content: /*
   * 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.activemq.artemis.cli.commands.messages.perf;
  
  import java.util.function.LongSupplier;
  
  public final class RateSampler implements Runnable {
  
     private final LongSupplier sampling;
     private long lastSample;
     private long lastSampleTime;
     private long rate;
     private long timeSpanNs;
  
     private RateSampler(final LongSupplier sampling) {
        this.sampling = sampling;
        this.timeSpanNs = 0;
        this.lastSampleTime = System.nanoTime();
        this.lastSample = sampling.getAsLong();
        this.rate = 0;
     }
  
     @Override
     public void run() {
        final long now = System.nanoTime();
        final long newSample = sampling.getAsLong();
        rate = newSample - lastSample;
        timeSpanNs = now - lastSampleTime;
        lastSample = newSample;
        lastSampleTime = now;
     }
  
     public long getLastSample() {
        return lastSample;
     }
  
     public long reportRate(final long reportIntervalNs) {
        return (rate * reportIntervalNs) / timeSpanNs;
     }
  
     public static RateSampler of(final LongSupplier sampling) {
        return new RateSampler(sampling);
     }
  
  }
  