java.security
$B%/%i%9(J AccessController

java.lang.Object
  |
  +--java.security.AccessController

public final class AccessController

extends Object

AccessController $B%/%i%9$O!"%"%/%;%9@)8f$NA`:n$H7hDj$K;HMQ$5$l$^$9!#(J

$B6qBNE*$K$O!"(JAccessController $B%/%i%9$r

$B8=:_M-8z$J%;%-%e%j%F%#%]%j%7!<$K4p$E$$$F!"=EMW$J%7%9%F%`%j%=!<%9$X$N%"%/%;%9$,5v2D$5$l$k$+!"5qH]$5$l$k$+$r7hDj$9$k(J

$B%3!<%I$r!VFC8"!W$,M?$($i$l$?$b$N$H$7$F%^!<%/$7!"0J9_$N%"%/%;%9$N7hDj$K1F6A$rM?$($k(J

$B%"%/%;%9@)8f$,J]B8$7$?%3%s%F%-%9%H$K4X$7$FMQ0U$5$l$kJL$N%3%s%F%-%9%H$+$i7hDj$G$-$k$h$&$K!"8=:_$N8F$S=P$7B&%3%s%F%-%9%H$N!V%9%J%C%W%7%g%C%H!W$r

checkPermission $B%a%=%C%I$O!";XDj$7$?%"%/%;%98"$K$h$C$F<($5$l$k%"%/%;%9MW5a$,5v2D$5$l$k$+!"5qH]$5$l$k$+$r7hDj$7$^$9!#0J2<$K!"8F$S=P$7$NNc$r<($7$^$9!#$3$NNc$G$O!"(JcheckPermission $B$O!"(J/temp $B%G%#%l%/%H%j$N(J testFile $B$H$$$&%U%!%$%k$X$NFI$_9~$_8"$r5v2D$9$k$+$I$&$+$r7hDj$7$^$9!#(J

 
    FilePermission perm = new FilePermission("/temp/testFile", "read");
    AccessController.checkPermission(perm);
 
 

$BMW5a$7$?%"%/%;%9$,5v2D$5$l$k>l9g$K$O!"(JcheckPermission $B$O2?$b$7$J$$$GI|5"$7$^$9!#5qH]$5$l$k>l9g$K$O!"(JAccessControlException $B$,%9%m!<$5$l$^$9!#MW5a%"%/%;%98"$,ITE,@Z$G$"$C$?$j!"L58z$JCM$r4^$s$G$$$?>l9g$K$b!"(JAccessControlException $B$O%9%m!<$5$l$k$3$H$,$"$j$^$9!#$=$&$7$?>pJs$O!"2DG=$J>l9g$K$OI,$:Ds6!$5$l$^$9!#(J $B8=:_$N%9%l%C%I$,!"(Jm $B8D$N8F$S=P$7B&$r(J 1$B!"(J2 (I% (I% (I% m $B$N=gHV$G=hM}$7!"8F$S=P$7B&(J m $B$,(J checkPermission $B%a%=%C%I$r8F$S=P$7$?$H$7$^$9!#(JcheckPermission $B%a%=%C%I$O i = m; while (i > 0) { if ($B8F$S=P$7B&$N%I%a%$%s$K%"%/%;%98"$,$J$$(J) throw AccessControlException else if ($B8F$S=P$785(J i $B$,FC8"%3!<%I$H$7$F%^!<%/$5$l$F$$$k(J) { if ($B%3%s%F%-%9%H$,(J doPrivileged $B$N8F$S=P$7$G;XDj$5$l$?(J) context.checkPermission(permission) return; } i = i - 1; }; // Next, check the context inherited when // the thread was created. Whenever a new thread is created, the // AccessControlContext at that time is // stored and associated with the new thread, as the "inherited" // context. inheritedContext.checkPermission(permission);

$B8F$S=P$7B&$O!"FC8"%3!<%I$H$7$F%^!<%/$G$-$^$9(J (doPrivileged $B$*$h$S0J2<$N@bL@$r;2>H(J)$B!#%"%/%;%9@)8f$r7hDj$9$k>l9g!"(JcheckPermission $B%a%=%C%I$O!"%3%s%F%-%9%H0z?t$N$J$$(J doPrivileged $B$N8F$S=P$7$K$h$C$FFC8"%3!<%I$H$7$F%^!<%/$5$l$?8F$S=P$7B&$KFO$$$?$H$-$K!"8!::$rCf;_$7$^$9(J ($B%3%s%F%-%9%H0z?t$K$D$$$F$O!"0J2<$N@bL@$r;2>H(J)$B!#$=$N8F$S=P$7B&$NNN0h$K;XDj$5$l$?%"%/%;%98"$,$"$k>l9g!"0J8e$N8!::$O9T$o$l$:!"(JcheckPermission $B$O2?$b$7$J$$$GI|5"$7$F!"MW5a$7$?%"%/%;%9$,5v2D$5$l$?$3$H$r<($7$^$9!#$=$NNN0h$K;XDj$5$l$?%"%/%;%98"$,$J$$>l9g$K$O!"DL>o$I$*$jNc30$,%9%m!<$5$l$^$9!#(J

