org.apache.aurora.scheduler.storage.db.MyBatisCacheImpl.java Source code

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Here is the source code for org.apache.aurora.scheduler.storage.db.MyBatisCacheImpl.java

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/**
 * 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.apache.aurora.scheduler.storage.db;

import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.ReadWriteLock;

import com.google.common.base.Preconditions;
import com.google.common.base.Supplier;
import com.google.common.cache.CacheBuilder;
import com.google.common.primitives.Ints;

import org.apache.aurora.common.stats.StatImpl;
import org.apache.aurora.common.stats.Stats;
import org.apache.ibatis.cache.Cache;

import static java.util.Objects.requireNonNull;

public class MyBatisCacheImpl implements Cache {
    private com.google.common.cache.Cache<Object, Object> delegate;
    private final String id;
    private Integer size;
    private final AtomicInteger clearCount = new AtomicInteger(0);

    public MyBatisCacheImpl(String id) {
        this.id = requireNonNull(id);
    }

    public void setSize(Integer size) {
        this.size = requireNonNull(size);
        initCache();
    }

    private void initCache() {
        Preconditions.checkState(delegate == null);
        requireNonNull(size);

        delegate = CacheBuilder.newBuilder().maximumSize(size).recordStats().softValues().build();
        initStats();
    }

    private void initStats() {
        makeStat("request_count", () -> delegate.stats().requestCount());
        makeStat("hit_count", () -> delegate.stats().hitCount());
        makeStat("hit_rate", () -> delegate.stats().hitRate());
        makeStat("miss_count", () -> delegate.stats().missCount());
        makeStat("miss_rate", () -> delegate.stats().missRate());
        makeStat("eviction_count", () -> delegate.stats().evictionCount());
        makeStat("size", () -> delegate.size());
        makeStat("clear_count", clearCount::get);
    }

    private <T extends Number> void makeStat(String name, Supplier<T> supplier) {
        String prefix = "db_storage_mybatis_cache_" + id + "_";
        Stats.export(new StatImpl<Number>(prefix + name) {
            @Override
            public Number read() {
                return supplier.get();
            }
        });
    }

    @Override
    public String getId() {
        return id;
    }

    @Override
    public void putObject(Object key, Object value) {
        if (key == null || value == null) {
            return;
        }
        delegate.put(key, value);
    }

    @Override
    public Object getObject(Object key) {
        return delegate.getIfPresent(key);
    }

    @Override
    public Object removeObject(Object key) {
        delegate.invalidate(key);
        // MyBatis says the return value is not used.
        return null;
    }

    @Override
    public void clear() {
        delegate.invalidateAll();
        clearCount.incrementAndGet();
    }

    @Override
    public int getSize() {
        return Ints.saturatedCast(delegate.size());
    }

    @Override
    public ReadWriteLock getReadWriteLock() {
        // MyBatis says this value is no longer used.
        return null;
    }
}