| 12 |
|
import java.security.PrivilegedAction; |
| 13 |
|
|
| 14 |
|
/** |
| 15 |
< |
* A {@link FutureTask} that executes with the given (or current, if |
| 16 |
< |
* not specified) access control context and/or the given (or current) |
| 17 |
< |
* context class loader. |
| 15 |
> |
* A {@link FutureTask} that executes, if allowed, with the current |
| 16 |
> |
* access control context and context class loader of the thread |
| 17 |
> |
* creating the task. A new <tt>PrivilegedFutureTask</tt> |
| 18 |
> |
* can be created within an {@link AccessController#doPrivileged} |
| 19 |
> |
* action to run tasks under the selected permission settings |
| 20 |
> |
* holding within that action. |
| 21 |
> |
* @see Executors |
| 22 |
|
* |
| 23 |
|
* @since 1.5 |
| 24 |
|
* @author Doug Lea |
| 25 |
|
*/ |
| 26 |
|
public class PrivilegedFutureTask<T> extends FutureTask<T> { |
| 27 |
+ |
private final ClassLoader ccl; |
| 28 |
+ |
private final AccessControlContext acc; |
| 29 |
|
|
| 30 |
|
/** |
| 31 |
|
* Constructs a <tt>PrivilegedFutureTask</tt> that will, upon running, |
| 40 |
|
super(task); |
| 41 |
|
this.ccl = Thread.currentThread().getContextClassLoader(); |
| 42 |
|
this.acc = AccessController.getContext(); |
| 37 |
– |
|
| 43 |
|
acc.checkPermission(new RuntimePermission("getContextClassLoader")); |
| 44 |
|
acc.checkPermission(new RuntimePermission("setContextClassLoader")); |
| 45 |
|
} |
| 46 |
|
|
| 47 |
< |
|
| 47 |
> |
/** |
| 48 |
> |
* Executes within the established access control and context |
| 49 |
> |
* class loader if possible, else causes invocations of {@link |
| 50 |
> |
* Future#get} to receive the associated AccessControlException. |
| 51 |
> |
*/ |
| 52 |
|
public void run() { |
| 53 |
< |
AccessController.doPrivileged(new PrivilegedAction() { |
| 54 |
< |
public Object run() { |
| 55 |
< |
runPrivileged(); |
| 56 |
< |
return null; |
| 57 |
< |
} |
| 49 |
< |
}, acc); |
| 53 |
> |
try { |
| 54 |
> |
AccessController.doPrivileged(new PrivilegedFutureAction(), acc); |
| 55 |
> |
} catch(Throwable ex) { |
| 56 |
> |
setException(ex); |
| 57 |
> |
} |
| 58 |
|
} |
| 59 |
|
|
| 60 |
< |
|
| 61 |
< |
private void runPrivileged() { |
| 62 |
< |
ClassLoader saved = null; |
| 63 |
< |
try { |
| 64 |
< |
ClassLoader current = Thread.currentThread().getContextClassLoader(); |
| 65 |
< |
if (ccl != current) { |
| 66 |
< |
Thread.currentThread().setContextClassLoader(ccl); |
| 67 |
< |
saved = current; |
| 68 |
< |
} |
| 69 |
< |
super.run(); |
| 70 |
< |
} |
| 71 |
< |
finally { |
| 72 |
< |
if (saved != null) |
| 73 |
< |
Thread.currentThread().setContextClassLoader(saved); |
| 74 |
< |
} |
| 60 |
> |
private class PrivilegedFutureAction implements PrivilegedAction { |
| 61 |
> |
public Object run() { |
| 62 |
> |
ClassLoader saved = null; |
| 63 |
> |
try { |
| 64 |
> |
ClassLoader current = Thread.currentThread().getContextClassLoader(); |
| 65 |
> |
if (ccl != current) { |
| 66 |
> |
Thread.currentThread().setContextClassLoader(ccl); |
| 67 |
> |
saved = current; |
| 68 |
> |
} |
| 69 |
> |
PrivilegedFutureTask.super.run(); |
| 70 |
> |
return null; |
| 71 |
> |
} finally { |
| 72 |
> |
if (saved != null) |
| 73 |
> |
Thread.currentThread().setContextClassLoader(saved); |
| 74 |
> |
} |
| 75 |
> |
} |
| 76 |
|
} |
| 68 |
– |
|
| 69 |
– |
private final ClassLoader ccl; |
| 70 |
– |
private final AccessControlContext acc; |
| 77 |
|
} |
| 72 |
– |
|
