javax.websocket.server.ServerEndpointConfig Maven / Gradle / Ivy
/*
* Copyright (c) 2018 Oracle and/or its affiliates and others.
* All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package javax.websocket.server;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.ServiceLoader;
import javax.websocket.Decoder;
import javax.websocket.Encoder;
import javax.websocket.EndpointConfig;
import javax.websocket.Extension;
import javax.websocket.HandshakeResponse;
/**
* The ServerEndpointConfig is a special kind of endpoint configuration object that contains web socket configuration
* information specific only to server endpoints. For developers deploying programmatic endpoints, ServerEndpointConfig
* objects can be created using a {@link ServerEndpointConfig.Builder}. Certain configuration operations can be
* customized by providing a {@link ServerEndpointConfig.Configurator}
*
* @author dannycoward
*/
public interface ServerEndpointConfig extends EndpointConfig {
/**
* Returns the Class of the endpoint this configuration is configuring. If the endpoint is an annotated endpoint,
* the value is the class of the Java class annotated with @ServerEndpoint. if the endpoint is a programmatic, the
* value is the class of the subclass of Endpoint.
*
* @return the class of the endpoint, annotated or programmatic.
*/
Class getEndpointClass();
/**
* Return the path for this endpoint configuration. The path is the URI or URI-template (level 1) relative to the
* websocket root of the server to which the endpoint using this configuration will be mapped. The path is always
* non-null and always begins with a leading "/".
*
* @return the relative path for this configuration.
*/
String getPath();
/**
* Return the websocket subprotocols configured.
*
* @return the list of subprotocols, the empty list if none
*/
List getSubprotocols();
/**
* Return the websocket extensions configured.
*
* @return the list of extensions, the empty list if none.
*/
List getExtensions();
/**
* Return the {@link ServerEndpointConfig.Configurator} this configuration is using. If none was set by calling
* {@link ServerEndpointConfig.Builder#configurator(javax.websocket.server.ServerEndpointConfig.Configurator) } this
* methods returns the platform default configurator.
*
* @return the configurator in use.
*/
ServerEndpointConfig.Configurator getConfigurator();
/**
* The ServerEndpointConfig.Configurator class may be extended by developers who want to provide custom
* configuration algorithms, such as intercepting the opening handshake, or providing arbitrary methods and
* algorithms that can be accessed from each endpoint instance configured with this configurator.
*
* The implementation must provide a platform default configurator loading using the service loader.
*/
public class Configurator {
private ServerEndpointConfig.Configurator containerDefaultConfigurator;
static ServerEndpointConfig.Configurator fetchContainerDefaultConfigurator() {
for (ServerEndpointConfig.Configurator impl : ServiceLoader
.load(javax.websocket.server.ServerEndpointConfig.Configurator.class)) {
return impl;
}
throw new RuntimeException("Cannot load platform configurator");
}
ServerEndpointConfig.Configurator getContainerDefaultConfigurator() {
if (this.containerDefaultConfigurator == null) {
this.containerDefaultConfigurator = fetchContainerDefaultConfigurator();
}
return this.containerDefaultConfigurator;
}
/**
* Return the subprotocol the server endpoint has chosen from the requested list supplied by a client who wishes
* to connect, or none if there wasn't one this server endpoint liked. See
* Sending the Server's Opening Handshake.
* Subclasses may provide custom algorithms based on other factors.
*
*
* The default platform implementation of this method returns the first subprotocol in the list sent by the
* client that the server supports, or the empty string if there isn't one.
*
* @param requested the requested subprotocols from the client endpoint
* @param supported the subprotocols supported by the server endpoint
* @return the negotiated subprotocol or the empty string if there isn't one.
*/
public String getNegotiatedSubprotocol(List supported, List requested) {
return this.getContainerDefaultConfigurator().getNegotiatedSubprotocol(supported, requested);
}
/**
* Return the ordered list of extensions that t server endpoint will support given the requested extension list
* passed in, the empty list if none. See Negotiating
* Extensions
*
*
* The default platform implementation of this method returns a list containing all of the requested extensions
* passed to this method that it supports, using the order in the requested extensions, the empty list if none.
*
* @param installed the installed extensions on the implementation.
* @param requested the requested extensions, in the order they were requested by the client
* @return the list of extensions negotiated, the empty list if none.
*/
public List getNegotiatedExtensions(List installed, List requested) {
return this.getContainerDefaultConfigurator().getNegotiatedExtensions(installed, requested);
}
/**
* Check the value of the Origin header (See Origin Header) the
* client passed during the opening handshake.
*
*
* The platform default implementation of this method makes a check of the validity of the Origin header sent
* along with the opening handshake following the recommendation at:
* Sending the Server's Opening Handshake.
*
* @param originHeaderValue the value of the origin header passed by the client.
* @return whether the check passed or not
*/
public boolean checkOrigin(String originHeaderValue) {
return this.getContainerDefaultConfigurator().checkOrigin(originHeaderValue);
}
/**
* Called by the container after it has formulated a handshake response resulting from a well-formed handshake
* request. The container has already checked that this configuration has a matching URI, determined the
* validity of the origin using the checkOrigin method, and filled out the negotiated subprotocols and
* extensions based on this configuration. Custom configurations may override this method in order to inspect
* the request parameters and modify the handshake response that the server has formulated. and the URI checking
* also.
