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package org.apidesign.html.json.spi;

import net.java.html.BrwsrCtx;

import org.apidesign.html.context.spi.Contexts.Provider;

/** Interface for providers of WebSocket protocol. Register into a 

 * {@link BrwsrCtx context} in your own {@link Provider}

 *

 * @author Jaroslav Tulach <jtulach@netbeans.org>

 * @param <WebSocket> internal implementation type representing the socket

 * @since 0.5

 */

public interface WSTransfer<WebSocket> {

    /** Initializes a web socket. The <code>callback</code> object should 

     * have mostly empty values: {@link JSONCall#isDoOutput()} should be 

     * <code>false</code> and thus there should be no {@link JSONCall#getMessage()}.

     * The method of connection {@link JSONCall#getMethod()} is "WebSocket".

     * Once the connection is open call {@link JSONCall#notifySuccess(java.lang.Object) notifySuccess(null)}.

     * When the server sends some data then, pass them to 

     * {@link JSONCall#notifySuccess(java.lang.Object) notifySuccess} method

     * as well. If there is an error call {@link JSONCall#notifyError(java.lang.Throwable)}.

     * 

     * @param url the URL to connect to

     * @param callback a way to provide results back to the client

     * @return your object representing the established web socket

     */

    public WebSocket open(String url, JSONCall callback);

    /** Sends data to the server. The most important value

     * of the <code>data</code> parameter is {@link JSONCall#getMessage()},

     * rest can be ignored.

     * 

     * @param socket internal representation of the socket

     * @param data the message to be sent

     */

    public void send(WebSocket socket, JSONCall data);

    /** A request to close the socket.

     * @param socket internal representation of the socket

     */

    public void close(WebSocket socket);

}