyMock.expect(lookupExtractorFactory.destroy()).andReturn(true).once();
     EasyMock.replay(lookupExtractorFactory);
     Assert.assertNull(lookupReferencesManager.get("test"));