cleanups in Jetty WS API

Signed-off-by: Lachlan Roberts <lachlan@webtide.com>

jetty-websocket/websocket-jetty-api/src/main/java/module-info.java

@@ -23,7 +23,6 @@ module org.eclipse.jetty.websocket.jetty.api
     exports org.eclipse.jetty.websocket.api;
     exports org.eclipse.jetty.websocket.api.annotations;
     exports org.eclipse.jetty.websocket.api.exceptions;
-    exports org.eclipse.jetty.websocket.api.extensions;
     exports org.eclipse.jetty.websocket.api.util;
 
     uses ExtensionConfig.Parser;

jetty-websocket/websocket-jetty-api/src/main/java/org/eclipse/jetty/websocket/api/CloseStatus.java

@@ -23,8 +23,8 @@ public class CloseStatus
     private static final int MAX_CONTROL_PAYLOAD = 125;
     public static final int MAX_REASON_PHRASE = MAX_CONTROL_PAYLOAD - 2;
 
-    private int code;
-    private String phrase;
+    private final int code;
+    private final String phrase;
 
     /**
      * Creates a reason for closing a web socket connection with the given code and reason phrase.

jetty-websocket/websocket-jetty-api/src/main/java/org/eclipse/jetty/websocket/api/Frame.java

@@ -46,7 +46,7 @@ public interface Frame
             throw new IllegalArgumentException("OpCode " + op + " is not a valid Frame.Type");
         }
 
-        private byte opcode;
+        private final byte opcode;
 
         Type(byte code)
         {

jetty-websocket/websocket-jetty-api/src/main/java/org/eclipse/jetty/websocket/api/WebSocketAdapter.java

@@ -39,14 +39,12 @@ public class WebSocketAdapter implements WebSocketListener
 
     public boolean isConnected()
     {
-        Session sess = this.session;
-        return (sess != null) && (sess.isOpen());
+        return session.isOpen();
     }
 
     public boolean isNotConnected()
     {
-        Session sess = this.session;
-        return (sess == null) || (!sess.isOpen());
+        return !isConnected();
     }
 
     @Override

jetty-websocket/websocket-jetty-api/src/main/java/org/eclipse/jetty/websocket/api/exceptions/CloseException.java

@@ -21,7 +21,7 @@ package org.eclipse.jetty.websocket.api.exceptions;
 @SuppressWarnings("serial")
 public class CloseException extends WebSocketException
 {
-    private int statusCode;
+    private final int statusCode;
 
     public CloseException(int closeCode, String message)
     {

jetty-websocket/websocket-jetty-api/src/main/java/org/eclipse/jetty/websocket/api/util/WebSocketConstants.java

@@ -16,7 +16,7 @@
 // ========================================================================
 //
 
-package org.eclipse.jetty.websocket.api;
+package org.eclipse.jetty.websocket.api.util;
 
 public final class WebSocketConstants
 {