ru.saidgajiev.ormnext.cache.LRUObjectCache Maven / Gradle / Ivy

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package ru.saidgajiev.ormnext.cache;

import ru.saidgadjiev.ormnext.core.cache.ObjectCache;

import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * Cache with LRU caching algorithm.
 *
 * @author Said Gadjiev
 */
public class LRUObjectCache implements ObjectCache {

    /**
     * Default cache size.
     */
    private static final int DEFAULT_CACHE_SIZE = 16;

    /**
     * Cached classes map.
     */
    private Map, Map> cache = new ConcurrentHashMap<>();

    /**
     * Max cache size.
     */
    private int maxSize;

    /**
     * Create a new instance.
     *
     * @param maxSize target max size
     */
    public LRUObjectCache(int maxSize) {
        this.maxSize = maxSize;
    }

    /**
     * Create a new instance with default max size.
     */
    public LRUObjectCache() {
        this.maxSize = DEFAULT_CACHE_SIZE;
    }

    @Override
    public void registerClass(Class tClass) {
        cache.computeIfAbsent(tClass, k -> createLRUMap(maxSize));
    }

    @Override
    public void put(Class tClass, Object id, Object data) {
        Map objectCache = cache.get(tClass);

        if (objectCache != null) {
            objectCache.put(id, data);
        }
    }

    @Override
    public Object get(Class tClass, Object id) {
        Map objectCache = cache.get(tClass);

        if (objectCache == null) {
            return null;
        }

        return objectCache.get(id);
    }

    @Override
    public Collection