org.glowroot.central.util.RateLimiter Maven / Gradle / Ivy
/*
* Copyright 2016 the original author or authors.
*
* 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 org.glowroot.central.util;
import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import static java.util.concurrent.TimeUnit.DAYS;
public class RateLimiter {
private static final int NO_MAXIMUM_SIZE = -1;
private final Cache acquiredRecently;
public RateLimiter() {
this(NO_MAXIMUM_SIZE);
}
public RateLimiter(int maximumSize) {
CacheBuilder cache = CacheBuilder.newBuilder()
.expireAfterWrite(1, DAYS);
if (maximumSize != NO_MAXIMUM_SIZE) {
cache.maximumSize(maximumSize);
}
acquiredRecently = cache.build();
}
public boolean tryAcquire(T key) {
synchronized (acquiredRecently) {
if (acquiredRecently.getIfPresent(key) != null) {
return false;
}
acquiredRecently.put(key, true);
return true;
}
}
public void invalidate(T key) {
acquiredRecently.invalidate(key);
}
}