com.purpletech.io
Class FileCache

java.lang.Object
  |
  +--com.purpletech.io.FileCache

public class FileCache

extends java.lang.Object

Maintains a cache of files on disk.

Nested Class Summary

protected class	FileCache.DefaultFetcher
static class	FileCache.Error
static interface	FileCache.Fetcher

Constructor Summary

FileCache(java.lang.String dir)

FileCache(java.lang.String dir, long msec)

Method Summary

static void	debug(java.lang.String x)
java.io.File	get(java.lang.String source) Takes an http: URL, a file: URL, or a raw file system pathname.
java.io.File	get(java.lang.String source, FileCache.Fetcher fetcher)
FileCache.Fetcher	getDefaultFetcher()
FileCache.Error	getError(java.lang.String source)
static boolean	isDiff(java.io.File a, java.io.File b)
static boolean	isDiff(java.io.InputStream a, java.io.InputStream b)
static void	main(java.lang.String[] args)
static java.lang.String	mapName(java.lang.String in) convert a name to a filesystem-safe name.
void	setAllowEmpty(boolean allow) do we allow empty files to replace non-empty cache files?
void	setAllowLocal(boolean allow) do we allow local file access or just HTTP?
void	setCacheDir(java.lang.String dirname)
static void	setDebug(boolean f)
void	setDownloadTimeout(long msec) number of milliseconds we attempt to download something before failing
protected void	setError(java.lang.String source, java.lang.Throwable exception)
void	setTimeout(long msec) number of milliseconds we keep something in the cache before refetching

Methods inherited from class java.lang.Object

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

Constructor Detail

FileCache

public FileCache(java.lang.String dir)
          throws java.io.IOException

FileCache

public FileCache(java.lang.String dir,
                 long msec)
          throws java.io.IOException

Method Detail

setDebug

public static void setDebug(boolean f)

setCacheDir

public void setCacheDir(java.lang.String dirname)
                 throws java.io.IOException

java.io.IOException

setAllowLocal

public void setAllowLocal(boolean allow)

do we allow local file access or just HTTP?

setAllowEmpty

public void setAllowEmpty(boolean allow)

do we allow empty files to replace non-empty cache files?

setTimeout

public void setTimeout(long msec)

number of milliseconds we keep something in the cache before refetching

setDownloadTimeout

public void setDownloadTimeout(long msec)

number of milliseconds we attempt to download something before failing

getDefaultFetcher

public FileCache.Fetcher getDefaultFetcher()

get

public java.io.File get(java.lang.String source)

Takes an http: URL, a file: URL, or a raw file system pathname. Returns a file, whose LastModified date represents the last time it was downloaded and was new.

Is not thread-safe. Todo: make a thread-safe Map of currently-downloading files. Compare the source to the contents of that map and block until it's free. Then when it comes out it will check the timestamp and probably notice that it was just downloaded.

get

public java.io.File get(java.lang.String source,
                        FileCache.Fetcher fetcher)

mapName

public static java.lang.String mapName(java.lang.String in)

convert a name to a filesystem-safe name. The current algorithm is a little flawed, and will occasionally map two files to the same name. This should be fixed.

isDiff

public static boolean isDiff(java.io.File a,
                             java.io.File b)
                      throws java.io.IOException

java.io.IOException

isDiff

public static boolean isDiff(java.io.InputStream a,
                             java.io.InputStream b)
                      throws java.io.IOException

java.io.IOException

debug

public static void debug(java.lang.String x)

getError

public FileCache.Error getError(java.lang.String source)

setError

protected void setError(java.lang.String source,
                        java.lang.Throwable exception)

main

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

java.io.IOException