$B0J2<$K!"FC8"5!G=$NDL>o$N;H$$J}$r@bL@$7$^$9!#FC8"%V%m%C%/Fb$+$iCM$rJV$9I,MW$,$J$$>l9g$K$O!" somemethod() { ...normal code here... AccessController.doPrivileged(new PrivilegedAction() { public Object run() { // privileged code goes here, for example: System.loadLibrary("awt"); return null; // nothing to return } }); ...normal code here... }

PrivilegedAction $B$O!"(JObject $B$rJV$9(J run $B$H$$$&%a%=%C%I$r;}$D%$%s%?%U%'!<%9$G$9!#>e5-$NNc$O!"$=$N%$%s%?%U%'!<%9$Nrun $B%a%=%C%I$N8GDjdoPrivileged $B$,8F$S=P$5$l$k$H!"$=$N(J doPrivileged $B$K(J PrivilegedAction $B$NdoPrivileged $B%a%=%C%I$O!"FC8"$rM-8z$K$7$?$"$H$G(J PrivilegedAction $B$Nrun $B%a%=%C%I$r8F$S=P$7!"(Jrun $B%a%=%C%I$NLa$jCM$r(J doPrivileged $B$NLa$jCM(J ($B>e5-$NNc$G$OL5;k$5$l$F$$$k(J) $B$H$7$FJV$7$^$9!#(J

$BCM$rJV$9I,MW$,$"$k>l9g$K$O!" somemethod() { ...normal code here... String user = (String) AccessController.doPrivileged( new PrivilegedAction() { public Object run() { return System.getProperty("user.name"); } } ); ...normal code here... }

run $B%a%=%C%I$Gthrows $B@a$KI=<($5$l$F$$$kNc30(J) $B$r%9%m!<$9$k2DG=@-$,$"$k>l9g$K$O!"(JPrivilegedAction $B%$%s%?%U%'!<%9$NBe$o$j$K(J PrivilegedExceptionAction $B%$%s%?%U%'!<%9$r;HMQ$9$kI,MW$,$"$j$^$9!#(J

   somemethod() throws FileNotFoundException {
        ...normal code here...
      try {
        FileInputStream fis = (FileInputStream) AccessController.doPrivileged(
          new PrivilegedExceptionAction() {
            public Object run() throws FileNotFoundException {
                return new FileInputStream("someFile");
            }
          }
        );
      } catch (PrivilegedActionException e) {
        // e.getException() should be an instance of FileNotFoundException,
        // as only "checked" exceptions will be "wrapped" in a
        // PrivilegedActionException.
        throw (FileNotFoundException) e.getException();
      }
        ...normal code here...
  }
 

$BFC8"9=B$$N;HMQ$K$O:Y?4$NCm0U$rJ'$C$F!"FC8"%3!<%I%;%/%7%g%s$r$G$-$k$@$1>.$5$/$7$F$/$@$5$$!#(J

checkPermission $B$O!">o$K8=:_l9g$b$"$j$^$9!#$3$N>u67$KBP1~$9$k$?$a$K!"(JgetContext $B%a%=%C%I$H(J AccessControlContext $B%/%i%9$,Ds6!$5$l$F$$$^$9!#(JgetContext $B%a%=%C%I$O!"8=:_$N8F$S=P$7B&%3%s%F%-%9%H$N!V%9%J%C%W%7%g%C%H!W$r AccessControlContext acc = AccessController.getContext()

AccessControlContext $B$K$O!"8=:_checkPermission $B%a%=%C%I$,$"$j$^$9!#$7$?$,$C$F!"JL$N%3%s%F%-%9%HFb$N%3!<%I$O!"0JA0$KJ]B8$7$?(J AccessControlContext $B%*%V%8%'%/%H$N(J checkPermission $B%a%=%C%I$r8F$S=P$9$3$H$,$G$-$^$9!#0J2<$K!"8F$S=P$7$NNc$r<($7$^$9!#(J

 
   acc.checkPermission(permission)
 
 

$B$^$?!"%3%s%F%-%9%H$r$I$N%"%/%;%98"$G8!::$9$k$+$,!";vA0$K$OITL@$J>l9g$,$"$j$^$9!#$3$&$7$?>l9g$K$O!"%3%s%F%-%9%H$rCM$H$7$F$H$k(J doPrivileged $B%a%=%C%I$r;HMQ$G$-$^$9!#(J

   somemethod() {
         AccessController.doPrivileged(new PrivilegedAction() {
              public Object run() {
                 // Code goes here. Any permission checks within this
                 // run method will require that the intersection of the
                 // callers protection domain and the snapshot's
                 // context have the desired permission.
              }
         }, acc);
         ...normal code here...
   }
 

$B4XO"9`L\(J:

