ex7_8.txt

j2ee core design patterns

Example 7.8 	ServiceLocator.java: Implementing JDBC DataSource Service Locator Strategy
package com.corej2eepatterns.servicelocator;

// imports
public class ServiceLocator {
    . . . 

    public DataSource getDataSource(String dataSourceName) 
    throws ServiceLocatorException {
        DataSource dataSource = null;
        try {
            if (cache.containsKey(dataSourceName)) {
                dataSource =
                    (DataSource) cache.get(dataSourceName);
            } else {
                dataSource = (DataSource) 
                    initialContext.lookup(dataSourceName);
                cache.put(dataSourceName, dataSource );
            }
        } catch (NamingException nex) {
            throw new ServiceLocatorException(nex);
        } catch (Exception ex) {
            throw new ServiceLocatorException(ex);
        }
        return dataSource;
    }
    . . .
}