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Wishful fix for NETTY-115 AccessControlException when running Netty from an Applet

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* AtomicReferenceFieldUpdater is used only when it's permitted to be used.
This commit is contained in:
Trustin Lee 2009-02-03 11:15:25 +00:00
parent a0e2c470b7
commit 67d90615e1
1 changed files with 33 additions and 4 deletions
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37
src/main/java/org/jboss/netty/util/LinkedTransferQueue.java
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@ -136,12 +136,41 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E> implements Blocking
this.isData = isData;
}
private static final AtomicReferenceFieldUpdater<QNode, QNode>
nextUpdater = AtomicReferenceFieldUpdater.newUpdater
(QNode.class, QNode.class, "next");
private static final AtomicReferenceFieldUpdater<QNode, QNode> nextUpdater;
static {
AtomicReferenceFieldUpdater<QNode, QNode> tmp = null;
try {
tmp = AtomicReferenceFieldUpdater.newUpdater(
QNode.class, QNode.class, "next");
// Test if AtomicReferenceFieldUpdater is really working.
QNode testNode = new QNode(null, false);
tmp.set(testNode, testNode);
if (testNode.next != testNode) {
// Not set as expected - fall back to the safe mode.
throw new Exception();
}
} catch (Throwable t) {
// Running in a restricted environment with a security manager.
tmp = null;
}
nextUpdater = tmp;
}
boolean casNext(QNode cmp, QNode val) {
return nextUpdater.compareAndSet(this, cmp, val);
if (nextUpdater == null) {
// Safe mode.
synchronized (this) {
if (next == cmp) {
next = val;
return true;
} else {
return false;
}
}
} else {
return nextUpdater.compareAndSet(this, cmp, val);
}
}
}