Java Reference
In-Depth Information
Double
This is a wrapper class for double . See Section 5.1 in Chapter 5 .
File
Package: java.io
Ancestor classes:
Object
|
+--File
Many of these methods throw a SecurityException if a security manager exists and is
unhappy with the method invocation. This is not likely to be a concern for readers of this topic,
and we have not noted this in the method descriptions.
The class SecurityException is an unchecked exception class, which means you need not
catch it or declare it in a throws clause.
public File(String fileName)
Constructor. fileName can be either a full or a relative pathname (which includes the case of a
simple fi le name). fileName is referred to as the abstract pathname .
Throws:
NullPointerException if the pathname fileName is null .
public boolean canRead()
Tests whether the program can read from the fi le. Returns true if the fi le named by the abstract
pathname exists and is readable by the program; otherwise returns false .
public boolean canWrite()
Tests whether the program can write to the fi le. Returns true if the fi le named by the abstract
pathname exists and is writable by the program; otherwise returns false .
public boolean createNewFile()
Creates a new empty fi le named by the abstract pathname, provided that a fi le of that name
does not already exist. Returns true if successful; returns false otherwise.
Throws:
IOException if an I/O error occurs.
public boolean delete( )
Tries to delete the fi le or directory named by the abstract pathname. A directory must be empty
to be removed. Returns true if it was able to delete the fi le or directory. Returns false if it was
unable to delete the fi le or directory.
public boolean exists()
Tests whether there is a fi le with the abstract pathname.
 
Search WWH ::




Custom Search