/*
* Copyright DataStax, Inc.
*
* Licensed 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.loadbalancing.nodeset;
import com.datastax.oss.driver.api.core.metadata.Node;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
import java.util.Collections;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.atomic.AtomicBoolean;
import net.jcip.annotations.ThreadSafe;
@ThreadSafe
public class MultiDcNodeSet implements NodeSet {
private static final String UNKNOWN_DC = "";
private final Map<String, Set<Node>> nodes = new ConcurrentHashMap<>();
@Override
public boolean add(@NonNull Node node) {
AtomicBoolean added = new AtomicBoolean();
nodes.compute(
getMapKey(node),
(key, current) -> {
if (current == null) {
// We use CopyOnWriteArraySet because we need
// 1) to preserve insertion order, and
// 2) a "snapshot"-style toArray() implementation
current = new CopyOnWriteArraySet<>();
}
if (current.add(node)) {
added.set(true);
}
return current;
});
return added.get();
}
@Override
public boolean remove(@NonNull Node node) {
AtomicBoolean removed = new AtomicBoolean();
nodes.compute(
getMapKey(node),
(key, current) -> {
if (current != null) {
if (current.remove(node)) {
removed.set(true);
}
}
return current;
});
return removed.get();
}
@Override
@NonNull
public Set<Node> dc(@Nullable String dc) {
return nodes.getOrDefault(getMapKey(dc), Collections.emptySet());
}
@Override
public Set<String> dcs() {
return nodes.keySet();
}
@NonNull
private String getMapKey(@NonNull Node node) {
return getMapKey(node.getDatacenter());
}
@NonNull
private String getMapKey(@Nullable String dc) {
return dc == null ? UNKNOWN_DC : dc;
}
}