| /* |
| * Copyright 2016, Google Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| package io.grpc.internal; |
| |
| import io.grpc.ConnectivityState; |
| |
| import java.util.ArrayList; |
| import java.util.concurrent.Executor; |
| |
| import javax.annotation.concurrent.NotThreadSafe; |
| |
| /** |
| * Book-keeps the connectivity state and callbacks. |
| */ |
| @NotThreadSafe |
| class ConnectivityStateManager { |
| private ArrayList<StateCallbackEntry> callbacks; |
| |
| private ConnectivityState state; |
| |
| ConnectivityStateManager(ConnectivityState initialState) { |
| state = initialState; |
| } |
| |
| void notifyWhenStateChanged(Runnable callback, Executor executor, ConnectivityState source) { |
| StateCallbackEntry callbackEntry = new StateCallbackEntry(callback, executor); |
| if (state != source) { |
| callbackEntry.runInExecutor(); |
| } else { |
| if (callbacks == null) { |
| callbacks = new ArrayList<StateCallbackEntry>(); |
| } |
| callbacks.add(callbackEntry); |
| } |
| } |
| |
| // TODO(zhangkun83): return a runnable in order to escape transport set lock, in case direct |
| // executor is used? |
| void gotoState(ConnectivityState newState) { |
| if (state != newState) { |
| if (state == ConnectivityState.SHUTDOWN) { |
| throw new IllegalStateException("Cannot transition out of SHUTDOWN to " + newState); |
| } |
| state = newState; |
| if (callbacks == null) { |
| return; |
| } |
| // Swap out callback list before calling them, because a callback may register new callbacks, |
| // if run in direct executor, can cause ConcurrentModificationException. |
| ArrayList<StateCallbackEntry> savedCallbacks = callbacks; |
| callbacks = null; |
| for (StateCallbackEntry callback : savedCallbacks) { |
| callback.runInExecutor(); |
| } |
| } |
| } |
| |
| ConnectivityState getState() { |
| return state; |
| } |
| |
| private static class StateCallbackEntry { |
| final Runnable callback; |
| final Executor executor; |
| |
| StateCallbackEntry(Runnable callback, Executor executor) { |
| this.callback = callback; |
| this.executor = executor; |
| } |
| |
| void runInExecutor() { |
| executor.execute(callback); |
| } |
| } |
| } |