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 final 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 a string
     * @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 a {@link Service}
     */
    public void addService(Service newService) {
        serviceCache.put(newService.getName(), newService);
    }
}