Package com.squareup.okhttp.internal.io

Interface FileSystem

public interface FileSystem

Access to read and write files on a hierarchical data store. Most callers should use the SYSTEM implementation, which uses the host machine's local file system. Alternate implementations may be used to inject faults (for testing) or to transform stored data (to add encryption, for example).

All operations on a file system are racy. For example, guarding a call to source(java.io.File) with exists(java.io.File) does not guarantee that FileNotFoundException will not be thrown. The file may be moved between the two calls!

This interface is less ambitious than FileSystem introduced in Java 7. It lacks important features like file watching, metadata, permissions, and disk space information. In exchange for these limitations, this interface is easier to implement and works on all versions of Java and Android.

Field Summary

Fields

Modifier and Type	Field	Description
static FileSystem	SYSTEM	The host machine's local file system.

Method Summary

Modifier and Type	Method	Description
Sink	appendingSink(File file)	Writes to file, appending if data is already present.
void	delete(File file)	Deletes file if it exists.
void	deleteContents(File directory)	Recursively delete the contents of directory.
boolean	exists(File file)	Returns true if file exists on the file system.
void	rename(File from, File to)	Renames from to to.
Sink	sink(File file)	Writes to file, discarding any data already present.
long	size(File file)	Returns the number of bytes stored in file, or 0 if it does not exist.
Source	source(File file)	Reads from file.

Field Detail

SYSTEM

static final FileSystem SYSTEM

The host machine's local file system.

Method Detail

source

Source source(File file)
       throws FileNotFoundException

Reads from file.

Throws:

FileNotFoundException

sink

Sink sink(File file)
   throws FileNotFoundException

Writes to file, discarding any data already present. Creates parent directories if necessary.

Throws:

FileNotFoundException

appendingSink

Sink appendingSink(File file)
            throws FileNotFoundException

Writes to file, appending if data is already present. Creates parent directories if necessary.

Throws:

FileNotFoundException

delete

void delete(File file)
     throws IOException

Deletes file if it exists. Throws if the file exists and cannot be deleted.

Throws:

IOException

exists

boolean exists(File file)
        throws IOException

Returns true if file exists on the file system.

Throws:

IOException

size

long size(File file)

Returns the number of bytes stored in file, or 0 if it does not exist.

rename

void rename(File from,
            File to)
     throws IOException

Renames from to to. Throws if the file cannot be renamed.

Throws:

IOException

deleteContents

void deleteContents(File directory)
             throws IOException

Recursively delete the contents of directory. Throws an IOException if any file could not be deleted, or if dir is not a readable directory.

Throws:

IOException