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Class java.io.FilePermission

java.lang.Object
    |
    +----java.security.Permission
            |
            +----java.io.FilePermission

public final class FilePermission

extends Permission

implements Serializable

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 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. A pathname consisting of a single "-" matches any file.

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", "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.

See Also:

Permission, Permissions, PermissionCollection

FilePermission(String, String)

Creates a new FilePermission object with the specified actions.

equals(Object)

Checks two FilePermission objects for equality.

getActions()

Returns the "canonical string representation" of the actions.

hashCode()

Returns the hash code value for this object.

implies(Permission)

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

newPermissionCollection()

Returns a new PermissionCollection object for storing FilePermission objects.

public FilePermission(String path,
                      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.

Parameters:

path - the pathname of the file/directory.

actions - the action string.

public boolean implies(Permission p)

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

More specifically, this method returns true if:

• p is an instanceof FilePermission,

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

• p's pathname is implied by this object's pathname. For example, "/tmp/*" implies "/tmp/foo", since "/tmp/*" encompasses the "/tmp" directory and all files in that directory, including the one named "foo".

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 Permission

public boolean equals(Object obj)

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

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.

Overrides:

equals in class Permission

public int hashCode()

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

Returns:

a hash code value for this object.

Overrides:

hashCode in class Permission

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, execute, delete. For example, if this FilePermission 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 Permission

public 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.

Returns:

a new PermissionCollection object suitable for storing FilePermissions.

Overrides:

newPermissionCollection in class Permission

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