//
// $Id: InvocationService.java,v 1.2 2003/03/04 01:26:30 mdb Exp $

package com.threerings.presents.client;

/**
 * Serves as the base interface for invocation services. An invocation
 * service can be defined by extending this interface and defining service
 * methods, as well as response listeners (which must extend {@link
 * InvocationListener}). For example:
 *
 * <pre>
 * public interface LocationService extends InvocationService
 * {
 *     
 *     // Used to communicate responses to moveTo() requests.
 *     public interface MoveListener extends InvocationListener
 *     {
 *         // Called in response to a successful moveTo() request.
 *         public void moveSucceeded (PlaceConfig config);
 *     }
 *
 *     // Requests that this client's body be moved to the specified
 *     // location.
 *     //
 *     // @param placeId the object id of the place object to which the
 *     // body should be moved.
 *     // @param listener the listener that will be informed of success or
 *     // failure.
 *     public void moveTo (int placeId, MoveListener listener);
 * }
 * </pre>
 *
 * From this interface, a <code>LocationProvider</code> interface will be
 * generated which should be implemented by whatever server entity that
 * will actually provide the server side of this invocation service. That
 * provider interface would look like the following:
 *
 * <pre>
 * public interface LocationProvider extends InvocationProvider
 * {
 *      // Requests that this client's body be moved to the specified
 *      // location.
 *      //
 *      // @param caller the client object of the client that invoked this
 *      // remotely callable method.
 *      // @param placeId the object id of the place object to which the
 *      // body should be moved.
 *      // @param listener the listener that should be informed of success
 *      // or failure.
 *     public void moveTo (ClientObject caller, int placeId,
 *                         MoveListener listener)
 *         throws InvocationException;
 * }
 * </pre>
 */
public interface InvocationService
{
    /**
     * Invocation service methods that require a response should take a
     * listener argument that can be notified of request success or
     * failure. The listener argument should extend this interface so that
     * generic failure can be reported in all cases. For example:
     *
     * <pre>
     * // Used to communicate responses to <code>moveTo</code> requests.
     * public interface MoveListener extends InvocationListener
     * {
     *     // Called in response to a successful <code>moveTo</code>
     *     // request.
     *     public void moveSucceeded (PlaceConfig config);
     * }
     * </pre>
     */
    public static interface InvocationListener
    {
        /**
         * Called to report request failure. If the invocation services
         * system detects failure of any kind, it will report it via this
         * callback. Particular services may also make use of this
         * callback to report failures of their own, or they may opt to
         * define more specific failure callbacks.
         */
        public void requestFailed (String cause);
    }

    /**
     * Extends the {@link InvocationListener} with a basic success
     * callback.
     */
    public static interface ConfirmListener extends InvocationListener
    {
        /**
         * Indicates that the request was successfully processed.
         */
        public void requestProcessed ();
    }

    /**
     * Extends the {@link InvocationListener} with a basic success
     * callback that delivers a result object.
     */
    public static interface ResultListener extends InvocationListener
    {
        /**
         * Indicates that the request was successfully processed.
         */
        public void requestProcessed (Object result);
    }
}
