Question

I have a ServiceLocator shown below

public class ServiceLocator {
    private static ServiceLocator serviceLocator = null;
    InitialContext context = null;
    HashMap serviceCache = null;

    public ServiceLocator() throws NamingException {
        context = new InitialContext();
        serviceCache = new HashMap(5);
    }

    public synchronized static ServiceLocator getInstance()
            throws NamingException {
        if (serviceLocator == null) {
            serviceLocator = new ServiceLocator();
        }
        return serviceLocator;
    }

    public Object getService(String jndiName) throws NamingException {
        if (!serviceCache.containsKey(jndiName)) {
            serviceCache.put(jndiName, context.lookup(jndiName));
        }
        return serviceCache.get(jndiName);
    }
}

Could anybody tell me why does we need to store JNDI name in this way ??

serviceCache.put(jndiName, context.lookup(jndiName));

Answer 1

Who says you need to do that? It’s just caching the results of the JNDI lookup. Under certain circumstances, JNDI lookups can be slow, so caching them may be a good idea.

I’d find out if you really need to do this, though. The JNDI lookups may be fast enough on their own. If so, then take the serviceCache out.