java.security
Class PermissionCollection

java.lang.Object
  extended by java.security.PermissionCollection
All Implemented Interfaces:
Serializable
Direct Known Subclasses:
Permissions

public abstract class PermissionCollection
extends Object
implements Serializable

This class models a group of Java permissions. It has convenient methods for determining whether or not a given permission is implied by any of the permissions in this collection.

Some care must be taken in storing permissions. First, a collection of the appropriate type must be created. This is done by calling the newPermissionCollection method on an object of the permission class you wish to add to the collection. If this method returns null, any type of PermissionCollection can be used to store permissions of that type. However, if a PermissionCollection collection object is returned, that type must be used.

A PermissionCollection returned by the newPermissionCollection method in a subclass of Permission is a homogeneous collection. It only will hold permissions of one specified type - instances of the class that created it. Not all PermissionCollection subclasses have to hold permissions of only one type however. For example, the Permissions class holds permissions of many types.

Since the newPermissionCollection in Permission itself returns null, by default a permission can be stored in any type of collection unless it overrides that method to create its own collection type.

Since:
1.1
See Also:
Permission, Permissions, Serialized Form

Constructor Summary
PermissionCollection()
          Create a new collection.
 
Method Summary
abstract  void add(Permission perm)
          This method adds a new Permission object to the collection.
abstract  Enumeration<Permission> elements()
          This method returns an Enumeration of all the objects in this collection.
abstract  boolean implies(Permission perm)
          This method tests whether the specified Permission object is implied by this collection of Permission objects.
 boolean isReadOnly()
          This method tests whether or not this PermissionCollection object is read only.
 void setReadOnly()
          This method sets this PermissionCollection object to be read only.
 String toString()
          This method returns a String representation of this collection.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

PermissionCollection

public PermissionCollection()
Create a new collection.

Method Detail

add

public abstract void add(Permission perm)
This method adds a new Permission object to the collection.

Parameters:
perm - the Permission to add
Throws:
SecurityException - if the collection is marked read only
IllegalArgumentException - if perm is of the wrong type

implies

public abstract boolean implies(Permission perm)
This method tests whether the specified Permission object is implied by this collection of Permission objects.

Parameters:
perm - the Permission object to test
Returns:
true if the collection implies perm

elements

public abstract Enumeration<Permission> elements()
This method returns an Enumeration of all the objects in this collection.

Returns:
an Enumeration of this collection's objects

setReadOnly

public void setReadOnly()
This method sets this PermissionCollection object to be read only. No further permissions can be added to it after calling this method.


isReadOnly

public boolean isReadOnly()
This method tests whether or not this PermissionCollection object is read only.

Returns:
true if this collection is read only

toString

public String toString()
This method returns a String representation of this collection. It is formed by:
 super.toString()" (\n"
   // enumerate all permissions, one per line
 ")\n"
 

Overrides:
toString in class Object
Returns:
a String representing this object
See Also:
Object.getClass(), Object.hashCode(), Class.getName(), Integer.toHexString(int)