Class Permissions

java.lang.Object

java.security.PermissionCollection

java.security.Permissions

All Implemented Interfaces:

Serializable

public final class Permissions
extends PermissionCollection
implements Serializable

This class represents a heterogeneous collection of permissions. That is, it contains different types of Permission objects, organized into PermissionCollection objects. For example, if any java.io.FilePermission objects are added to an instance of this class, they are all stored in a single PermissionCollection. It is the PermissionCollection returned by a call to the newPermissionCollection method in the FilePermission class. Similarly, any java.lang.RuntimePermission objects are stored in the PermissionCollection returned by a call to the newPermissionCollection method in the RuntimePermission class. Thus, this class represents a collection of PermissionCollection objects.

When the add method is called to add a Permission, the Permission is stored in the appropriate PermissionCollection. If no such collection exists yet, the Permission object's class is determined and the newPermissionCollection method is called on that class to create the PermissionCollection and add it to the Permissions object. If newPermissionCollection returns null, then a default PermissionCollection that uses a hashtable will be created and used. Each hashtable entry stores a Permission object as both the key and the value.

Enumerations returned via the elements method are not fail-fast. Modifications to a collection should not be performed while enumerating over that collection.

Since:

1.2

See Also:

• Permission
• PermissionCollection
• AllPermission

Constructor Summary

Constructors

Constructor	Description
Permissions()	Creates a new Permissions object containing no PermissionCollection objects.

Method Summary

Modifier and Type	Method	Description
void	add(Permission permission)	Adds a Permission object to the PermissionCollection for the class the permission belongs to.
Enumeration<Permission>	elements()	Returns an enumeration of all the Permission objects in all the PermissionCollection objects in this Permissions object.
boolean	implies(Permission permission)	Checks to see if this object's PermissionCollection for permissions of the specified permission's class implies the permissions expressed in the permission object.

Methods declared in class PermissionCollection

elementsAsStream, isReadOnly, setReadOnly, toString

Modifier and Type	Method	Description
Stream<Permission>	elementsAsStream()	Returns a stream of all the Permission objects in the collection.
boolean	isReadOnly()	Returns true if this PermissionCollection object is marked as readonly.
void	setReadOnly()	Marks this PermissionCollection object as "readonly".
String	toString()	Returns a string describing this PermissionCollection object, providing information about all the permissions it contains.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Constructor Details

Permissions

public Permissions()

Creates a new Permissions object containing no PermissionCollection objects.

Method Details

add

public void add(Permission permission)

Adds a Permission object to the PermissionCollection for the class the permission belongs to. For example, if permission is a FilePermission, it is added to the FilePermissionCollection stored in this Permissions object. This method creates a new PermissionCollection object (and adds the permission to it) if an appropriate collection does not yet exist.

Specified by:

add in class PermissionCollection

Parameters:

permission - the Permission object to add.

Throws:

SecurityException - if this Permissions object is marked as readonly.

See Also:

• PermissionCollection.isReadOnly()

implies

public boolean implies(Permission permission)

Checks to see if this object's PermissionCollection for permissions of the specified permission's class implies the permissions expressed in the permission object. Returns true if the combination of permissions in the appropriate PermissionCollection (e.g., a FilePermissionCollection for a FilePermission) together imply the specified permission.

For example, suppose there is a FilePermissionCollection in this Permissions object, and it contains one FilePermission that specifies "read" access for all files in all subdirectories of the "/tmp" directory, and another FilePermission that specifies "write" access for all files in the "/tmp/scratch/foo" directory. Then if the implies method is called with a permission specifying both "read" and "write" access to files in the "/tmp/scratch/foo" directory, true is returned.

Additionally, if this PermissionCollection contains the AllPermission, this method will always return true.

Specified by:

implies in class PermissionCollection

Parameters:

permission - the Permission object to check.

Returns:

true if "permission" is implied by the permissions in the PermissionCollection it belongs to, false if not.

elements

public Enumeration<Permission> elements()

Returns an enumeration of all the Permission objects in all the PermissionCollection objects in this Permissions object.

Specified by:

elements in class PermissionCollection

Returns:

an enumeration of all the Permission objects.

See Also:

• PermissionCollection.elementsAsStream()