com.caucho.vfs
Class CachePath

java.lang.Object
  |
  +--com.caucho.vfs.Path
        |
        +--com.caucho.vfs.FilesystemPath
              |
              +--com.caucho.vfs.CachePath

public class CachePath

extends FilesystemPath

A cache wrapper over a path. All files are automatically cached. Once the cache is created, you use the file just like any other Path:

 Path root = new CachePath(Vfs.lookup("test/cacheable"));

 ReadStream is = root.lookup("test.file").openRead();
 ...
 is.close();
 

The cache size is governed by two limits: memory size and number of entries. The size of the disk is considered infinite, and it limited only by the number of entries.

The cache entries are stored in an LRU with a capacity of the number of entries. If loading a new file pushes the memory size over the limit, the old files are dropped from the memory cache.

Fields inherited from class com.caucho.vfs.FilesystemPath

bindRoot, pathname, root, separatorChar, userPath

Fields inherited from class com.caucho.vfs.Path

L, schemeMap

Constructor Summary

protected	CachePath(FilesystemPath root, java.lang.String userPath, java.lang.String path) Internal creation of a path for the vfs.
	CachePath(Path root, int entries, long capacity) Creates a new cache.

Method Summary

boolean	canRead() Tests if the file can be read.
boolean	canWrite() Tests if the file can be written.
void	clear() Clear the memory cache.
boolean	equals(java.lang.Object b)
boolean	exists() Returns true if the underlying file exists.
protected Path	fsWalk(java.lang.String userPath, java.util.Map attributes, java.lang.String path) Looks up the cache entry for a given path.
long	getLastModified() Returns the last modified time of the file.
long	getLength() Returns the length of the file in bytes.
java.lang.String	getScheme() The scheme for the path is cache:
int	hashCode() Returns the hash code, which is based on the underlying file.
boolean	isDirectory() Tests if the path refers to a directory.
boolean	isFile() Tests if the path refers to a file.
java.lang.String[]	list()
boolean	mkdir() Creates the directory named by this path.
boolean	mkdirs() Creates the directory named by this path and any parent directories.
StreamImpl	openAppendImpl()
StreamImpl	openReadImpl() Opens a read stream to the path.
StreamImpl	openReadWriteImpl()
StreamImpl	openWriteImpl()
boolean	remove() Removes the file or directory named by this path.
boolean	renameTo(Path path) Renames the file or directory to the name given by the path.
void	setLastModified(long time)
void	setRemoveOnRelease(boolean remove) If set, files bumped from the cache are removed from the underlying filesystem.
void	writeToStream(java.io.OutputStream os) Write the contents of the cache item to the output stream.

Methods inherited from class com.caucho.vfs.FilesystemPath

bind, copy, createRoot, getFullPath, getParent, getPath, getTail, getURL, getUserPath, normalizePath, normalizePath, schemeWalk, setUserPath, toString

Methods inherited from class com.caucho.vfs.Path

createNewFile, createRoot, createTempFile, getAttribute, getAttributeNames, getContentType, getHost, getNativePath, getObject, getPort, getQuery, getResources, getResources, getValue, isObject, iterator, lookup, lookup, lookupNative, lookupNative, openAppend, openRead, openReadWrite, openReadWrite, openWrite, removeAttribute, renameTo, scanScheme, setAttribute, setObject, setValue, unbind

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

CachePath

public CachePath(Path root,
                 int entries,
                 long capacity)

Creates a new cache.

Parameters:

root - underlying backing store.

entries - the number of entries in the cache.

capacity - total size in bytes allowed in the memory cache.

CachePath

protected CachePath(FilesystemPath root,
                    java.lang.String userPath,
                    java.lang.String path)

Internal creation of a path for the vfs.

Parameters:

root - the root path (i.e. the cache root)

userPath - the path the application used in the lookup

path - canonical path

Method Detail

setRemoveOnRelease

public void setRemoveOnRelease(boolean remove)

If set, files bumped from the cache are removed from the underlying filesystem.

