org.apache.batik.ext.awt.image
Class URLImageCache

java.lang.Object
  extended by org.apache.batik.util.SoftReferenceCache
      extended by org.apache.batik.ext.awt.image.URLImageCache

public class URLImageCache
extends SoftReferenceCache

This class manages a cache of soft references to Images that we have already loaded.

Adding an image is two fold. First you add the ParsedURL, this lets the cache know that someone is working on this ParsedURL. Then when the completed RenderedImage is ready you put it into the cache.

If someone requests a ParsedURL after it has been added but before it has been put they will be blocked until the put.


Field Summary
 
Fields inherited from class org.apache.batik.util.SoftReferenceCache
map
 
Constructor Summary
URLImageCache()
          Let people create there own caches.
 
Method Summary
 void clear(ParsedURL purl)
          Clear the entry for ParsedURL.
static URLImageCache getDefaultCache()
           
 boolean isDone(ParsedURL purl)
          Check if request(url) will return immediately with the Filter.
 boolean isPresent(ParsedURL purl)
          Check if request(url) will return with a Filter (not putting you on the hook for it).
 void put(ParsedURL purl, Filter filt)
          Associate bi with purl.
 Filter request(ParsedURL purl)
          If this returns null then you are now 'on the hook'.
 
Methods inherited from class org.apache.batik.util.SoftReferenceCache
clearImpl, flush, isDoneImpl, isPresentImpl, putImpl, requestImpl
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

URLImageCache

public URLImageCache()
Let people create there own caches.

Method Detail

getDefaultCache

public static URLImageCache getDefaultCache()

isPresent

public boolean isPresent(ParsedURL purl)
Check if request(url) will return with a Filter (not putting you on the hook for it). Note that it is possible that this will return true but between this call and the call to request the soft-reference will be cleared. So it is still possible for request to return NULL, just much less likely (you can always call 'clear' in that case).


isDone

public boolean isDone(ParsedURL purl)
Check if request(url) will return immediately with the Filter. Note that it is possible that this will return true but between this call and the call to request the soft-reference will be cleared.


request

public Filter request(ParsedURL purl)
If this returns null then you are now 'on the hook'. to put the Filter associated with ParsedURL into the cache.


clear

public void clear(ParsedURL purl)
Clear the entry for ParsedURL. This is the easiest way to 'get off the hook'. if you didn't indend to get on it.


put

public void put(ParsedURL purl,
                Filter filt)
Associate bi with purl. bi is only referenced through a soft reference so don't rely on the cache to keep it around. If the map no longer contains our purl it was probably cleared or flushed since we were put on the hook for it, so in that case we will do nothing.



Copyright © 2008 Apache Software Foundation. All Rights Reserved.