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Description
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Jason writes:
What if cancel throws an exception? The
documentation does not list the possible SecurityException or the possible
RuntimeException/Error from done(). Should a subsequent cancel be allowed
to interrupt the runner if the first attempt was by a thread with out thread
modify permission?
Jason
//Test case for Future fun.
import java.util.concurrent.*;
import java.util.*;
public class Cancel implements Callable<Void> {
private final long sleep_ms;
public static void main(String[] args) {
cancelBeforeRun();
cancelAfterRun();
cancelCancelRun();
lateArrivingGet(false);
lateArrivingGet(true);
securityCancel(false);
securityCancel(true);
evilDone();
exit();
}
private static void cancelAfterRun() {
System.err.println("cancelAfterRun");
FutureTask task = new FutureTask(new Cancel(0L));
task.run();
testGoldenRule(task, false);
}
private static void cancelBeforeRun() {
System.err.println("cancelBeforeRun");
FutureTask task = new FutureTask(new Cancel(0L));
testGoldenRule(task, false);
}
private static void cancelCancelRun() {
System.err.println("cancelCancelRun");
FutureTask task = new FutureTask(new Cancel(0L));
task.cancel(false);
testGoldenRule(task, false);
}
private static void lateArrivingGet(boolean mi) {
System.err.println("lateArrivingGet("+ mi +')');
FutureTask task = new FutureTask(new Cancel(15 * 1000L)) {
public void run() {
super.run();
exit();
}
};
new Thread(task).start();
try {
Thread.sleep(1000L);
}
catch(InterruptedException IE) {
throw new AssertionError(IE);
}
testGoldenRule(task, mi);
}
private static void evilDone() {
System.err.println("evilDone");
FutureTask task = new FutureTask(new Cancel(15 * 1000L)) {
protected void done() {
if(super.isCancelled()) {
throw new InternalError();
}
}
};
testGoldenRule(task, false);
}
public static void securityCancel(boolean mi) {
FutureTask task = new FutureTask(new Cancel(15 * 1000L)) {
public void run() {
super.run();
exit();
}
};
new Thread(task).start();
try {
Thread.sleep(1000L);
}
catch(InterruptedException IE) {
throw new AssertionError(IE);
}
try {
System.setSecurityManager(new SecurityManager() {
public void checkAccess(Thread t) {
throw new SecurityException(t.toString());
}
});
testGoldenRule(task, mi);
}
finally {
System.setSecurityManager(null);
}
}
private static void testGoldenRule(Future task, boolean mi) {
try {
if(!task.cancel(mi)) {
try {
try {
task.get(0L, TimeUnit.NANOSECONDS);
throw new AssertionError("Get returned.");
}
catch(TimeoutException TE) {
if(task.isCancelled() && !task.isDone()) {
new AssertionError("Cancelled but not done.")
.initCause(TE).printStackTrace();
}
else {
task.get();
throw new AssertionError("Get returned.");
}
}
}
catch(InterruptedException IE) {
throw new AssertionError(IE);
}
catch(ExecutionException EE) {
EE.printStackTrace();
}
catch(CancellationException CE) {
new
AssertionError(CE.toString()).initCause(CE).printStackTrace();
}
}
else {
System.err.println("Pass (cancel was true).");
}
}
catch(SecurityException SE) {
SE.printStackTrace();
try {
testGoldenRule(task, mi);
}
catch(SecurityException again) {
System.err.println("Pass (failed twice).");
}
}
catch(InternalError IE) {
IE.printStackTrace();
testGoldenRule(task, mi);
}
}
private static void exit() {
System.err.println(new Date(System.currentTimeMillis()) +", "+
Thread.currentThread());
}
public Cancel(final long sleep_ms) {
this.sleep_ms = sleep_ms;
}
public Void call() throws Exception {
Thread.sleep(sleep_ms);
throw new Exception("Pass");
}
}
Posted Date : 2007-03-06 02:21:39.0
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