servicepermission.java

Mobile 应用程序使用 Java Micro Edition (Java ME) 平台

	if (action.equals("")) {
	    throw new IllegalArgumentException("action can't be empty");
	}

	int mask = NONE;

	char[] a = action.toCharArray();

	int i = a.length - 1;
	if (i < 0)
	    return mask;

	while (i != -1) {
	    char c;

	    // skip whitespace
	    while ((i!=-1) && ((c = a[i]) == ' ' ||
			       c == '\r' ||
			       c == '\n' ||
			       c == '\f' ||
			       c == '\t'))
		i--;

	    // check for the known strings
	    int matchlen;

	    if (i >= 7 && (a[i-7] == 'i' || a[i-7] == 'I') &&
			  (a[i-6] == 'n' || a[i-6] == 'N') &&
			  (a[i-5] == 'i' || a[i-5] == 'I') &&
			  (a[i-4] == 't' || a[i-4] == 'T') &&
			  (a[i-3] == 'i' || a[i-3] == 'I') &&
			  (a[i-2] == 'a' || a[i-2] == 'A') &&
			  (a[i-1] == 't' || a[i-1] == 'T') &&
			  (a[i] == 'e' || a[i] == 'E'))
	    {
		matchlen = 8;
		mask |= INITIATE;

	    } else if (i >= 5 && (a[i-5] == 'a' || a[i-5] == 'A') &&
				 (a[i-4] == 'c' || a[i-4] == 'C') &&
				 (a[i-3] == 'c' || a[i-3] == 'C') &&
				 (a[i-2] == 'e' || a[i-2] == 'E') &&
				 (a[i-1] == 'p' || a[i-1] == 'P') &&
				 (a[i] == 't' || a[i] == 'T'))
	    {
		matchlen = 6;
		mask |= ACCEPT;

	    } else {
		// parse error
		throw new IllegalArgumentException(
			"invalid permission: " + action);
	    }

	    // make sure we didn't just match the tail of a word
	    // like "ackbarfaccept".  Also, skip to the comma.
	    boolean seencomma = false;
	    while (i >= matchlen && !seencomma) {
		switch(a[i-matchlen]) {
		case ',':
		    seencomma = true;
		    /*FALLTHROUGH*/
		case ' ': case '\r': case '\n':
		case '\f': case '\t':
		    break;
		default:
		    throw new IllegalArgumentException(
			    "invalid permission: " + action);
		}
		i--;
	    }

	    // point i at the location of the comma minus one (or -1).
	    i -= matchlen;
	}

	return mask;
    }


    /**
     * WriteObject is called to save the state of the ServicePermission 
     * to a stream. The actions are serialized, and the superclass
     * takes care of the name.
     */
    private void writeObject(java.io.ObjectOutputStream s)
        throws IOException
    {
	// Write out the actions. The superclass takes care of the name
	// call getActions to make sure actions field is initialized
	if (actions == null)
	    getActions();
	s.defaultWriteObject();
    }

    /**
     * readObject is called to restore the state of the
     * ServicePermission from a stream.
     */
    private void readObject(java.io.ObjectInputStream s)
         throws IOException, ClassNotFoundException
    {
	// Read in the action, then initialize the rest
	s.defaultReadObject();
	init(getName(),getMask(actions));
    }


    /*
      public static void main(String args[]) throws Exception {
      ServicePermission this_ =
      new ServicePermission(args[0], "accept");
      ServicePermission that_ =
      new ServicePermission(args[1], "accept,initiate");
      System.out.println("-----\n");
      System.out.println("this.implies(that) = " + this_.implies(that_));
      System.out.println("-----\n");
      System.out.println("this = "+this_);
      System.out.println("-----\n");
      System.out.println("that = "+that_);
      System.out.println("-----\n");

      KrbServicePermissionCollection nps =
      new KrbServicePermissionCollection();
      nps.add(this_);
      nps.add(new ServicePermission("nfs/[e-mail]",
      "accept"));
      nps.add(new ServicePermission("host/[e-mail]",
      "initiate"));
      System.out.println("nps.implies(that) = " + nps.implies(that_));
      System.out.println("-----\n");

