Class HierarchicalFileSystem

java.lang.Object
  HierarchicalFileSystem

public class HierarchicalFileSystem

extends java.lang.Object

A HierarchicalFileSystem represents a hierarchical file system in which files are referenced by UNIX style path names.

Field Summary

private BaseFileSystem	base base is the base file system wrapped by this hierarchical file system.
private int	root root is the file number of the root directory of this hierarchical file system.

Constructor Summary

HierarchicalFileSystem(BaseFileSystem bfs)
new HierarchicalFileSystem(bfs) returns a new hierarchical file system wrapper for the base file system bfs.

Method Summary

private void	checkTestPath(java.lang.String pth) checkTestPath(pth) prints pth and its tail and last directory.
void	create(java.lang.String pth) fs.create(pth) creates a regular file with absolute path pth in fs.
void	createDir(java.lang.String pth) fs.createDir(pth) creates a new directory with absolute path pth in fs.
void	delete(java.lang.String pth) fs.delete(pth) removes the regular file with absolute path pth from fs.
void	deleteDir(java.lang.String pth) fs.deleteDir(pth) removes the directory with absolute path pth from fs.
int	getCapacity() fs.getCapacity() returns the maximum number of files for fs.
private Directory	getLastDir(java.lang.String pth) getLastDir(pth) returns the directory before the tail of pth or null if there is no such directory.
private java.lang.String	getTail(java.lang.String pth) getTail(pth) returns the name at the tail of pth.
private void	initForTest() initForTest() manually creates directories and files for testing purposes.
static void	main(java.lang.String[] args) main(args) is a program for testing the private methods of the HierarchicalFileSystem class.
File	open(java.lang.String pth) fs.open(pth) returns a file access structure for the file with absolute path pth.
File	openDir(java.lang.String pth) fs.openDir(pth) returns a directory access structure for the directory with absolute path pth.
java.lang.String	toString() fs.toString() returns the class name and file system name of fs as a string.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

base

private BaseFileSystem base

base is the base file system wrapped by this hierarchical file system.

root

private int root

root is the file number of the root directory of this hierarchical file system.

Constructor Detail

HierarchicalFileSystem

public HierarchicalFileSystem(BaseFileSystem bfs)

new HierarchicalFileSystem(bfs) returns a new hierarchical file system wrapper for the base file system bfs.

Method Detail

getTail

private java.lang.String getTail(java.lang.String pth)

getTail(pth) returns the name at the tail of pth. If pth ends with '/' then getTail returns an empty string.

getLastDir

private Directory getLastDir(java.lang.String pth)

getLastDir(pth) returns the directory before the tail of pth or null if there is no such directory. The last directory before the tail of "/" is the root directory.

initForTest

private void initForTest()

initForTest() manually creates directories and files for testing purposes. This method is only invoked from the main() method.

checkTestPath

private void checkTestPath(java.lang.String pth)

checkTestPath(pth) prints pth and its tail and last directory. This method is only invoked from the main() method.

create

public void create(java.lang.String pth)

fs.create(pth) creates a regular file with absolute path pth in fs.

An IllegalStateException is thrown

• if there is no space in fs for a new file.

An IllegalArgumentException is thrown

• if any of the directories in pth is missing.

createDir

public void createDir(java.lang.String pth)

fs.createDir(pth) creates a new directory with absolute path pth in fs.

An IllegalStateException is thrown

• if there is no space in fs for a new file.

An IllegalArgumentException is thrown if any of the directories in pth except the last is missing.

delete

public void delete(java.lang.String pth)

fs.delete(pth) removes the regular file with absolute path pth from fs.

An IllegalArgumentException is thrown

• if there is no such file, or
• if pth refers to a directory.

deleteDir

public void deleteDir(java.lang.String pth)

fs.deleteDir(pth) removes the directory with absolute path pth from fs.

An IllegalArgumentException is thrown

• if pth is "/", or
• if there is no such directory, or
• if pth refers to a regular file, or
• if pth refers to a non-empty directory.

open

public File open(java.lang.String pth)

fs.open(pth) returns a file access structure for the file with absolute path pth.

Null is returned

• if there is no such file, or
• if pth refers to a directory.

openDir

public File openDir(java.lang.String pth)

fs.openDir(pth) returns a directory access structure for the directory with absolute path pth.

Null is returned

• if there is no such directory, or
• if pth refers to a regular file.

getCapacity

public int getCapacity()

fs.getCapacity() returns the maximum number of files for fs.

toString

public java.lang.String toString()

fs.toString() returns the class name and file system name of fs as a string.

main

public static void main(java.lang.String[] args)

main(args) is a program for testing the private methods of the HierarchicalFileSystem class.