// ==================== Program Discription ==========================
// 程序名稱：示例20-4 : MyPrivilegedAction.java
// 程序目的：程序性授權
// ==============================================================
import java.io.*;
import java.security.*;
import javax.security.auth.*;
import javax.security.auth.login.*;
import java.util.*;
import com.sun.enterprise.security.*;

public class MyPrivilegedAction implements PrivilegedAction
{
    public Object run() {
       // Get the passed in subject from the DoAs
       AccessControlContext context = AccessController.getContext();
       Subject subject = Subject.getSubject( context );
       if (subject == null ) {
         throw new AccessControlException("Denied");
       }

       // Iterate through the principal set looking for sa
       Set principals = subject.getPrincipals();
       Iterator iterator = principals.iterator();
       while (iterator.hasNext()) {
         PrincipalImpl principal = (PrincipalImpl)iterator.next();
         if (principal.getName().equals( "sa" )) {
           System.out.println("sa has Payroll access\n");
           return new Integer(0);
         }
       }
       throw new AccessControlException("Denied");
   }
}