com.datastax.oss.driver.internal.core.metadata.MultiplexingNodeStateListener Maven / Gradle / Ivy
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* 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 com.datastax.oss.driver.internal.core.metadata;
import com.datastax.oss.driver.api.core.metadata.Node;
import com.datastax.oss.driver.api.core.metadata.NodeStateListener;
import com.datastax.oss.driver.api.core.session.Session;
import com.datastax.oss.driver.internal.core.util.Loggers;
import edu.umd.cs.findbugs.annotations.NonNull;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.function.Consumer;
import net.jcip.annotations.ThreadSafe;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Combines multiple node state listeners into a single one.
*
* Any exception thrown by a child listener is caught and logged.
*/
@ThreadSafe
public class MultiplexingNodeStateListener implements NodeStateListener {
private static final Logger LOG = LoggerFactory.getLogger(MultiplexingNodeStateListener.class);
private final List listeners = new CopyOnWriteArrayList<>();
public MultiplexingNodeStateListener() {}
public MultiplexingNodeStateListener(NodeStateListener... listeners) {
this(Arrays.asList(listeners));
}
public MultiplexingNodeStateListener(Collection listeners) {
addListeners(listeners);
}
private void addListeners(Collection source) {
for (NodeStateListener listener : source) {
addListener(listener);
}
}
private void addListener(NodeStateListener toAdd) {
Objects.requireNonNull(toAdd, "listener cannot be null");
if (toAdd instanceof MultiplexingNodeStateListener) {
addListeners(((MultiplexingNodeStateListener) toAdd).listeners);
} else {
listeners.add(toAdd);
}
}
public void register(@NonNull NodeStateListener listener) {
addListener(listener);
}
@Override
public void onAdd(@NonNull Node node) {
invokeListeners(listener -> listener.onAdd(node), "onAdd");
}
@Override
public void onUp(@NonNull Node node) {
invokeListeners(listener -> listener.onUp(node), "onUp");
}
@Override
public void onDown(@NonNull Node node) {
invokeListeners(listener -> listener.onDown(node), "onDown");
}
@Override
public void onRemove(@NonNull Node node) {
invokeListeners(listener -> listener.onRemove(node), "onRemove");
}
@Override
public void onSessionReady(@NonNull Session session) {
invokeListeners(listener -> listener.onSessionReady(session), "onSessionReady");
}
@Override
public void close() throws Exception {
for (NodeStateListener listener : listeners) {
try {
listener.close();
} catch (Exception e) {
Loggers.warnWithException(
LOG, "Unexpected error while closing node state listener {}.", listener, e);
}
}
}
private void invokeListeners(@NonNull Consumer action, String event) {
for (NodeStateListener listener : listeners) {
try {
action.accept(listener);
} catch (Exception e) {
Loggers.warnWithException(
LOG,
"Unexpected error while notifying node state listener {} of an {} event.",
listener,
event,
e);
}
}
}
}