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package javax.websocket.server;
import java.net.URI;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
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 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 interface may be implemented 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 abstract 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);
}
/**
* This default implementation matches the incoming path to the configuration's URI or URI template if and only if
* it is an exact match in the case the configuration is a URI, and if and only if it is a valid
* expansion of the configuration URI template, in the case where the configuration is a URI template. Subclasses may override this method to provide
* different matching policies.
*
* @param uri the URL of the incoming request
* @return whether it matched this configuration or not.
*/
/**
* Answers whether the incoming handshake request uri matches the
* path of the server endpoint. This method may be overridden
* by implementations with any number of algorithms for determining a match.
* If the path is a URI-template, and the implementation of this method
* determines there is a match of some kind, the implementation must add
* the path variable and values to the template expansion map passed into
* this method.
*
*
The platform default implementation matches the incoming uri to the
* configuration's path if and only if it is an exact match
* in the case the path is a URI, and if and only if it is a valid
* URI-template expansion of the path, in the case where the
* path is a URI template. In this latter case, all the path variables
* and values are added to the template expansion map.
*
* @param templateExpansion an empty Map to hold URI-template expansion
* names and values.
* @param path the path (URI or URI template) of the server endpoint
* @param requestUri the uri of the incoming handshake.
* @return whether there was a match
*/
public boolean matchesURI(String path, URI requestUri, Map templateExpansion) {
return this.getContainerDefaultConfigurator().matchesURI(path, requestUri, templateExpansion);
}
/**
* The default server configuration does not make any changes to the response.
* Subclasses may override this method in order to inspect the Http request
* headers of the opening handshake, for example to track cookies
* sent by the client. Additionally subclasses may choose to override this
* method to modify the outgoing handshake response.
* the outgoing handshake response
*
* @param request the handshake request from the client
* @param response the handshake response formulated by the container.
*/
/**
* Called by the container after it has formulated a handshake response resulting from
* a well-formed handshake request. The container has already 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 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,
Collections.unmodifiableList(this.subprotocols),
Collections.unmodifiableList(this.extensions),
Collections.unmodifiableList(this.encoders),
Collections.unmodifiableList(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;
}
}
}