jdk/src/java.httpclient/share/classes/java/net/http/WSSignalHandler.java
changeset 42483 3850c235c3fb
parent 42482 15297dde0d55
parent 42479 a80dbf731cbe
child 42489 a9e4de33da2e
--- a/jdk/src/java.httpclient/share/classes/java/net/http/WSSignalHandler.java	Thu Dec 08 21:22:02 2016 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,138 +0,0 @@
-/*
- * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.  Oracle designates this
- * particular file as subject to the "Classpath" exception as provided
- * by Oracle in the LICENSE file that accompanied this code.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-package java.net.http;
-
-import java.util.concurrent.Executor;
-import java.util.concurrent.RejectedExecutionException;
-import java.util.concurrent.atomic.AtomicInteger;
-
-import static java.util.Objects.requireNonNull;
-
-//
-// The problem:
-// ------------
-//   1. For every invocation of 'signal()' there must be at least
-//      1 invocation of 'handler.run()' that goes after
-//   2. There must be no more than 1 thread running the 'handler.run()'
-//      at any given time
-//
-// For example, imagine each signal increments (+1) some number. Then the
-// handler responds (eventually) the way that makes the number 0.
-//
-// For each signal there's a response. Several signals may be handled by a
-// single response.
-//
-final class WSSignalHandler {
-
-    // In this state the task is neither submitted nor running.
-    // No one is handling signals. If a new signal has been received, the task
-    // has to be submitted to the executor in order to handle this signal.
-    private static final int DONE    = 0;
-
-    // In this state the task is running.
-    // * If the signaller has found the task in this state it will try to change
-    //   the state to RERUN in order to make the already running task to handle
-    //   the new signal before exiting.
-    // * If the task has found itself in this state it will exit.
-    private static final int RUNNING = 1;
-
-    // A signal to the task, that it must rerun on the spot (without being
-    // resubmitted to the executor).
-    // If the task has found itself in this state it resets the state to
-    // RUNNING and repeats the pass.
-    private static final int RERUN   = 2;
-
-    private final AtomicInteger state = new AtomicInteger(DONE);
-
-    private final Executor executor;
-    private final Runnable task;
-
-    WSSignalHandler(Executor executor, Runnable handler) {
-        this.executor = requireNonNull(executor);
-        requireNonNull(handler);
-
-        task = () -> {
-            while (!Thread.currentThread().isInterrupted()) {
-
-                try {
-                    handler.run();
-                } catch (Exception e) {
-                    // Sorry, the task won't be automatically retried;
-                    // hope next signals (if any) will kick off the handling
-                    state.set(DONE);
-                    throw e;
-                }
-
-                int prev = state.getAndUpdate(s -> {
-                    if (s == RUNNING) {
-                        return DONE;
-                    } else {
-                        return RUNNING;
-                    }
-                });
-
-                // Can't be DONE, since only the task itself may transit state
-                // into DONE (with one exception: RejectedExecution in signal();
-                // but in that case we couldn't be here at all)
-                assert prev == RUNNING || prev == RERUN;
-
-                if (prev == RUNNING) {
-                    break;
-                }
-            }
-        };
-    }
-
-    // Invoked by outer code to signal
-    void signal() {
-
-        int prev = state.getAndUpdate(s -> {
-            switch (s) {
-                case RUNNING:
-                    return RERUN;
-                case DONE:
-                    return RUNNING;
-                case RERUN:
-                    return RERUN;
-                default:
-                    throw new InternalError(String.valueOf(s));
-            }
-        });
-
-        if (prev != DONE) {
-            // Nothing to do! piggybacking on previous signal
-            return;
-        }
-        try {
-            executor.execute(task);
-        } catch (RejectedExecutionException e) {
-            // Sorry some signal() invocations may have been accepted, but won't
-            // be done, since the 'task' couldn't be submitted
-            state.set(DONE);
-            throw e;
-        }
-    }
-}