pt.ua.dicoogle.server.web.utils

Class LocalImageCache

java.lang.Object

java.lang.Thread

pt.ua.dicoogle.server.web.utils.LocalImageCache

All Implemented Interfaces:

java.lang.Runnable, ImageRetriever

public class LocalImageCache
extends java.lang.Thread
implements ImageRetriever

Handles the caching of PNG images generated by the Image Servlet. The cached images are kept inside a temporary directory created inside the user (or system) temporary directory. These are maintained for a maximum period of time if they are not used, and deleted on a regular basis to save disk space while not hurting the cache performance.

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

java.lang.Thread.State, java.lang.Thread.UncaughtExceptionHandler

Field Summary

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor and Description
LocalImageCache(java.lang.String name, int interval, int maxAge, ImageRetriever under) Creates a local image cache that pools its cache directory at interval rates and deletes files older than maxAge.

Method Summary

Modifier and Type	Method and Description
java.io.InputStream	get(java.net.URI uri, int frameNumber, boolean thumbnail) Obtain an image by URI.
int	getInterval()
int	getMaxAge()
boolean	isRunning()
void	run()
void	setInterval(int interval)
void	setMaxAge(int maxAge)
void	start()
void	terminate() Stop this cache from checking for old files.
protected static java.lang.String	toFileName(java.lang.String imageUri, int frameNumber, boolean thumbnail)

Methods inherited from class java.lang.Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Constructor Detail

LocalImageCache

public LocalImageCache(java.lang.String name,
                       int interval,
                       int maxAge,
                       ImageRetriever under)

Creates a local image cache that pools its cache directory at interval rates and deletes files older than maxAge.

Parameters:

name - the name of the cache directory.

interval - the number of seconds to wait between pool cache directory pooling.

maxAge - the number of seconds that a file can stay in the cache without being used/read.

under - the underlying image retriever

Method Detail

start

public void start()

Overrides:

start in class java.lang.Thread

run

public void run()

Specified by:

run in interface java.lang.Runnable

Overrides:

run in class java.lang.Thread

terminate

public void terminate()

Stop this cache from checking for old files.

getInterval

public int getInterval()

Returns:

the interval

setInterval

public void setInterval(int interval)

Parameters:

interval - the interval to set

getMaxAge

public int getMaxAge()

Returns:

the maxAge

setMaxAge

public void setMaxAge(int maxAge)

Parameters:

maxAge - the maxAge to set

toFileName

protected static java.lang.String toFileName(java.lang.String imageUri,
                                             int frameNumber,
                                             boolean thumbnail)

get

public java.io.InputStream get(java.net.URI uri,
                               int frameNumber,
                               boolean thumbnail)
                        throws java.io.IOException

Description copied from interface: ImageRetriever

Obtain an image by URI.

Specified by:

get in interface ImageRetriever

Parameters:

uri - the URI to the image

frameNumber - the frame number

thumbnail - whether to retrieve a thumbnail (true) or the image in its original size (false)

Returns:

an input stream for retrieving the image's content

Throws:

java.io.IOException

isRunning

public boolean isRunning()

Returns:

if the caching mechanism for checking and removing old/un-used cache files is still running