| /* |
| * |
| * 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.cassandra.utils; |
| |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| import com.google.common.annotations.VisibleForTesting; |
| import com.google.common.util.concurrent.RateLimiter; |
| |
| import org.jboss.byteman.rule.Rule; |
| import org.jboss.byteman.rule.helper.Helper; |
| |
| /** |
| * Helper class to apply rate limiting during fault injection testing; |
| * for an example script, see test/resources/byteman/mutation_limiter.btm. |
| */ |
| @VisibleForTesting |
| public class TestRateLimiter extends Helper |
| { |
| private static final AtomicReference<RateLimiter> ref = new AtomicReference<>(); |
| |
| protected TestRateLimiter(Rule rule) |
| { |
| super(rule); |
| } |
| |
| /** |
| * Acquires a single unit at the given rate. If the rate changes between calls, a new rate limiter is created |
| * and the old one is discarded. |
| */ |
| public void acquire(double rate) |
| { |
| RateLimiter limiter = ref.get(); |
| if (limiter == null || limiter.getRate() != rate) |
| { |
| ref.compareAndSet(limiter, RateLimiter.create(rate)); |
| limiter = ref.get(); |
| } |
| limiter.acquire(1); |
| } |
| } |