*
*
* If the developer does not override this method, no further modification of the request and response are made
* by the implementation.
*
* @param sec the configuration object involved in the handshake
* @param request the opening handshake request.
* @param response the proposed opening handshake response
*/
public void modifyHandshake(ServerEndpointConfig sec, HandshakeRequest request, HandshakeResponse response) {
// nothing.
}
/**
* This method is called by the container each time a new client connects to the logical endpoint this
* configurator configures. Developers may override this method to control instantiation of endpoint instances
* in order to customize the initialization of the endpoint instance, or manage them in some other way. If the
* developer overrides this method, services like dependency injection that are otherwise supported, for
* example, when the implementation is part of the Java EE platform may not be available. The platform default
* implementation of this method returns a new endpoint instance per call, thereby ensuring that there is one
* endpoint instance per client, the default deployment cardinality.
*
* @param endpointClass the class of the endpoint
* @param the type of the endpoint
* @return an instance of the endpoint that will handle all interactions from a new client.
* @throws InstantiationException if there was an error producing the endpoint instance.
*/
public T getEndpointInstance(Class endpointClass) throws InstantiationException {
return this.getContainerDefaultConfigurator().getEndpointInstance(endpointClass);
}
}
/**
* The ServerEndpointConfig.Builder is a class used for creating {@link ServerEndpointConfig.Builder} objects for
* the purposes of deploying a server endpoint.
*
*
* Here are some examples:
*
*
* Building a plain configuration for an endpoint with just a path.
*
*
*
* ServerEndpointConfig config = ServerEndpointConfig.Builder.create(ProgrammaticEndpoint.class, "/foo").build();
*
*
*
*
* Building a configuration with no subprotocols and a custom configurator.
*
*
*
* ServerEndpointConfig config = ServerEndpointConfig.Builder.create(ProgrammaticEndpoint.class, "/bar")
* .subprotocols(subprotocols)
* .configurator(new MyServerConfigurator())
* .build();
*
*
*
* @author dannycoward
*/
public final class Builder {
private String path;
private Class endpointClass;
private List subprotocols = Collections.emptyList();
private List extensions = Collections.emptyList();
private List> encoders = Collections.emptyList();
private List> decoders = Collections.emptyList();
private ServerEndpointConfig.Configurator serverEndpointConfigurator;
/**
* Creates the builder with the mandatory information of the endpoint class (programmatic or annotated), the
* relative URI or URI-template to use, and with no subprotocols, extensions, encoders, decoders or custom
* configurator.
*
* @param endpointClass the class of the endpoint to configure
* @param path The URI or URI template where the endpoint will be deployed. A trailing "/" will be
* ignored and the path must begin with /.
* @return a new instance of ServerEndpointConfig.Builder
*/
public static Builder create(Class endpointClass, String path) {
return new Builder(endpointClass, path);
}
// only one way to build them
private Builder() {
}
/**
* Builds the configuration object using the current attributes that have been set on this builder object.
*
* @return a new ServerEndpointConfig object.
*/
public ServerEndpointConfig build() {
return new DefaultServerEndpointConfig(this.endpointClass, this.path, this.subprotocols, this.extensions,
this.encoders, this.decoders, this.serverEndpointConfigurator);
}
private Builder(Class endpointClass, String path) {
if (endpointClass == null) {
throw new IllegalArgumentException("endpointClass cannot be null");
}
this.endpointClass = endpointClass;
if (path == null || !path.startsWith("/")) {
throw new IllegalStateException("Path cannot be null and must begin with /");
}
this.path = path;
}
/**
* Sets the list of encoder implementation classes for this builder.
*
* @param encoders the encoders
* @return this builder instance
*/
public ServerEndpointConfig.Builder encoders(List> encoders) {
this.encoders = (encoders == null) ? new ArrayList>() : encoders;
return this;
}
/**
* Sets the decoder implementation classes to use in the configuration.
*
* @param decoders the decoders
* @return this builder instance.
*/
public ServerEndpointConfig.Builder decoders(List> decoders) {
this.decoders = (decoders == null) ? new ArrayList>() : decoders;
return this;
}
/**
* Sets the subprotocols to use in the configuration.
*
* @param subprotocols the subprotocols.
* @return this builder instance
*/
public ServerEndpointConfig.Builder subprotocols(List subprotocols) {
this.subprotocols = (subprotocols == null) ? new ArrayList() : subprotocols;
return this;
}
/**
* Sets the extensions to use in the configuration.
*
* @param extensions the extensions to use.
* @return this builder instance.
*/
public ServerEndpointConfig.Builder extensions(List extensions) {
this.extensions = (extensions == null) ? new ArrayList() : extensions;
return this;
}
/**
* Sets the custom configurator to use on the configuration object built by this builder.
*
* @param serverEndpointConfigurator the configurator
* @return this builder instance
*/
public ServerEndpointConfig.Builder configurator(ServerEndpointConfig.Configurator serverEndpointConfigurator) {
this.serverEndpointConfigurator = serverEndpointConfigurator;
return this;
}
}
}