net.java.games.input.LinuxDeviceThread Maven / Gradle / Ivy
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/**
* Copyright (C) 2003 Jeremy Booth ([email protected])
*
* 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.
* The name of the author may not be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 net.java.games.input;
import java.io.IOException;
import java.util.List;
import java.util.ArrayList;
/**
* Linux doesn't have proper support for force feedback
* from different threads since it relies on PIDs
* to determine ownership of a particular effect slot.
* Therefore we have to hack around this by
* making sure everything related to FF
* (including the final device close that performs
* and implicit deletion of all the process' effects)
* is run on a single thread.
*/
final class LinuxDeviceThread extends Thread {
private final List tasks = new ArrayList();
public LinuxDeviceThread() {
setDaemon(true);
start();
}
public synchronized final void run() {
while (true) {
if (!tasks.isEmpty()) {
LinuxDeviceTask task = (LinuxDeviceTask)tasks.remove(0);
task.doExecute();
synchronized (task) {
task.notify();
}
} else {
try {
wait();
} catch (InterruptedException e) {
// ignore
}
}
}
}
public final Object execute(LinuxDeviceTask task) throws IOException {
synchronized (this) {
tasks.add(task);
notify();
}
synchronized (task) {
while (task.getState() == LinuxDeviceTask.INPROGRESS) {
try {
task.wait();
} catch (InterruptedException e) {
// ignore
}
}
}
switch (task.getState()) {
case LinuxDeviceTask.COMPLETED:
return task.getResult();
case LinuxDeviceTask.FAILED:
throw task.getException();
default:
throw new RuntimeException("Invalid task state: " + task.getState());
}
}
}