public class ImageCache
extends java.lang.Object
Don't use one ImageCache instance in the context of multiple base URIs because relative URIs would not work correctly anymore.
By default, the URIs of inaccessible images are remembered but these entries are discarded after 60 seconds (which causes a retry next time the same URI is requested). This allows to counteract performance loss when accessing invalid or temporarily unavailable images over slow connections.
Modifier and Type | Field and Description |
---|---|
protected static org.apache.commons.logging.Log |
log
logger
|
Constructor and Description |
---|
ImageCache()
Default constructor with default settings.
|
ImageCache(org.apache.xmlgraphics.image.loader.cache.TimeStampProvider timeStampProvider,
ExpirationPolicy invalidURIExpirationPolicy)
Constructor for customized behaviour and testing.
|
Modifier and Type | Method and Description |
---|---|
void |
clearCache()
Clears the image cache (all ImageInfo and Image objects).
|
void |
doHouseKeeping()
Triggers some house-keeping, i.e.
|
Image |
getImage(ImageInfo info,
ImageFlavor flavor)
Returns an image from the cache or null if it wasn't found.
|
Image |
getImage(java.lang.String uri,
ImageFlavor flavor)
Returns an image from the cache or null if it wasn't found.
|
protected ImageInfo |
getImageInfo(java.lang.String uri)
Returns an ImageInfo instance from the cache or null if none is found.
|
boolean |
isInvalidURI(java.lang.String uri)
Indicates whether a URI has previously been identified as an invalid URI.
|
ImageInfo |
needImageInfo(java.lang.String uri,
ImageSessionContext session,
ImageManager manager)
Returns an ImageInfo instance for a given URI.
|
void |
putImage(Image img)
Registers an image with the cache.
|
protected void |
putImageInfo(ImageInfo info)
Registers an ImageInfo instance with the cache.
|
void |
setCacheListener(ImageCacheListener listener)
Sets an ImageCacheListener instance so the events in the image cache can be observed.
|
public ImageCache()
public ImageCache(org.apache.xmlgraphics.image.loader.cache.TimeStampProvider timeStampProvider, ExpirationPolicy invalidURIExpirationPolicy)
timeStampProvider
- the time stamp provider to useinvalidURIExpirationPolicy
- the expiration policy for invalid URIspublic void setCacheListener(ImageCacheListener listener)
listener
- the listener instancepublic ImageInfo needImageInfo(java.lang.String uri, ImageSessionContext session, ImageManager manager) throws ImageException, java.io.IOException
uri
- the image's URIsession
- the session contextmanager
- the ImageManager handling the imagesImageException
- if an error occurs while parsing image datajava.io.IOException
- if an I/O error occurs while loading image datapublic boolean isInvalidURI(java.lang.String uri)
uri
- the image's URIprotected ImageInfo getImageInfo(java.lang.String uri)
uri
- the image's URIprotected void putImageInfo(ImageInfo info)
info
- the ImageInfo instancepublic Image getImage(ImageInfo info, ImageFlavor flavor)
info
- the ImageInfo instance representing the imageflavor
- the requested ImageFlavor for the imagepublic Image getImage(java.lang.String uri, ImageFlavor flavor)
uri
- the image's URIflavor
- the requested ImageFlavor for the imagepublic void putImage(Image img)
img
- the imagepublic void clearCache()
public void doHouseKeeping()
Copyright 1999-2012 The Apache Software Foundation. All Rights Reserved.