java.util
Class PropertyPermission

java.lang.Object
  |
  +--java.security.Permission
        |
        +--java.security.BasicPermission
              |
              +--java.util.PropertyPermission

public final class PropertyPermission

extends java.security.BasicPermission

This class is for property permissions.

The name is the name of the property ("java.home", "os.name", etc). The naming convention follows the hierarchical property naming convention. Also, an asterisk may appear at the end of the name, following a ".", or by itself, to signify a wildcard match. For example: "java.*" or "*" is valid, "*java" or "a*b" is not valid.

The actions to be granted are passed to the constructor in a string containing a list of zero or more comma-separated keywords. The possible keywords are "read" and "write". Their meaning is defined as follows:

read

read permission. Allows System.getProperty to be called.

write

write permission. Allows System.setProperty to be called.

The actions string is converted to lowercase before processing.

Care should be taken before granting code permission to access certain system properties. For example, granting permission to access the "java.home" system property gives potentially malevolent code sensitive information about the system environment (the Java installation directory). Also, granting permission to access the "user.name" and "user.home" system properties gives potentially malevolent code sensitive information about the user environment (the user's account name and home directory).

See Also:

BasicPermission, Permission, java.security.Permissions, PermissionCollection, SecurityManager, Serialized Form

Field Summary

private String	actions The actions string.
private static int	ALL All actions (read,write);
private int	mask The actions mask.
private static int	NONE No actions.
private static int	READ Read action.
private static int	WRITE Write action.

Fields inherited from class java.security.BasicPermission

path, wildcard

Fields inherited from class java.security.Permission

name

Constructor Summary

PropertyPermission(String name, String actions)
Creates a new PropertyPermission object with the specified name.

Method Summary

boolean	equals(Object obj) Checks two PropertyPermission objects for equality.
String	getActions() Returns the "canonical string representation" of the actions.
(package private) static String	getActions(int mask) Return the canonical string representation of the actions.
(package private) int	getMask() Return the current action mask.
private static int	getMask(String actions) Converts an actions String to an actions mask.
int	hashCode() Returns the hash code value for this object.
boolean	implies(java.security.Permission p) Checks if this PropertyPermission object "implies" the specified permission.
private void	init(int mask) initialize a PropertyPermission object.
java.security.PermissionCollection	newPermissionCollection() Returns a new PermissionCollection object for storing PropertyPermission objects.
private void	readObject(ObjectInputStream s) readObject is called to restore the state of the PropertyPermission from a stream.
private void	writeObject(ObjectOutputStream s) WriteObject is called to save the state of the PropertyPermission to a stream.

Methods inherited from class java.security.BasicPermission

init

Methods inherited from class java.security.Permission

checkGuard, getName, toString

Methods inherited from class java.lang.Object

, clone, finalize, getClass, notify, notifyAll, registerNatives, wait, wait, wait

Field Detail

READ

private static final int READ

Read action.

WRITE

private static final int WRITE

Write action.

ALL

private static final int ALL

All actions (read,write);

NONE

private static final int NONE

No actions.

mask

private transient int mask

The actions mask.

actions

private String actions

The actions string.

Constructor Detail

PropertyPermission

public PropertyPermission(String name,
                          String actions)

Creates a new PropertyPermission object with the specified name. The name is the name of the system property, and actions contains a comma-separated list of the desired actions granted on the property. Possible actions are "read" and "write".

Parameters:

name - the name of the PropertyPermission.

actions - the actions string.

Method Detail

init

private void init(int mask)

initialize a PropertyPermission object. Common to all constructors. Also called during de-serialization.

Parameters:

mask - the actions mask to use.

implies

public boolean implies(java.security.Permission p)

Checks if this PropertyPermission object "implies" the specified permission.

More specifically, this method returns true if:

• p is an instanceof PropertyPermission,

• p's actions are a proper subset of this object's actions, and

• p's name is implied by this object's name. For example, "java.*" implies "java.home".

Parameters:

p - the permission to check against.

Returns:

true if the specified permission is implied by this object, false if not.

Overrides:

implies in class java.security.BasicPermission

equals

public boolean equals(Object obj)

Checks two PropertyPermission objects for equality. Checks that obj is a PropertyPermission, and has the same name and actions as this object.

Parameters:

obj - the object we are testing for equality with this object.

Returns:

true if obj is a PropertyPermission, and has the same name and actions as this PropertyPermission object.

Overrides:

equals in class java.security.BasicPermission

hashCode

public int hashCode()

Returns the hash code value for this object. The hash code used is the hash code of this permissions name, that is, getName().hashCode(), where getName is from the Permission superclass.

Returns:

a hash code value for this object.

Overrides:

hashCode in class java.security.BasicPermission

getMask

private static int getMask(String actions)

Converts an actions String to an actions mask.

Parameters:

action - the action string.

Returns:

the actions mask.

getActions

static String getActions(int mask)

Return the canonical string representation of the actions. Always returns present actions in the following order: read, write.

Returns:

the canonical string representation of the actions.

getActions

public String getActions()

Returns the "canonical string representation" of the actions. That is, this method always returns present actions in the following order: read, write. For example, if this PropertyPermission object allows both write and read actions, a call to getActions will return the string "read,write".

Returns:

the canonical string representation of the actions.

Overrides:

getActions in class java.security.BasicPermission

getMask

int getMask()

Return the current action mask. Used by the PropertyPermissionCollection

Returns:

the actions mask.

newPermissionCollection

public java.security.PermissionCollection newPermissionCollection()

Returns a new PermissionCollection object for storing PropertyPermission objects.

Returns:

a new PermissionCollection object suitable for storing PropertyPermissions.

Overrides:

newPermissionCollection in class java.security.BasicPermission

writeObject

private void writeObject(ObjectOutputStream s)
                  throws IOException

WriteObject is called to save the state of the PropertyPermission to a stream. The actions are serialized, and the superclass takes care of the name.

readObject

private void readObject(ObjectInputStream s)
                 throws IOException,
                        ClassNotFoundException

readObject is called to restore the state of the PropertyPermission from a stream.

Overrides:

readObject in class java.security.BasicPermission