Bug 176450 Support link to CSS Feature(Model Part)
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Module.java
* Gets the resource folder set in this session.
	 * 
	 * @return the resource folder set in this session
	 */
	public String getResourceFolder( )
	{
		ModuleOption effectOptions = getOptions( );
		if ( effectOptions == null )
			return null;
		return effectOptions.getResourceFolder( );
	}
	/**
	 * Sets the module is read-only one. That means any operation on it will
	 * throw runtime exception.
	 */
	public void setReadOnly( )
	{
		activityStack = new ReadOnlyActivityStack( );
	}
	/**
	 * Returns the module namespace. Only included library has a non-empty
	 * namespace.
	 * 
	 * @return the module namespace
	 */
	public String getNamespace( )
	{
		return null;
	}
}