Tukukkk

I am trying to come up with design for different types of cache with different eviction policies but I am facing difficulty linking the eviction policy with cache. It will really helpful if this can be reviewed and I get some pointers on how to do it.

Here's what I have worked upon till now:

Cache.java

public interface Cache {



    String get(String key);



    boolean set(String key, String value);



    void evict();



    EvictionPolicy getEvictionPolicy();



    void startEvictor(long delay);

}

EvictionPolicy

public interface EvictionPolicy {

    //Scheduled execution of this method examines the cache key

    //if it can be evicted return true else false

    boolean evict();

}

CacheConfig.java

public class CacheConfig {



    private EvictionPolicy evictionPolicy;



    public EvictionPolicy getEvictionPolicy() {

        return evictionPolicy;

    }



    public void setEvictionPolicy(EvictionPolicy evictionPolicy) {

        this.evictionPolicy = evictionPolicy;

    }

}

BaseCache.java

import java.util.concurrent.ScheduledThreadPoolExecutor;

import java.util.concurrent.ThreadFactory;

import java.util.concurrent.TimeUnit;



public class BaseCache implements Cache{



    private volatile EvictionPolicy evictionPolicy;



    private Evictor evictor = null;



    public BaseCache(CacheConfig config) {

        setConfig(config);

    }



    public void setConfig(CacheConfig config){

        setEvictionPolicy(config.getEvictionPolicy());

    }



    public void setEvictionPolicy(final EvictionPolicy evictionPolicy) {

        this.evictionPolicy = evictionPolicy;

    }



    @Override

    public void evict() {

        EvictionPolicy evictionPolicy = getEvictionPolicy();

        evictionPolicy.evict();

    }



    @Override

    public EvictionPolicy getEvictionPolicy() {

        return evictionPolicy;

    }



    @Override

    public String get(String key) {

        return null;

    }



    @Override

    public boolean set(String key, String value) {

        return false;

    }



    public void startEvictor(final long delay) {

        if (delay > 0) {

            evictor = new Evictor();

            ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(1, new EvictorThreadFactory());

            executor.scheduleWithFixedDelay(evictor, delay, delay, TimeUnit.MILLISECONDS);

        }

    }



    class Evictor implements Runnable {



        @Override

        public void run() {

            try {

                evict();

            } catch(final Exception e) {

                System.out.println("Swallow exception!!");

            }

        }

    }



    private static class EvictorThreadFactory implements ThreadFactory {



        @Override

        public Thread newThread(final Runnable runnable) {

            return new Thread(null, runnable, "evictor-thread");

        }

    }

}

DefaultEvictionPolicy

 public class DefaultEvictionPolicy implements EvictionPolicy {



    @Override

    public boolean evict() {

        return true;

    }

}

LruCache

public class LruCache extends BaseCache {



    private Map<String, String> cachedObjects = new ConcurrentHashMap<>();



    public LruCache(CacheConfig config) {

        super(config);

        setConfig(config);

    }



    public void setConfig(CacheConfig config){

        super.setConfig(config);

        setEvictionPolicy(config.getEvictionPolicy());

    }



    @Override

    public void evict() {

        EvictionPolicy evictionPolicy = getEvictionPolicy();

        evictionPolicy.evict();

    }





    @Override

    public String get(String key) {

        return null;

    }



    @Override

    public boolean set(String key, String value) {

        return false;

    }

}

Main.java

public class Main {

    public static void main(String args) {



        CacheConfig config = new CacheConfig();

        config.setEvictionPolicy(new DefaultEvictionPolicy());



        Cache cache = new LruCache(config);



        cache.set("key1", "10");

        cache.set("key2", "12");

        cache.get("key1");

        cache.startEvictor(5);

    }

}