[FLINK-18720][runtime] Introduce AbstractResourceManagerDriver as com…

…mon base class of resource manager drivers.

flink-runtime/src/main/java/org/apache/flink/runtime/resourcemanager/active/AbstractResourceManagerDriver.java

@@ -0,0 +1,76 @@
+/*
+ * 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.flink.runtime.resourcemanager.active;
+
+import org.apache.flink.configuration.Configuration;
+import org.apache.flink.runtime.clusterframework.types.ResourceIDRetrievable;
+import org.apache.flink.runtime.concurrent.ScheduledExecutor;
+import org.apache.flink.util.Preconditions;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Abstract common base class for implementations of {@link ResourceManagerDriver}.
+ */
+public abstract class AbstractResourceManagerDriver<WorkerType extends ResourceIDRetrievable>
+	implements ResourceManagerDriver<WorkerType> {
+
+	protected final Logger log = LoggerFactory.getLogger(getClass());
+
+	protected final Configuration flinkConfig;
+	protected final Configuration flinkClientConfig;
+
+	private ResourceEventHandler<WorkerType> resourceEventHandler = null;
+	private ScheduledExecutor mainThreadExecutor = null;
+
+	public AbstractResourceManagerDriver(
+			final Configuration flinkConfig,
+			final Configuration flinkClientConfig) {
+		this.flinkConfig = Preconditions.checkNotNull(flinkConfig);
+		this.flinkClientConfig = Preconditions.checkNotNull(flinkClientConfig);
+	}
+
+	protected final ResourceEventHandler<WorkerType> getResourceEventHandler() {
+		Preconditions.checkState(resourceEventHandler != null,
+				"Cannot get resource event handler. Resource manager driver is not initialized.");
+		return resourceEventHandler;
+	}
+
+	protected final ScheduledExecutor getMainThreadExecutor() {
+		Preconditions.checkState(mainThreadExecutor != null,
+				"Cannot get main thread executor. Resource manager driver is not initialized.");
+		return mainThreadExecutor;
+	}
+
+	@Override
+	public final void initialize(
+			ResourceEventHandler<WorkerType> resourceEventHandler,
+			ScheduledExecutor mainThreadExecutor) throws Exception {
+		this.resourceEventHandler = Preconditions.checkNotNull(resourceEventHandler);
+		this.mainThreadExecutor = Preconditions.checkNotNull(mainThreadExecutor);
+
+		initializeInternal();
+	}
+
+	/**
+	 * Initialize the deployment specific components.
+	 */
+	protected abstract void initializeInternal() throws Exception;
+}