Returns the set of permissions corresponding to a given String representation.

The perms parameter is a String representing the permissions. It has 9 characters that are interpreted as three sets of three. The first set refers to the owner's permissions; the next to the group permissions and the last to others. Within each set, the first character is 'r' to indicate permission to read, the second character is 'w' to indicate permission to write, and the third character is 'x' for execute permission. Where a permission is not set then the corresponding character is set to '-'.

Usage Example: Suppose we require the set of permissions that indicate the owner has read, write, and execute permissions, the group has read and execute permissions and others have none.

   Set<PosixFilePermission> perms = PosixFilePermissions.fromString("rwxr-x---");

Parameters:

perms string representing a set of permissions

Returns: the resulting set of permissions

Exceptions:

IllegalArgumentException if the string cannot be converted to a set of permissions