private static final Schema getSchemaFromFile(final SchemaFactoryProvider sfp,
			File... systemID) throws JDOMException {
		if (systemID == null) {
			throw new NullPointerException("Cannot specify a null input array");
		}
		if (systemID.length == 0) {
			throw new IllegalArgumentException("You need at least one " +
					"XSD source for an XML Schema validator");
		}
		Source[] sources = new Source[systemID.length];
		for (int i = 0; i < systemID.length; i++) {
			if (systemID[i] == null) {
				throw new NullPointerException("Cannot specify a null SystemID");
			}
			sources[i] = new StreamSource(systemID[i]);
		}
		return getSchemaFromSource(sfp, sources);
	}