package org.codehaus.xfire.handler;import java.util.List;import javax.xml.namespace.QName;import org.codehaus.xfire.MessageContext;import org.codehaus.xfire.fault.XFireFault;/** * <p> * A handler is just something that processes an XML message. * </p> * <p> * If an exception occurrs in the invoke method, the entity which * started the invocation, is responsible for turning the exception * into a fault. * </p> *  * @author <a href="mailto:dan@envoisolutions.com">Dan Diephouse </a> * @since Feb 18, 2004 */public interface Handler{    String ROLE = Handler.class.getName();    /**     * @return null or an empty array if there are no headers.     */    QName[] getUnderstoodHeaders();    /**     * The roles which this service applies to.     *      * @return <code>null</code> or an empty if this endpoint handles no     *         roles.     */    String[] getRoles();    /**     * The phase which this handler would like to be in.     *      * @return     * @see Phase     */    String getPhase();        /**     * Invoke a handler. If a fault occurs it will be handled via the     * <code>handleFault</code> method.     *      * @param message     *            The message context.     */    void invoke(MessageContext context)        throws Exception;    /**     * Handles faults that occur in this handler. This is not responsible for     * actually writing the fault response message.     *      * @param context     */    void handleFault(XFireFault fault, MessageContext context);        public List getAfter();        public List getBefore();}