java.io
Class FilePermission

java.lang.Object sample code for java.lang.Object definition code for java.lang.Object 
  extended by java.security.Permission sample code for java.security.Permission definition code for java.security.Permission 
      extended by java.io.FilePermission
All Implemented Interfaces:
Serializable sample code for java.io.Serializable definition code for java.io.Serializable , Guard sample code for java.security.Guard definition code for java.security.Guard

public final class FilePermission
extends Permission sample code for java.security.Permission definition code for java.security.Permission
implements Serializable sample code for java.io.Serializable definition code for java.io.Serializable

This class represents access to a file or directory. A FilePermission consists of a pathname and a set of actions valid for that pathname.

Pathname is the pathname of the file or directory granted the specified actions. A pathname that ends in "/*" (where "/" is the file separator character, File.separatorChar) indicates all the files and directories contained in that directory. A pathname that ends with "/-" indicates (recursively) all files and subdirectories contained in that directory. A pathname consisting of the special token "<<ALL FILES>>" matches any file.

Note: A pathname consisting of a single "*" indicates all the files in the current directory, while a pathname consisting of a single "-" indicates all the files in the current directory and (recursively) all files and subdirectories contained in the current directory.

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

read
read permission
write
write permission
execute
execute permission. Allows Runtime.exec to be called. Corresponds to SecurityManager.checkExec.
delete
delete permission. Allows File.delete to be called. Corresponds to SecurityManager.checkDelete.

The actions string is converted to lowercase before processing.

Be careful when granting FilePermissions. Think about the implications of granting read and especially write access to various files and directories. The "<<ALL FILES>>" permission with write action is especially dangerous. This grants permission to write to the entire file system. One thing this effectively allows is replacement of the system binary, including the JVM runtime environment.

Please note: Code can always read a file from the same directory it's in (or a subdirectory of that directory); it does not need explicit permission to do so.

Since:
1.2
See Also:
Permission sample code for java.security.Permission definition code for java.security.Permission , Permissions sample code for java.security.Permissions definition code for java.security.Permissions , PermissionCollection sample code for java.security.PermissionCollection definition code for java.security.PermissionCollection

Constructor Summary
FilePermission sample code for java.io.FilePermission.FilePermission(java.lang.String, java.lang.String) definition code for java.io.FilePermission.FilePermission(java.lang.String, java.lang.String) (String sample code for java.lang.String definition code for java.lang.String  path, String sample code for java.lang.String definition code for java.lang.String  actions)
          Creates a new FilePermission object with the specified actions.
 
Method Summary
 boolean equals sample code for java.io.FilePermission.equals(java.lang.Object) definition code for java.io.FilePermission.equals(java.lang.Object) (Object sample code for java.lang.Object definition code for java.lang.Object  obj)
          Checks two FilePermission objects for equality.
 String sample code for java.lang.String definition code for java.lang.String getActions sample code for java.io.FilePermission.getActions() definition code for java.io.FilePermission.getActions() ()
          Returns the "canonical string representation" of the actions.
 int hashCode sample code for java.io.FilePermission.hashCode() definition code for java.io.FilePermission.hashCode() ()
          Returns the hash code value for this object.
 boolean implies sample code for java.io.FilePermission.implies(java.security.Permission) definition code for java.io.FilePermission.implies(java.security.Permission) (Permission sample code for java.security.Permission definition code for java.security.Permission  p)
          Checks if this FilePermission object "implies" the specified permission.
 PermissionCollection sample code for java.security.PermissionCollection definition code for java.security.PermissionCollection newPermissionCollection sample code for java.io.FilePermission.newPermissionCollection() definition code for java.io.FilePermission.newPermissionCollection() ()
          Returns a new PermissionCollection object for storing FilePermission objects.
 
Methods inherited from class java.security.Permission sample code for java.security.Permission definition code for java.security.Permission
checkGuard sample code for java.security.Permission.checkGuard(java.lang.Object) definition code for java.security.Permission.checkGuard(java.lang.Object) , getName sample code for java.security.Permission.getName() definition code for java.security.Permission.getName() , toString sample code for java.security.Permission.toString() definition code for java.security.Permission.toString()
 
Methods inherited from class java.lang.Object sample code for java.lang.Object definition code for java.lang.Object
clone sample code for java.lang.Object.clone() definition code for java.lang.Object.clone() , finalize sample code for java.lang.Object.finalize() definition code for java.lang.Object.finalize() , getClass sample code for java.lang.Object.getClass() definition code for java.lang.Object.getClass() , notify sample code for java.lang.Object.notify() definition code for java.lang.Object.notify() , notifyAll sample code for java.lang.Object.notifyAll() definition code for java.lang.Object.notifyAll() , wait sample code for java.lang.Object.wait() definition code for java.lang.Object.wait() , wait sample code for java.lang.Object.wait(long) definition code for java.lang.Object.wait(long) , wait sample code for java.lang.Object.wait(long, int) definition code for java.lang.Object.wait(long, int)
 

Constructor Detail

FilePermission sample code for java.io.FilePermission(java.lang.String, java.lang.String) definition code for java.io.FilePermission(java.lang.String, java.lang.String)

public FilePermission(String sample code for java.lang.String definition code for java.lang.String  path,
                      String sample code for java.lang.String definition code for java.lang.String  actions)
Creates a new FilePermission object with the specified actions. path is the pathname of a file or directory, and actions contains a comma-separated list of the desired actions granted on the file or directory. Possible actions are "read", "write", "execute", and "delete".

