org.opensearch.nio.RoundRobinSupplier Maven / Gradle / Ivy
/*
* SPDX-License-Identifier: Apache-2.0
*
* The OpenSearch Contributors require contributions made to
* this file be licensed under the Apache-2.0 license or a
* compatible open source license.
*/
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.
*/
/*
* Modifications Copyright OpenSearch Contributors. See
* GitHub history for details.
*/
package org.opensearch.nio;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Supplier;
final class RoundRobinSupplier implements Supplier {
private final AtomicBoolean selectorsSet = new AtomicBoolean(false);
private volatile S[] selectors;
private AtomicInteger counter = new AtomicInteger(0);
RoundRobinSupplier() {
this.selectors = null;
}
RoundRobinSupplier(S[] selectors) {
this.selectors = selectors;
this.selectorsSet.set(true);
}
@Override
public S get() {
S[] selectors = this.selectors;
return selectors[counter.getAndIncrement() % selectors.length];
}
void setSelectors(S[] selectors) {
if (selectorsSet.compareAndSet(false, true)) {
this.selectors = selectors;
} else {
throw new AssertionError("Selectors already set. Should only be set once.");
}
}
int count() {
return selectors.length;
}
}