AccessControlContext

$B%a%=%C%I$N35MW(J

static void	checkPermission(Permission perm) $B8=:_M-8z$J%;%-%e%j%F%#%]%j%7!<$K4p$E$$$F!";XDj$5$l$?%"%/%;%98"$K$h$C$F<($5$l$k%"%/%;%9MW5a$,5v2D$5$l$k$+!"5qH]$5$l$k$+$r7hDj$7$^$9!#(J
static Object	doPrivileged(PrivilegedAction action) $BM-8z$K$J$C$?FC8"$r;H$C$F!";XDj$5$l$?(J PrivilegedAction $B$r
static Object	doPrivileged(PrivilegedAction action, AccessControlContext context) $B;XDj$5$l$?(J AccessControlContext $B$K$h$C$FM-8z$K$J$j!"$+$D@)8B$5$l$kFC8"$r;H$C$F!";XDj$5$l$?(J PrivilegedAction $B$r
static Object	doPrivileged(PrivilegedExceptionAction action) $BM-8z$K$J$C$?FC8"$r;H$C$F!";XDj$5$l$?(J PrivilegedExceptionAction $B$r
static Object	doPrivileged(PrivilegedExceptionAction action, AccessControlContext context) $B;XDj$5$l$?(J AccessControlContext $B$K$h$C$FM-8z$K$J$j!"$+$D@)8B$5$l$kFC8"$r;H$C$F!";XDj$5$l$?(J PrivilegedExceptionAction $B$r
static AccessControlContext	getContext() $B8=:_$N%9%l%C%I$N7Q>5$5$l$?(J AccessControlContext $B$r4^$`!"8=:_$N8F$S=P$7B&%3%s%F%-%9%H$N!V%9%J%C%W%7%g%C%H!W$r

$B%/%i%9(J java.lang.Object $B$+$i7Q>5$7$?%a%=%C%I(J

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

$B%a%=%C%I$N>\:Y(J

doPrivileged

public static Object doPrivileged(PrivilegedAction action)

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$B%Q%i%a!<%?(J:

action - $B$BLa$jCM(J:

$B%"%/%7%g%s$N(J run $B%a%=%C%I$K$h$C$FJV$5$l$kCM(J

$B4XO"9`L\(J:

doPrivileged(PrivilegedAction,AccessControlContext), doPrivileged(PrivilegedExceptionAction)

doPrivileged

public static Object doPrivileged(PrivilegedAction action,
                                  AccessControlContext context)

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$B%Q%i%a!<%?(J:

action - $Bcontext - $B;XDj$5$l$?%"%/%7%g%s$N$BLa$jCM(J:

$B%"%/%7%g%s$N(J run $B%a%=%C%I$K$h$C$FJV$5$l$kCM(J

$B4XO"9`L\(J:

doPrivileged(PrivilegedAction), doPrivileged(PrivilegedExceptionAction,AccessControlContext)

doPrivileged

public static Object doPrivileged(PrivilegedExceptionAction action)
                           throws PrivilegedActionException

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$B%Q%i%a!<%?(J:

action - $B$BLa$jCM(J:

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$BNc30(J:

PrivilegedActionException - $B;XDj$5$l$?%"%/%7%g%s$N(J run $B%a%=%C%I$,!V3NG':Q!W$NNc30$r%9%m!<$7$?>l9g(J

$B4XO"9`L\(J:

doPrivileged(PrivilegedAction), doPrivileged(PrivilegedExceptionAction,AccessControlContext)

doPrivileged

public static Object doPrivileged(PrivilegedExceptionAction action,
                                  AccessControlContext context)
                           throws PrivilegedActionException

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$B%Q%i%a!<%?(J:

action - $Bcontext - $B;XDj$5$l$?%"%/%7%g%s$N$BLa$jCM(J:

$B%"%/%7%g%s$N(J run $B%a%=%C%I$K$h$C$FJV$5$l$kCM(J

$BNc30(J:

PrivilegedActionException - $B;XDj$5$l$?%"%/%7%g%s$N(J run $B%a%=%C%I$,!V3NG':Q!W$NNc30$r%9%m!<$7$?>l9g(J

$B4XO"9`L\(J:

doPrivileged(PrivilegedAction), doPrivileged(PrivilegedExceptionAction,AccessControlContext)

getContext

public static AccessControlContext getContext()

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$BLa$jCM(J:

$B8=:_$N%3%s%F%-%9%H$K4p$E$/(J AccessControlContext

$B4XO"9`L\(J:

AccessControlContext

checkPermission

public static void checkPermission(Permission perm)
                            throws AccessControlException

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$B%Q%i%a!<%?(J:

perm - $BMW5a%"%/%;%98"(J

$BNc30(J:

AccessControlException - $B8=:_$N%;%-%e%j%F%#%]%j%7!<$K4p$E$$$F!";XDj$5$l$?%"%/%;%98"$,5v2D$5$l$J$$>l9g(J