java-design-patterns/service-locator/src/main/java/com/iluwatar/ServiceCache.java

package com.iluwatar;

import java.util.HashMap;
import java.util.Map;

/**
 * The service cache implementation which will cache services that are being created.
 * On first hit, the cache will be empty and thus any service that is being requested, will be 
 * created fresh and then placed into the cache map. On next hit, if same service name will
 * be requested, it will be returned from the cache 
 * @author saifasif
 *
 */
public class ServiceCache {
	
	private Map<String, Service> serviceCache;

	public ServiceCache() {
		serviceCache = new HashMap<String, Service>();
	}

	/**
	 * Get the service from the cache. null if no service is found matching the 
	 * name
	 * @param serviceName
	 * @return {@link Service}
	 */
	public Service getService(String serviceName){
		Service cachedService = null;
		for (String serviceJndiName : serviceCache.keySet()){
			if( serviceJndiName.equals( serviceName ) ){
				cachedService = serviceCache.get(serviceJndiName);
				System.out.println("(cache call) Fetched service " + cachedService.getName() + "("+cachedService.getId()+") from cache... !");
			}
		}
		return cachedService;
	}

	/**
	 * Adds the service into the cache map
	 * @param newService
	 */
	public void addService(Service newService){
		serviceCache.put(newService.getName(), newService);
	}
}