      Enumeration e = nps.elements();
	
      while (e.hasMoreElements()) {
      ServicePermission x =
      (ServicePermission) e.nextElement();
      System.out.println("nps.e = " + x);
      }

      }
    */
    
}


final class KrbServicePermissionCollection extends PermissionCollection 
    implements java.io.Serializable {

    // Not serialized; see serialization section at end of class
    private transient List perms;

    public KrbServicePermissionCollection() {
	perms = new ArrayList();
    }
    
    /**
     * Check and see if this collection of permissions implies the permissions 
     * expressed in "permission".
     *
     * @param p the Permission object to compare
     *
     * @return true if "permission" is a proper subset of a permission in 
     * the collection, false if not.
     */

    public boolean implies(Permission permission) {
	if (! (permission instanceof ServicePermission))
   		return false;

	ServicePermission np = (ServicePermission) permission;
	int desired = np.getMask();
	int effective = 0;
	int needed = desired;

	synchronized (this) {
	    int len = perms.size();
	
	    // need to deal with the case where the needed permission has
	    // more than one action and the collection has individual permissions
	    // that sum up to the needed.

	    for (int i = 0; i < len; i++) {
		ServicePermission x = (ServicePermission) perms.get(i);

		//System.out.println("  trying "+x);
		if (((needed & x.getMask()) != 0) && x.impliesIgnoreMask(np)) {
		    effective |=  x.getMask();
		    if ((effective & desired) == desired)
			return true;
		    needed = (desired ^ effective);
		}
	    }
	}
	return false;
    }

    /**
     * Adds a permission to the ServicePermissions. The key for
     * the hash is the name.
     *
     * @param permission the Permission object to add.
     *
     * @exception IllegalArgumentException - if the permission is not a
     *                                       ServicePermission
     *
     * @exception SecurityException - if this PermissionCollection object
     *                                has been marked readonly
     */

    public void add(Permission permission) {
	if (! (permission instanceof ServicePermission))
	    throw new IllegalArgumentException("invalid permission: "+
					       permission);
	if (isReadOnly())
	    throw new SecurityException("attempt to add a Permission to a readonly PermissionCollection");

	synchronized (this) {
	    perms.add(0, permission);
	}
    }

    /**
     * Returns an enumeration of all the ServicePermission objects
     * in the container.
     *
     * @return an enumeration of all the ServicePermission objects.
     */

    public Enumeration elements() {
        // Convert Iterator into Enumeration
	synchronized (this) {
	    return Collections.enumeration(perms);
	}
    }

    private static final long serialVersionUID = -4118834211490102011L;

    // Need to maintain serialization interoperability with earlier releases,
    // which had the serializable field:
    // private Vector permissions;

    /**
     * @serialField permissions java.util.Vector
     *     A list of ServicePermission objects.
     */
    private static final ObjectStreamField[] serialPersistentFields = {
        new ObjectStreamField("permissions", Vector.class),
    };

    /**
     * @serialData "permissions" field (a Vector containing the ServicePermissions).
     */
    /*
     * Writes the contents of the perms field out as a Vector for
     * serialization compatibility with earlier releases.
     */
    private void writeObject(ObjectOutputStream out) throws IOException {
	// Don't call out.defaultWriteObject()

	// Write out Vector
	Vector permissions = new Vector(perms.size());

	synchronized (this) {
	    permissions.addAll(perms);
	}

        ObjectOutputStream.PutField pfields = out.putFields();
        pfields.put("permissions", permissions);
        out.writeFields();
    }

    /*
     * Reads in a Vector of ServicePermissions and saves them in the perms field.
     */
    private void readObject(ObjectInputStream in) throws IOException, 
    ClassNotFoundException {
	// Don't call defaultReadObject()

	// Read in serialized fields
	ObjectInputStream.GetField gfields = in.readFields();

	// Get the one we want
	Vector permissions = (Vector)gfields.get("permissions", null);
	perms = new ArrayList(permissions.size());
	perms.addAll(permissions);
    }
}