Parameters:

remove - if true, remove the underlying file on a release.

fsWalk

protected Path fsWalk(java.lang.String userPath,
                      java.util.Map attributes,
                      java.lang.String path)

Looks up the cache entry for a given path.

Overrides:

fsWalk in class FilesystemPath

Parameters:

userPath - the string given by the user in lookup()

attributes - the user's initialization attributes

path - the canonical path name

Returns:

a cache path entry

getScheme

public java.lang.String getScheme()

The scheme for the path is cache:

Overrides:

getScheme in class Path

clear

public void clear()

Clear the memory cache.

exists

public boolean exists()

Returns true if the underlying file exists.

Overrides:

exists in class Path

isDirectory

public boolean isDirectory()

Description copied from class: Path

Tests if the path refers to a directory.

Overrides:

isDirectory in class Path

isFile

public boolean isFile()

Description copied from class: Path

Tests if the path refers to a file.

Overrides:

isFile in class Path

getLength

public long getLength()

Description copied from class: Path

Returns the length of the file in bytes.

Overrides:

getLength in class Path

Following copied from class: com.caucho.vfs.Path

Returns:

0 for non-files

getLastModified

public long getLastModified()

Description copied from class: Path

Returns the last modified time of the file. According to the jdk, this may not correspond to the system time.

Overrides:

getLastModified in class Path

Following copied from class: com.caucho.vfs.Path

Returns:

0 for non-files.

setLastModified

public void setLastModified(long time)

Overrides:

setLastModified in class Path

canRead

public boolean canRead()

Description copied from class: Path

Tests if the file can be read.

Overrides:

canRead in class Path

canWrite

public boolean canWrite()

Description copied from class: Path

Tests if the file can be written.

Overrides:

canWrite in class Path

list

public java.lang.String[] list()
                        throws java.io.IOException

Overrides:

list in class Path

Following copied from class: com.caucho.vfs.Path

Returns:

The contents of this directory or null if the path does not refer to a directory.

mkdir

public boolean mkdir()
              throws java.io.IOException

Description copied from class: Path

Creates the directory named by this path.

Overrides:

mkdir in class Path

Following copied from class: com.caucho.vfs.Path

Returns:

true if successful.

mkdirs

public boolean mkdirs()
               throws java.io.IOException

Description copied from class: Path

Creates the directory named by this path and any parent directories.

Overrides:

mkdirs in class Path

Following copied from class: com.caucho.vfs.Path

Returns:

true if successful.

remove

public boolean remove()
               throws java.io.IOException

Description copied from class: Path

Removes the file or directory named by this path.

Overrides:

remove in class Path

Following copied from class: com.caucho.vfs.Path

Returns:

true if successful.

renameTo

public boolean renameTo(Path path)
                 throws java.io.IOException

Description copied from class: Path

Renames the file or directory to the name given by the path.

Overrides:

renameTo in class Path

Following copied from class: com.caucho.vfs.Path

Returns:

true if successful

writeToStream

public void writeToStream(java.io.OutputStream os)
                   throws java.io.IOException

Write the contents of the cache item to the output stream.

Overrides:

writeToStream in class Path

Parameters:

os - destination output stream.

openReadImpl

public StreamImpl openReadImpl()
                        throws java.io.IOException

Opens a read stream to the path. When the file is in the memory cache, the read stream returns the memory. Otherwise it reads from the backing file.

Overrides:

openReadImpl in class Path

openWriteImpl

public StreamImpl openWriteImpl()
                         throws java.io.IOException

Overrides:

openWriteImpl in class Path

openAppendImpl

public StreamImpl openAppendImpl()
                          throws java.io.IOException

Overrides:

openAppendImpl in class Path

openReadWriteImpl

public StreamImpl openReadWriteImpl()
                             throws java.io.IOException

Overrides:

openReadWriteImpl in class Path

hashCode

public int hashCode()

Returns the hash code, which is based on the underlying file.

Overrides:

hashCode in class FilesystemPath

equals

public boolean equals(java.lang.Object b)

Overrides:

equals in class FilesystemPath