test/unit/org/apache/cassandra/metrics/MaxSamplerTest.java

/*
 * 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.metrics;

import java.util.List;
import java.util.concurrent.TimeoutException;

import org.apache.cassandra.metrics.Sampler.Sample;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;

public class MaxSamplerTest extends SamplerTest
{
    @Before
    public void setSampler()
    {
        this.sampler = new MaxSampler<String>()
        {
            public String toString(String value)
            {
                return value;
            }
        };
    }

    @Test
    public void testReturnsMax() throws TimeoutException
    {
        sampler.beginSampling(5, 100000);
        add();
        List<Sample<String>> result = sampler.finishSampling(10);
        for (int i = 9995 ; i < 10000 ; i ++)
        {
            final String key = "test" + i;
            Assert.assertTrue(result.stream().anyMatch(s -> s.value.equals(key)));
        }
    }

    @Test
    public void testSizeEqualsCapacity() throws TimeoutException
    {
        sampler.beginSampling(10, 100000);
        add();
        List<Sample<String>> result = sampler.finishSampling(10);
        for (int i = 9990 ; i < 10000 ; i ++)
        {
            final String key = "test" + i;
            Assert.assertTrue(result.stream().anyMatch(s -> s.value.equals(key)));
        }
    }

    @Test
    public void testCapacityLarger() throws TimeoutException
    {

        sampler.beginSampling(100, 100000);
        add();
        List<Sample<String>> result = sampler.finishSampling(10);
        for (int i = 9990 ; i < 10000 ; i ++)
        {
            final String key = "test" + i;
            Assert.assertTrue(result.stream().anyMatch(s -> s.value.equals(key)));
        }
    }

    private void add() throws TimeoutException
    {
        for (int i = 0 ; i < 10000 ; i ++)
        {
            // dont load shed test data
            if (i % 999 == 0)
                waitForEmpty(1000);
            sampler.addSample("test"+i, i);
        }
        waitForEmpty(1000);
    }
}