java.util
Class PropertyPermission

java.lang.Object
  extended byjava.security.Permission
      extended byjava.security.BasicPermission
          extended byjava.util.PropertyPermission
All Implemented Interfaces:
java.security.Guard, Serializable

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).

Since:
1.2
Author:
Roland Schemers
See Also:
BasicPermission, Permission, Permissions, PermissionCollection, SecurityManager

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
 
Fields inherited from class java.security.Permission
 
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
 
Methods inherited from class java.security.Permission
checkGuard, getName, toString
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

READ

private static final int READ
Read action.

See Also:
Constant Field Values

WRITE

private static final int WRITE
Write action.

See Also:
Constant Field Values

ALL

private static final int ALL
All actions (read,write);

See Also:
Constant Field Values

NONE

private static final int NONE
No actions.

See Also:
Constant Field Values

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:

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

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.

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.

getMask

private static int getMask(String actions)
Converts an actions String to an actions mask.

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.

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.

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.

Throws:
IOException

readObject

private void readObject(ObjectInputStream s)
                 throws IOException,
                        ClassNotFoundException
readObject is called to restore the state of the PropertyPermission from a stream.

Throws:
IOException
ClassNotFoundException