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Diffstat (limited to 'src/com/isode')
-rw-r--r-- | src/com/isode/stroke/eventloop/SingleThreadedEventLoop.java | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/src/com/isode/stroke/eventloop/SingleThreadedEventLoop.java b/src/com/isode/stroke/eventloop/SingleThreadedEventLoop.java new file mode 100644 index 0000000..bf32b3c --- /dev/null +++ b/src/com/isode/stroke/eventloop/SingleThreadedEventLoop.java @@ -0,0 +1,108 @@ +/* + * Copyright (c) 2010 Soren Dreijer + * Licensed under the simplified BSD license. + * See Documentation/Licenses/BSD-simplified.txt for more information. + */ +/* + * Copyright (c) 2015 Tarun Gupta. + * Licensed under the simplified BSD license. + * See Documentation/Licenses/BSD-simplified.txt for more information. + */ + +package com.isode.stroke.eventloop; + +import com.isode.stroke.eventloop.EventLoop; +import java.util.Vector; +import java.util.Collection; +import java.util.ArrayList; + +// DESCRIPTION: +// +// All interaction with Swiften should happen on the same thread, such as the main GUI thread, +// since the library isn't thread-safe. +// For applications that don't have a main loop, such as WPF and MFC applications, we need a +// different approach to process events from Swiften. +// +// The SingleThreadedEventLoop class implements an event loop that can be used from such applications. +// +// USAGE: +// +// Spawn a new thread in the desired framework and call SingleThreadedEventLoop::waitForEvents(). The method +// blocks until a new event has arrived at which time it'll return, or until the wait is canceled +// at which time it throws EventLoopCanceledException. +// +// When a new event has arrived and SingleThreadedEventLoop::waitForEvents() returns, the caller should then +// call SingleThreadedEventLoop::handleEvents() on the main GUI thread. For WPF applications, for instance, +// the Dispatcher class can be used to execute the call on the GUI thread. +// +public class SingleThreadedEventLoop extends EventLoop { + + public class EventLoopCanceledException extends Exception { + public EventLoopCanceledException(String message) { + super(message); + } + } + + private boolean shouldShutDown_; + private Vector<Event> events_ = new Vector<Event>(); + private Object eventsMutex_ = new Object(); + + public SingleThreadedEventLoop() { + shouldShutDown_ = false; + } + + /** + * Blocks while waiting for new events and returns when new events are available. + * @throws EventLoopCanceledException when the wait is canceled. + */ + public void waitForEvents() throws EventLoopCanceledException { + synchronized(eventsMutex_) { + while (events_.isEmpty() && !shouldShutDown_) { + try { + eventsMutex_.wait(); + } catch (InterruptedException e) { + + } + } + } + if (shouldShutDown_) { + throw new EventLoopCanceledException(""); + } + } + + public void handleEvents() { + // Make a copy of the list of events so we don't block any threads that post + // events while we process them. + Vector<Event> events = new Vector<Event>(); + synchronized(eventsMutex_) { + swapCollectionContents(events, events_); + } + + // Loop through all the events and handle them + for(Event event : events) { + handleEvent(event); + } + } + + static <T> void swapCollectionContents(Collection<T> coll1, Collection<T> coll2) { + Collection<T> temp = new ArrayList<T>(coll1); + coll1.clear(); + coll1.addAll(coll2); + coll2.clear(); + coll2.addAll(temp); + } + + public void stop() { + synchronized(eventsMutex_) { + shouldShutDown_ = true; + eventsMutex_.notifyAll(); + } + } + + public void post(final Event event) { + synchronized(eventsMutex_) { + events_.add(event); + eventsMutex_.notifyAll(); + } + } +}
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