cassandra-trunk/test/unit/org/apache/cassandra/auth/CacheRefresherTest.java
/*
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 * 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
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 */

package org.apache.cassandra.auth;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.function.BooleanSupplier;

import com.google.common.util.concurrent.MoreExecutors;

import com.github.benmanes.caffeine.cache.CacheLoader;
import com.github.benmanes.caffeine.cache.Caffeine;
import com.github.benmanes.caffeine.cache.LoadingCache;
import org.junit.Assert;
import org.junit.Test;

public class CacheRefresherTest
{
    @Test
    public void refresh() throws Exception
    {
        Map<String, String> src = new HashMap<>();
        CacheLoader<String, String> loader = src::get;

        // Supply the directExecutor so the refresh() call executes within the refresher task like AuthCache (rather than async)
        LoadingCache<String, String> cache = Caffeine.newBuilder()
                                                     .executor(MoreExecutors.directExecutor())
                                                     .build(loader);

        AtomicBoolean skipRefresh = new AtomicBoolean(false);
        BooleanSupplier skipCondition = skipRefresh::get;

        CacheRefresher<String, String> refresher = CacheRefresher.create("test", cache, (k, v) -> v.equals("removed"), skipCondition);
        src.put("some", "thing");
        Assert.assertEquals("thing", cache.get("some"));

        // Cache should still have old value...
        src.put("some", "one");
        Assert.assertEquals("thing", cache.get("some"));

        // ... but refresher should update it
        refresher.run();
        Assert.assertEquals("one", cache.get("some"));

        // If we just remove the value from the src, the cache should still contain it
        src.remove("some");
        Assert.assertEquals("one", cache.get("some"));

        // If we insert the special sentinel value into the src, the refresher will invalidate it from the cache.
        // This time when it's removed from the underlying storage, it's not returned from the cache
        src.put("some", "removed");
        refresher.run();
        src.remove("some");

        // Remove from src
        Assert.assertNull(cache.get("some"));

        // If the skip condition returns true, don't refresh
        src.put("some", "one");
        Assert.assertEquals("one", cache.get("some"));
        skipRefresh.set(true);
        src.put("some", "body");
        refresher.run();
        Assert.assertEquals("one", cache.get("some"));

        // Change the skip condition back to false and refresh
        skipRefresh.set(false);
        refresher.run();
        Assert.assertEquals("body", cache.get("some"));
    }
}
