Github user Graeme-Miller commented on a diff in the pull request:
https://github.com/apache/brooklyn-server/pull/832#discussion_r139903337
--- Diff:
core/src/main/java/org/apache/brooklyn/core/mgmt/internal/ManagementNodeStateListenerManager.java
---
@@ -0,0 +1,175 @@
+/*
+ * 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.brooklyn.core.mgmt.internal;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.apache.brooklyn.api.mgmt.ha.ManagementNodeState;
+import org.apache.brooklyn.core.mgmt.ManagementContextInjectable;
+import org.apache.brooklyn.core.mgmt.usage.ManagementNodeStateListener;
+import org.apache.brooklyn.core.server.BrooklynServerConfig;
+import org.apache.brooklyn.util.core.ClassLoaderUtils;
+import org.apache.brooklyn.util.core.flags.TypeCoercions;
+import org.apache.brooklyn.util.exceptions.Exceptions;
+import org.apache.brooklyn.util.time.Duration;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.base.Function;
+import com.google.common.collect.Lists;
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.ListenableFuture;
+import com.google.common.util.concurrent.ListeningExecutorService;
+import com.google.common.util.concurrent.MoreExecutors;
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
+
+/**
+ * Handles the notification of {@link ManagementNodeStateListener}s.
+ *
+ * @see {@link BrooklynServerConfig#MANAGEMENT_NODE_STATE_LISTENERS} for
configuring this.
+ * @see {@link
org.apache.brooklyn.core.mgmt.ha.HighAvailabilityManagerImpl#HighAvailabilityManagerImpl(ManagementContextInternal,
ManagementNodeStateListener)}
+ * for how we get notified of the state-change.
+ */
+public class ManagementNodeStateListenerManager implements
ManagementNodeStateListener {
+
+ private static final Logger LOG =
LoggerFactory.getLogger(ManagementNodeStateListenerManager.class);
+
+ private final ManagementContextInternal mgmt;
+
+ private final Object mutex = new Object();
+
+ private final List<ManagementNodeStateListener> listeners =
Lists.newCopyOnWriteArrayList();
+ private ManagementNodeState lastPublishedVal;
+
+ private final AtomicInteger listenerQueueSize = new AtomicInteger();
+
+ private ListeningExecutorService listenerExecutor =
MoreExecutors.listeningDecorator(Executors.newSingleThreadExecutor(new
ThreadFactoryBuilder()
+ .setNameFormat("brooklyn-managementnodestate-listener-%d")
+ .build()));
+
+ public ManagementNodeStateListenerManager(ManagementContextInternal
managementContext) {
+ this.mgmt = checkNotNull(managementContext, "managementContext");
+
+ // Register a coercion from String->ManagementNodeStateListener,
so that MANAGEMENT_NODE_STATE_LISTENERS defined in brooklyn.cfg
+ // will be instantiated, given their class names.
+
TypeCoercions.BrooklynCommonAdaptorTypeCoercions.registerInstanceForClassnameAdapter(
+ new ClassLoaderUtils(this.getClass(), managementContext),
+ ManagementNodeStateListener.class);
+
+ // Although changing listeners to
Collection<ManagementNodeStateListener> is valid at compile time
+ // the collection will contain any objects that could not be
coerced by the function
+ // declared above. Generally this means any string declared in
brooklyn.properties
+ // that is not a ManagementNodeStateListener.
+ Collection<?> rawListeners =
managementContext.getBrooklynProperties().getConfig(BrooklynServerConfig.MANAGEMENT_NODE_STATE_LISTENERS);
+ if (rawListeners != null) {
+ for (Object obj : rawListeners) {
+ if (obj == null) {
+ throw new NullPointerException("null listener in
config " + BrooklynServerConfig.MANAGEMENT_NODE_STATE_LISTENERS);
+ } else if (!(obj instanceof ManagementNodeStateListener)) {
+ throw new ClassCastException("Configured object is not
a "+ManagementNodeStateListener.class.getSimpleName()+". This probably means
coercion failed: " + obj);
+ } else {
+ ManagementNodeStateListener listener =
(ManagementNodeStateListener) obj;
+ if (listener instanceof ManagementContextInjectable) {
+ ((ManagementContextInjectable)
listener).setManagementContext(managementContext);
+ }
+ listeners.add((ManagementNodeStateListener)listener);
+ }
+ }
+ }
+ }
+
+ @Override
+ public void onStateChange(ManagementNodeState state) {
--- End diff --
not sure, but I think it is fine as it is. Your call.
---
