java.security
Class Permission

java.lang.Object
  |
  +--java.security.Permission
All Implemented Interfaces:
Guard, Serializable
Direct Known Subclasses:
AllPermission, BasicPermission, FilePermission, SocketPermission, UnresolvedPermission

public abstract class Permission
extends Object
implements Guard, Serializable

Untamed:

See Also:
Serialized Form

Field Summary
private  String name
           
 
Constructor Summary
Permission(String name)
          Enabled: Constructs a permission with the specified name.
 
Method Summary
 void checkGuard(Object object)
          Enabled: Implements the guard interface for a permission.
abstract  boolean equals(Object obj)
          Suppressed: Checks two Permission objects for equality.
abstract  String getActions()
          Enabled: Returns the actions as a String.
 String getName()
          Enabled: Returns the name of this Permission.
abstract  int hashCode()
          Suppressed: Returns the hash code value for this Permission object.
abstract  boolean implies(Permission permission)
          Enabled: Checks if the specified permission's actions are "implied by" this object's actions.
 PermissionCollection newPermissionCollection()
          Enabled: Returns an empty PermissionCollection for a given Permission object, or null if one is not defined.
 String toString()
          Suppressed: Returns a string describing this Permission.
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

name

private String name
Constructor Detail

Permission

public Permission(String name)
Enabled: Constructs a permission with the specified name.

Parameters:
name - name of the Permission object being created.
Method Detail

checkGuard

public void checkGuard(Object object)
                throws SecurityException
Enabled: Implements the guard interface for a permission. The SecurityManager.checkPermission method is called, passing this permission object as the permission to check. Returns silently if access is granted. Otherwise, throws a SecurityException.

Specified by:
checkGuard in interface Guard
Parameters:
object - the object being guarded (currently ignored).
Throws:
SecurityException - if a security manager exists and its checkPermission method doesn't allow access.
See Also:
Guard, GuardedObject, SecurityManager.checkPermission(java.security.Permission)

implies

public abstract boolean implies(Permission permission)
Enabled: Checks if the specified permission's actions are "implied by" this object's actions.

This must be implemented by subclasses of Permission, as they are the only ones that can impose semantics on a Permission object.

The implies method is used by the AccessController to determine whether or not a requested permission is implied by another permission that is known to be valid in the current execution context.

Parameters:
permission - the permission to check against.
Returns:
true if the specified permission is implied by this object, false if not.

equals

public abstract boolean equals(Object obj)
Suppressed: Checks two Permission objects for equality.

Do not use the equals method for making access control decisions; use the implies method.

Overrides:
equals in class Object
Parameters:
obj - the object we are testing for equality with this object.
Returns:
true if both Permission objects are equivalent.
See Also:
Object.hashCode(), java.util.Hashtable

hashCode

public abstract int hashCode()
Suppressed: Returns the hash code value for this Permission object.

The required hashCode behavior for Permission Objects is the following:

Overrides:
hashCode in class Object
Returns:
a hash code value for this object.
See Also:
java.lang.Object#equals(java.lang.Object), java.util.Hashtable

getName

public final String getName()
Enabled: Returns the name of this Permission. For example, in the case of a java.io.FilePermission, the name will be a pathname.

Returns:
the name of this Permission.

getActions

public abstract String getActions()
Enabled: Returns the actions as a String. This is abstract so subclasses can defer creating a String representation until one is needed. Subclasses should always return actions in what they consider to be their canonical form. For example, two FilePermission objects created via the following:
   perm1 = new FilePermission(p1,"read,write");
   perm2 = new FilePermission(p2,"write,read"); 
 
both return "read,write" when the getActions method is invoked.

Returns:
the actions of this Permission.

newPermissionCollection

public PermissionCollection newPermissionCollection()
Enabled: Returns an empty PermissionCollection for a given Permission object, or null if one is not defined. Subclasses of class Permission should override this if they need to store their permissions in a particular PermissionCollection object in order to provide the correct semantics when the PermissionCollection.implies method is called. If null is returned, then the caller of this method is free to store permissions of this type in any PermissionCollection they choose (one that uses a Hashtable, one that uses a Vector, etc).

Returns:
a new PermissionCollection object for this type of Permission, or null if one is not defined.

toString

public String toString()
Suppressed: Returns a string describing this Permission. The convention is to specify the class name, the permission name, and the actions in the following format: '("ClassName" "name" "actions")'.

Overrides:
toString in class Object
Returns:
information about this Permission.


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