Bug 197228 Need updaet createdBy info when serialize the module
When open module, designer will pass the property map which contains the createdBy info. this info should be retained by moduleHandle and then be updated and written when doing serialization. Note if this info is null, model should not update it during serialization. This could happen for api users or third-party designer. For BIRT designer, it will guarantee this value always not null.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Module.java
ThreadResources.getLocale( ) ) );
		return new ArrayList( keys );
	}
	/**
	 * Checks if the file with <code>fileName</code> exists. The search steps
	 * are described in {@link #findResource(String, int)}.
	 * 
	 * @param fileName
	 *            the file name to check
	 * @param fileType
	 *            the file type
	 * @return true if the file exists, false otherwise.
	 */
	public boolean isFileExist( String fileName, int fileType )
	{
		URL url = findResource( fileName, fileType );
		return url != null;
	}
	/**
	 * Gets a list containing all the include libraries.
	 * 
	 * @return a list containing all the include libraries. Return
	 *         <code>null</code> if there were no include libraries defined.
	 */
	public List getIncludedLibraries( )
	{
		List libs = (List) getLocalProperty( this, LIBRARIES_PROP );
		if ( libs == null )
			return Collections.EMPTY_LIST;
		return Collections.unmodifiableList( libs );