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Diffstat (limited to 'components/slice-analysis-ms/src/main/java/org/onap/slice/analysis/ms/service/RateLimiter.java')
-rw-r--r-- | components/slice-analysis-ms/src/main/java/org/onap/slice/analysis/ms/service/RateLimiter.java | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/components/slice-analysis-ms/src/main/java/org/onap/slice/analysis/ms/service/RateLimiter.java b/components/slice-analysis-ms/src/main/java/org/onap/slice/analysis/ms/service/RateLimiter.java new file mode 100644 index 00000000..77ee61f2 --- /dev/null +++ b/components/slice-analysis-ms/src/main/java/org/onap/slice/analysis/ms/service/RateLimiter.java @@ -0,0 +1,59 @@ +/******************************************************************************* + * ============LICENSE_START======================================================= + * slice-analysis-ms + * ================================================================================ + * Copyright (C) 2022 Huawei Canada Limited. + * ============================================================================== + * 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. + * ============LICENSE_END========================================================= + * + *******************************************************************************/ +package org.onap.slice.analysis.ms.service; + +/** + * A simple rate-limiter; make sure bandwidth adjustment requests don't swarm underlying network controller + */ +class RateLimiter { + private int MAX_TOKENS; + private long lastRequestTime = System.currentTimeMillis(); + private long possibleTokens = 0; + private long interval = 1000; + + /** + * Constructor for rate limiter (simple token bucket filter) + * @param maxTokens max number of token allowed + * @param interval interval(ms) between received new token + */ + public RateLimiter(int maxTokens, int interval){ + MAX_TOKENS = maxTokens; + this.interval = interval; + } + + /** + * Trying to get a new token for execution, if no token left, stall for interval ms. + * @throws InterruptedException + */ + synchronized public void getToken() throws InterruptedException { + possibleTokens += (System.currentTimeMillis() - lastRequestTime) / interval; + if (possibleTokens > MAX_TOKENS){ + possibleTokens = MAX_TOKENS; + } + if (possibleTokens == 0){ + Thread.sleep(interval); + } else { + possibleTokens--; + } + // granting token + lastRequestTime = System.currentTimeMillis(); + } +} |