SubjectDelegator.java 文件源码

public AccessControlContext
    delegatedContext(AccessControlContext authenticatedACC,
                     Subject delegatedSubject,
                     boolean removeCallerContext)
        throws SecurityException {

    if (System.getSecurityManager() != null && authenticatedACC == null) {
        throw new SecurityException("Illegal AccessControlContext: null");
    }

    // Check if the subject delegation permission allows the
    // authenticated subject to assume the identity of each
    // principal in the delegated subject
    //
    Collection<Principal> ps = getSubjectPrincipals(delegatedSubject);
    final Collection<Permission> permissions = new ArrayList<>(ps.size());
    for(Principal p : ps) {
        final String pname = p.getClass().getName() + "." + p.getName();
        permissions.add(new SubjectDelegationPermission(pname));
    }
    PrivilegedAction<Void> action =
        new PrivilegedAction<Void>() {
            public Void run() {
                for (Permission sdp : permissions) {
                    AccessController.checkPermission(sdp);
                }
                return null;
            }
        };
    AccessController.doPrivileged(action, authenticatedACC);

    return getDelegatedAcc(delegatedSubject, removeCallerContext);
}