A simple java cache. use the 'guava-libraries'

GuavaCacheTest.java

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.UUID;
import java.util.concurrent.TimeUnit;

import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;

public class GuavaCacheTest {
  
	public static class Value {
		String id;
		String createYmdt;
		
		public Value() {
			this.id = UUID.randomUUID().toString();
			this.createYmdt = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS").format(new Date());
		}
		
		public String toString() {
			return "[" + createYmdt + "]:" + id;
		}
	}
	
	public static Cache<String, Value> cache = CacheBuilder.newBuilder()
								.maximumSize(10)
								.expireAfterWrite(3000, TimeUnit.MILLISECONDS)
								.build();
	
	public static void main(String[] args) {
		
		System.out.println("startUp");
		
		try {
			Value val = cache.getIfPresent("key1");
			if ( val == null) cache.put("key1", new Value());
			
			// If maximum cache put
			for ( int n=0; n<15; n++) { 
				try {
					cache.put("k" + n, new Value());
					System.out.println("cache size=" + cache.size());
				} catch ( Exception e) {
					// If maximum put. not exception occurred.
					e.printStackTrace();
				}
			}
			
			for ( int i=0; i<30; i++) {
				Value v = cache.getIfPresent("key1");
				if ( v != null) {
					System.out.println(String.format("(Hit) %d - %s", i, v));
				} else {
					System.out.println("(Refresh)");
					cache.put("key1", new Value());
				}
				System.out.println("cache size=" + cache.size());
				Thread.sleep(1000);
			}
			
			cache.cleanUp();
			
			System.out.println("cleanUp");
			
		} catch ( Exception e) {
			e.printStackTrace();
		}
	}
	
}