A pathname that ends in "/*" (where "/" is the file separator character, File.separatorChar) indicates a directory and all the files contained in that directory. A pathname that ends with "/-" indicates a directory and (recursively) all files and subdirectories contained in that directory. The special pathname "<<ALL FILES>>" matches all files.

A pathname consisting of a single "*" indicates all the files in the current directory, while a pathname consisting of a single "-" indicates all the files in the current directory and (recursively) all files and subdirectories contained in the current directory.

Parameters:
path - the pathname of the file/directory.
actions - the action string.
Method Detail

implies sample code for java.io.FilePermission.implies(java.security.Permission) definition code for java.io.FilePermission.implies(java.security.Permission)

public boolean implies(Permission sample code for java.security.Permission definition code for java.security.Permission  p)
Checks if this FilePermission object "implies" the specified permission.

More specifically, this method returns true if:

Specified by:
implies sample code for java.security.Permission.implies(java.security.Permission) definition code for java.security.Permission.implies(java.security.Permission) in class Permission sample code for java.security.Permission definition code for java.security.Permission
Parameters:
p - the permission to check against.
Returns:
true if the specified permission is implied by this object, false if not.

equals sample code for java.io.FilePermission.equals(java.lang.Object) definition code for java.io.FilePermission.equals(java.lang.Object)

public boolean equals(Object sample code for java.lang.Object definition code for java.lang.Object  obj)
Checks two FilePermission objects for equality. Checks that obj is a FilePermission, and has the same pathname and actions as this object.

Specified by:
equals sample code for java.security.Permission.equals(java.lang.Object) definition code for java.security.Permission.equals(java.lang.Object) in class Permission sample code for java.security.Permission definition code for java.security.Permission
Parameters:
obj - the object we are testing for equality with this object.
Returns:
true if obj is a FilePermission, and has the same pathname and actions as this FilePermission object.
See Also:
Object.hashCode() sample code for java.lang.Object.hashCode() definition code for java.lang.Object.hashCode() , Hashtable sample code for java.util.Hashtable definition code for java.util.Hashtable

hashCode sample code for java.io.FilePermission.hashCode() definition code for java.io.FilePermission.hashCode()

public int hashCode()
Returns the hash code value for this object.

Specified by:
hashCode sample code for java.security.Permission.hashCode() definition code for java.security.Permission.hashCode() in class Permission sample code for java.security.Permission definition code for java.security.Permission
Returns:
a hash code value for this object.
See Also:
Object.equals(java.lang.Object) sample code for java.lang.Object.equals(java.lang.Object) definition code for java.lang.Object.equals(java.lang.Object) , Hashtable sample code for java.util.Hashtable definition code for java.util.Hashtable

getActions sample code for java.io.FilePermission.getActions() definition code for java.io.FilePermission.getActions()

public String sample code for java.lang.String definition code for java.lang.String  getActions()
Returns the "canonical string representation" of the actions. That is, this method always returns present actions in the following order: read, write, execute, delete. For example, if this FilePermission object allows both write and read actions, a call to getActions will return the string "read,write".

Specified by:
getActions sample code for java.security.Permission.getActions() definition code for java.security.Permission.getActions() in class Permission sample code for java.security.Permission definition code for java.security.Permission
Returns:
the canonical string representation of the actions.

newPermissionCollection sample code for java.io.FilePermission.newPermissionCollection() definition code for java.io.FilePermission.newPermissionCollection()

public PermissionCollection sample code for java.security.PermissionCollection definition code for java.security.PermissionCollection  newPermissionCollection()
Returns a new PermissionCollection object for storing FilePermission objects.

FilePermission objects must be stored in a manner that allows them to be inserted into the collection in any order, but that also enables the PermissionCollection implies method to be implemented in an efficient (and consistent) manner.

For example, if you have two FilePermissions:

  1. "/tmp/-", "read"
  2. "/tmp/scratch/foo", "write"

and you are calling the implies method with the FilePermission:

   "/tmp/scratch/foo", "read,write", 
 
then the implies function must take into account both the "/tmp/-" and "/tmp/scratch/foo" permissions, so the effective permission is "read,write", and implies returns true. The "implies" semantics for FilePermissions are handled properly by the PermissionCollection object returned by this newPermissionCollection method.

Overrides:
newPermissionCollection sample code for java.security.Permission.newPermissionCollection() definition code for java.security.Permission.newPermissionCollection() in class Permission sample code for java.security.Permission definition code for java.security.Permission
Returns:
a new PermissionCollection object suitable for storing FilePermissions.