Code cleanups.

Added TODOs to remember the link between the HTTP2Connection
fill callback and HTTP2ConnectionFactory.reservedThreads.

jetty-http2/http2-client/src/main/java/org/eclipse/jetty/http2/client/HTTP2ClientConnectionFactory.java

@@ -47,7 +47,6 @@ public class HTTP2ClientConnectionFactory implements ClientConnectionFactory
     public static final String CLIENT_CONTEXT_KEY = "http2.client";
     public static final String BYTE_BUFFER_POOL_CONTEXT_KEY = "http2.client.byteBufferPool";
     public static final String EXECUTOR_CONTEXT_KEY = "http2.client.executor";
-    public static final String PREALLOCATED_EXECUTOR_CONTEXT_KEY = "http2.client.preallocatedExecutor";
     public static final String SCHEDULER_CONTEXT_KEY = "http2.client.scheduler";
     public static final String SESSION_LISTENER_CONTEXT_KEY = "http2.client.sessionListener";
     public static final String SESSION_PROMISE_CONTEXT_KEY = "http2.client.sessionPromise";
@@ -60,7 +59,6 @@ public class HTTP2ClientConnectionFactory implements ClientConnectionFactory
         HTTP2Client client = (HTTP2Client)context.get(CLIENT_CONTEXT_KEY);
         ByteBufferPool byteBufferPool = (ByteBufferPool)context.get(BYTE_BUFFER_POOL_CONTEXT_KEY);
         Executor executor = (Executor)context.get(EXECUTOR_CONTEXT_KEY);
-        ReservedThreadExecutor preallocatedExecutor = (ReservedThreadExecutor)context.get(PREALLOCATED_EXECUTOR_CONTEXT_KEY);
         Scheduler scheduler = (Scheduler)context.get(SCHEDULER_CONTEXT_KEY);
         Session.Listener listener = (Session.Listener)context.get(SESSION_LISTENER_CONTEXT_KEY);
         @SuppressWarnings("unchecked")
@@ -71,37 +69,29 @@ public class HTTP2ClientConnectionFactory implements ClientConnectionFactory
         HTTP2ClientSession session = new HTTP2ClientSession(scheduler, endPoint, generator, listener, flowControl);
         Parser parser = new Parser(byteBufferPool, session, 4096, 8192);
 
-        if (preallocatedExecutor==null)
+        ReservedThreadExecutor reservedExecutor = provideReservedThreadExecutor(client, executor);
-        {
-            // TODO move this to non lazy construction
-            preallocatedExecutor=client.getBean(ReservedThreadExecutor.class);
-            if (preallocatedExecutor==null)
-            {
-                synchronized (this)
-                {
-                    if (preallocatedExecutor==null)
-                    {
-                        try
-                        {
-                            preallocatedExecutor = new ReservedThreadExecutor(executor,1); // TODO configure size
-                            preallocatedExecutor.start();
-                            client.addBean(preallocatedExecutor,true);
-                        }
-                        catch (Exception e)
-                        {
-                            throw new RuntimeException(e);
-                        } 
-                    }
-                }
-            }
-        }
 
-        HTTP2ClientConnection connection = new HTTP2ClientConnection(client, byteBufferPool, preallocatedExecutor, endPoint,
+        HTTP2ClientConnection connection = new HTTP2ClientConnection(client, byteBufferPool, reservedExecutor, endPoint,
                 parser, session, client.getInputBufferSize(), promise, listener);
         connection.addListener(connectionListener);
         return customize(connection, context);
     }
 
+    protected ReservedThreadExecutor provideReservedThreadExecutor(HTTP2Client client, Executor executor)
+    {
+        synchronized (this)
+        {
+            ReservedThreadExecutor reservedExecutor = client.getBean(ReservedThreadExecutor.class);
+            if (reservedExecutor == null)
+            {
+                // TODO: see HTTP2Connection.FillableCallback
+                reservedExecutor = new ReservedThreadExecutor(executor, 0);
+                client.addManaged(reservedExecutor);
+            }
+            return reservedExecutor;
+        }
+    }
+
     private class HTTP2ClientConnection extends HTTP2Connection implements Callback
     {
         private final HTTP2Client client;

jetty-http2/http2-common/src/main/java/org/eclipse/jetty/http2/HTTP2Connection.java

@@ -58,7 +58,6 @@ public class HTTP2Connection extends AbstractConnection
         this.session = session;
         this.bufferSize = bufferSize;
         this.strategy = new EatWhatYouKill(producer, executor.getExecutor(), executor);
-        
         LifeCycle.start(strategy);
     }
 
@@ -274,6 +273,8 @@ public class HTTP2Connection extends AbstractConnection
         @Override
         public InvocationType getInvocationType()
         {
+            // TODO: see also AbstractHTTP2ServerConnectionFactory.reservedThreads.
+            // TODO: it's non blocking here because reservedThreads=0.
             return InvocationType.NON_BLOCKING;
         }
     }

jetty-http2/http2-server/src/main/java/org/eclipse/jetty/http2/server/AbstractHTTP2ServerConnectionFactory.java

@@ -154,6 +154,7 @@ public abstract class AbstractHTTP2ServerConnectionFactory extends AbstractConne
 
     public void setReservedThreads(int threads)
     {
+        // TODO: see also HTTP2Connection.FillableCallback.
         // TODO: currently disabled since the only value that works is 0.
 //        this.reservedThreads = threads;
     }
@@ -183,28 +184,7 @@ public abstract class AbstractHTTP2ServerConnectionFactory extends AbstractConne
         session.setStreamIdleTimeout(streamIdleTimeout);
         session.setInitialSessionRecvWindow(getInitialSessionRecvWindow());
 
-        ReservedThreadExecutor executor = connector.getBean(ReservedThreadExecutor.class);
+        ReservedThreadExecutor executor = provideReservedThreadExecutor(connector);
-        if (executor==null)
-        {
-            synchronized (this)
-            {
-                executor = connector.getBean(ReservedThreadExecutor.class);
-                if (executor==null)
-                {
-
-                    try
-                    {
-                        executor = new ReservedThreadExecutor(connector.getExecutor(), getReservedThreads());
-                        executor.start();
-                        connector.addBean(executor,true);
-                    }
-                    catch (Exception e)
-                    {   
-                        throw new RuntimeException(e);
-                    }
-                }
-            }
-        }
         
         ServerParser parser = newServerParser(connector, session);
         HTTP2Connection connection = new HTTP2ServerConnection(connector.getByteBufferPool(), executor,
@@ -213,6 +193,20 @@ public abstract class AbstractHTTP2ServerConnectionFactory extends AbstractConne
         return configure(connection, connector, endPoint);
     }
 
+    protected ReservedThreadExecutor provideReservedThreadExecutor(Connector connector)
+    {
+        synchronized (this)
+        {
+            ReservedThreadExecutor executor = getBean(ReservedThreadExecutor.class);
+            if (executor == null)
+            {
+                executor = new ReservedThreadExecutor(connector.getExecutor(), getReservedThreads());
+                addManaged(executor);
+            }
+            return executor;
+        }
+    }
+
     protected abstract ServerSessionListener newSessionListener(Connector connector, EndPoint endPoint);
 
     protected ServerParser newServerParser(Connector connector, ServerParser.Listener listener)