io.mapsmessaging.storage.impl.cache.CacheLayer Maven / Gradle / Ivy

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/*
 *   Copyright [2020 - 2022]   [Matthew Buckton]
 *
 *    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 io.mapsmessaging.storage.impl.cache;

import io.mapsmessaging.storage.LayeredStorage;
import io.mapsmessaging.storage.Statistics;
import io.mapsmessaging.storage.Storable;
import io.mapsmessaging.storage.Storage;
import io.mapsmessaging.storage.impl.file.TaskQueue;
import io.mapsmessaging.storage.tasks.Completion;
import io.mapsmessaging.utilities.threads.tasks.TaskScheduler;
import java.io.IOException;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.atomic.LongAdder;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

public class CacheLayer implements LayeredStorage {

  private final boolean enableWriteThrough;
  private final Cache cache;
  private final Storage baseStorage;

  private final LongAdder cacheMiss = new LongAdder();
  private final LongAdder cacheHit = new LongAdder();

  public CacheLayer(boolean enableWriteThrough, @NotNull Cache cache, @NotNull Storage baseStorage) {
    this.baseStorage = baseStorage;
    this.enableWriteThrough = enableWriteThrough;
    this.cache = cache;
  }

  @Override
  public void shutdown() throws IOException {
    baseStorage.shutdown();
  }

  @Override
  public String getName() {
    return baseStorage.getName();
  }

  @Override
  public void delete() throws IOException {
    cache.cacheDelete();
    baseStorage.delete();
  }

  @Override
  public boolean supportPause() {
    return baseStorage.supportPause();
  }

  @Override
  public void pause() throws IOException {
    baseStorage.pause();
  }

  @Override
  public void resume() throws IOException {
    baseStorage.resume();
  }

  @Override
  public void add(@NotNull T object, Completion completion) throws IOException {
    cache.cachePut(object);
    if (enableWriteThrough && completion != null) {
      completion.onCompletion(object);
    }
    baseStorage.add(object);
  }

  @Override
  public void add(@NotNull T object) throws IOException {
    cache.cachePut(object);
    baseStorage.add(object);
  }

  @Override
  public boolean remove(long key) throws IOException {
    cache.cacheRemove(key);
    return baseStorage.remove(key);
  }

  @Override
  public long size() throws IOException {
    return baseStorage.size();
  }

  @Override
  public long getLastKey() {
    return baseStorage.getLastKey();
  }

  @Override
  public long getLastAccess() {
    return baseStorage.getLastAccess();
  }

  @Override
  public boolean isEmpty() {
    return baseStorage.isEmpty();
  }

  @Override
  public TaskQueue getTaskScheduler() {
    return baseStorage.getTaskScheduler();
  }

  @Override
  public @NotNull Collection keepOnly(@NotNull Collection listToKeep) throws IOException {
    cache.cacheClear();
    return baseStorage.keepOnly(listToKeep);
  }

  @Override
  public int removeAll(@NotNull Collection listToRemove) throws IOException {
    cache.cacheClear();
    return baseStorage.removeAll(listToRemove);
  }

  @Override
  public void close() throws IOException {
    cache.cacheDelete();
    baseStorage.close();
  }

  @Override
  public @Nullable T get(long key) throws IOException {
    T obj = cache.cacheGet(key);
    if (obj == null) {
      cacheMiss.increment();
      obj = baseStorage.get(key);
      if (obj != null) {
        cache.cachePut(obj);
      }
    } else {
      baseStorage.updateLastAccess();
      cacheHit.increment();
    }
    return obj;
  }

  @Override
  public @NotNull List getKeys() {
    return baseStorage.getKeys();
  }

  @Override
  public boolean contains(long key) {
    return baseStorage.contains(key);
  }

  @Override
  public void setExecutor(TaskScheduler scheduler) {
    baseStorage.setExecutor(scheduler);
  }

  public @NotNull Statistics getStatistics() {
    return new CacheStatistics(cacheMiss.sumThenReset(), cacheHit.sumThenReset(), cache.size(), baseStorage.getStatistics());
  }
}