Java Reference
In-Depth Information
The root is D:\
TryPath.java is a file containing 2121 bytes.
D:\Beginning Java SE 7\Projects\TryPath\src\TryPath.java was created
2011-03-23T18:33:22.315038Z
D:\Beginning Java SE 7\Projects\TryPath\src\TryPath.java was last
accessed
2011-05-08T10:48:55.974509Z
D:\Beginning Java SE 7\Projects\TryPath\src\TryPath.java was last
modified
2011-05-08T10:48:55.976509Z
D:\Beginning Java SE 7\Projects\TryPath\src\TryPath.java is 2121
bytes.
How It Works
The analysis of a path is carried out in the static
checkPath()
method so I'm explaining that first. The
first statement in this method calls the
getNameCount()
for the
Path
object that is passed as the argu-
ment to obtain the number of elements in the path. The
if
statement that follows calls
isAbsolute()
for
the
Path
object to determine if the object contains an absolute or a relative path. Up to this point there
has been no interaction with the file system. All operations just involve the
Path
object.
If the path is not absolute, the
toAbsolutePath()
method for the
Path
object is called to convert it. This
does access the file system and has the potential to throw a
SecurityException
if you are not permitted
to access the file.
Next the static
notExists()
method in the
Files
class is called to see whether
path
references
something real. This obviously involves accessing the file system. If the
path
does not reference a file or
directory that exists, the
checkPath()
method returns after outputting the fact.
Having established that
path
refers to a real file or directory, the static
readAttributes()
method in the
Files
class is called with
path
as the first argument to obtain the attributes for whatever
Path
references.
The method then calls the
isDirectory()
method for the
BasicFileAttributes
object to determine if
path
references a directory. The second argument determines that the basic file attributes are retrieved.
You use the
BasicFileAttributes
object to decide whether
path
references a file or a directory and to
obtain various properties of the file or directory.
The
main()
method calls
checkPath()
for three different paths, with the results that you see. You should
supply your own path specifications in this example to suit your particular environment.
Other Path Operations
The
resolve()
method for a
Path
object reference resolves the current path, which should be a directory,
against the
Path
object that is supplied as the argument and returns the resultant
Path
object. Typically the
current path is an absolute path and the argument is a relative path, and the result is the path that is produced
by joining the argument path to the current path. For example, if the current path is
C:\Temp
and the argu-
ment path is
output.txt
, the result is the path
C:\Temp\output.txt
. If the argument is an absolute path,
the argument path is returned, and if the argument is
null
, the current
Path
object is returned. You use this
method later in this chapter when you get to copy files.
