javax.websocket.server.ServerEndpoint Maven / Gradle / Ivy

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package javax.websocket.server;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import javax.websocket.Decoder;
import javax.websocket.Encoder;

/**
 * This class level annotation declares that the class it decorates
 * is a web socket endpoint that will be deployed and made available in the URI-space
 * of a web socket server. The annotation allows the developer to
 * define the URL (or URI template) which this endpoint will be published, and other
 * important properties of the endpoint to the websocket runtime, such as the encoders
 * it uses to send messages.
 *
 * The annotated class
 * must have a public no-arg constructor.
 *
 * 
For example:
 * 

 * @ServerEndpoint("/hello");
 * public class HelloServer {
 *
 *     @OnMessage
 *     public void processGreeting(String message, Session session) {
 *         System.out.println("Greeting received:" + message);
 *     }
 *
 * }
 * 
 *
 * @author dannycoward
 */
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
public @interface ServerEndpoint {

    /**
     * The URI or URI-template, level-1 (See RFC 6570) where the endpoint will be deployed. The URI us relative to the
     * root of the web socket container and must begin with a leading "/". Trailing "/"'s are ignored. Examples:
     * 
     * @ServerEndpoint("/chat")
     * @ServerEndpoint("/chat/{user}")
     * @ServerEndpoint("/booking/{privilege-level}")
     * 
     *
     * @return the URI or URI-template
     */
    public String value();

    /**
     * The ordered array of web socket protocols this endpoint supports.
     * For example, {"superchat", "chat"}.
     *
     * @return the subprotocols.
     */
    public String[] subprotocols() default {};

    /**
     * The ordered array of decoder classes this endpoint will use. For example,
     * if the developer has provided a MysteryObject decoder, this endpoint will be able to
     * receive MysteryObjects as web socket messages. The websocket runtime will use the first
     * decoder in the list able to decode a message, ignoring the remaining decoders.
     *
     * @return the decoders.
     */
    public Class[] decoders() default {};

    /**
     * The ordered array of encoder classes this endpoint will use. For example,
     * if the developer has provided a MysteryObject encoder, this class will be able to
     * send web socket messages in the form of MysteryObjects. The websocket runtime will use the first
     * encoder in the list able to encode a message, ignoring the remaining encoders.
     *
     * @return the encoders.
     */
    public Class[] encoders() default {};


    /**
     * The optional custom configurator class that the developer would like to use
     * to further configure new instances of this endpoint. If no configurator
     * class is provided, the implementation uses its own.  The implementation
     * creates a new instance of the configurator per logical endpoint.
     * 
     * @return the custom configuration class, or ServerEndpointConfig.Configurator.class
     * if none was set in the annotation.
     */
    public Class configurator() default ServerEndpointConfig.Configurator.class;
}