package com.onaro.sanscreen.client.help;

/**
 * Class that instantiates HelpManager objects.  This class looks for a system property that is set to the name of a implementation
 * of the IHelpManager interface. 
 * 
 * @author rnoel
 *
 */
public class HelpManagerFactory {

    /* The name of the system property holding the IHelpManager implementation class */
    private static final String HELP_MANAGER_CLASS_NAME = "help.manager.class"; //$NON-NLS-1$
    
    // Singleton
    private static final HelpManagerFactory INSTANCE = new HelpManagerFactory();
    
    private IHelpManager helpManager;// Single help manager
    
    private HelpManagerFactory() {
        //TODO: make this an extension point of a new help plugin.
        String helpManagerClassName = System.getProperty(HELP_MANAGER_CLASS_NAME, "com.onaro.sanscreen.client.help.HelpManager"); //$NON-NLS-1$
        
        if(helpManagerClassName != null) {
            try {
                @SuppressWarnings("unchecked")
                Class<IHelpManager> cl = (Class<IHelpManager>)Class.forName(helpManagerClassName);
                
                helpManager = cl.newInstance();
            }
            catch(Exception e) {
                // Report and create default help manager that does nothing
                e.printStackTrace();
                System.out.println("Online help will not be functional."); //$NON-NLS-1$
            }
        }
        if(helpManager == null) {
            helpManager = new DefaultHelpManager();
        }
    }
    
    public static IHelpManager getHelpManager() {
        return(INSTANCE.helpManager);
    }
}