Class ResourceTracker

java.lang.Object
net.adoptopenjdk.icedteaweb.resources.ResourceTracker
public class ResourceTracker extends Object
This class tracks the downloading of various resources of a JNLP file to local files in the cache. It can be used to download icons, jnlp and extension files, jars, and jardiff files using the version based protocol or any file using the basic download protocol (jardiff and version not implemented yet).

The resource tracker can be configured to prefetch resources, which are downloaded in the order added to the media tracker.

Multiple threads are used to download and cache resources that are actively being waited for (blocking a caller) or those that have been started downloading by calling the startDownload method. Resources that are prefetched are downloaded one at a time and only if no other trackers have requested downloads. This allows the tracker to start downloading many items without using many system resources, but still quickly download items as needed.

Version:
$Revision: 1.22 $

  • Field Details

    • LOG

      private static final Logger LOG

    • resources

      private final Map<UrlKey,Resource> resources
      the resources known about by this resource tracker

    • prefetch

      private final boolean prefetch
      whether to download parts before requested

    • downloadOptions

      private final DownloadOptions downloadOptions

    • updatePolicy

      private final UpdatePolicy updatePolicy

  • Constructor Details

    • ResourceTracker

      public ResourceTracker()
      Creates a resource tracker that does not prefetch resources.

    • ResourceTracker

      public ResourceTracker(boolean prefetch)
      Creates a resource tracker that does not prefetch resources.

    • ResourceTracker

      public ResourceTracker(boolean prefetch, DownloadOptions downloadOptions, UpdatePolicy updatePolicy)
      Creates a resource tracker.
      Parameters:
      prefetch - whether to download resources before requested.

  • Method Details

    • addResource

      public void addResource(URL location, VersionString version)

    • addResource

      public void addResource(URL location, VersionString version, UpdatePolicy updatePolicy)
      Add a resource identified by the specified location and version. The tracker only downloads one version of a given resource per instance (ie cannot download both versions 1 and 2 of a resource in the same tracker).
      Parameters:
      location - the location of the resource
      version - the resource version
      updatePolicy - whether to check for updates if already in cache

    • addToResources

      private boolean addToResources(Resource resource)
      Returns:
      true if no resource with the given URL is currently tracked.

    • startDownloadingIfPrefetch

      private void startDownloadingIfPrefetch(Resource resource)

    • removeResource

      public void removeResource(URL location)
      Removes a resource from the tracker. This method is useful to allow memory to be reclaimed, but calling this method is not required as resources are reclaimed when the tracker is collected.
      Parameters:
      location - location of resource to be removed
      Throws:
      IllegalResourceDescriptorException - if the resource is not being tracked

    • getCacheURL

      public URL getCacheURL(URL location)
      Returns a URL pointing to the cached location of the resource, or the resource itself if it is a non-cacheable resource.

      If the resource has not downloaded yet, the method will block until it has been transferred to the cache.

      Parameters:
      location - the resource location
      Returns:
      the resource, or null if it could not be downloaded
      Throws:
      IllegalResourceDescriptorException - if the resource is not being tracked
      See Also:

    • getCacheFile

      public File getCacheFile(URL location)
      Returns a file containing the downloaded resource. If the resource is non-cacheable then null is returned unless the resource is a local file (the original file is returned).

      If the resource has not downloaded yet, the method will block until it has been transferred to the cache.

      Parameters:
      location - the resource location
      Returns:
      a local file containing the resource, or null
      Throws:
      IllegalResourceDescriptorException - if the resource is not being tracked
      See Also:

    • getCacheFile

      private static File getCacheFile(Resource resource)

    • waitForResources

      public void waitForResources(URL... urls) throws InterruptedException
      Wait for a group of resources to be downloaded and made available locally.
      Parameters:
      urls - the resources to wait for
      Throws:
      InterruptedException - if thread is interrupted
      IllegalResourceDescriptorException - if the resource is not being tracked

    • getAmountRead

      public long getAmountRead(URL location)
      Returns the number of bytes downloaded for a resource.
      Parameters:
      location - the resource location
      Returns:
      the number of bytes transferred
      Throws:
      IllegalResourceDescriptorException - if the resource is not being tracked

    • checkResource

      public boolean checkResource(URL location)
      Returns whether a resource is available for use (ie, can be accessed with the getCacheFile method).
      Parameters:
      location - the resource location
      Returns:
      resource availability
      Throws:
      IllegalResourceDescriptorException - if the resource is not being tracked

    • getTotalSize

      public long getTotalSize(URL location)
      Returns the number of total size in bytes of a resource, or -1 it the size is not known.
      Parameters:
      location - the resource location
      Returns:
      the number of bytes, or -1
      Throws:
      IllegalResourceDescriptorException - if the resource is not being tracked

    • getResources

      private Resource[] getResources(URL[] urls)

    • getResource

      private Resource getResource(URL location)
      Return the resource matching the specified URL.
      Throws:
      IllegalResourceDescriptorException - if the resource is not being tracked

    • waitForCompletion

      private void waitForCompletion(Resource... resources)
      Wait for some resources.
      Parameters:
      resources - the resources to wait for
      Throws:
      InterruptedException - if another thread interrupted the wait

    • getConfiguredThreadCount

      private int getConfiguredThreadCount()

    • triggerDownloadFor

      private Future<Resource> triggerDownloadFor(Resource resource, Executor downloadExecutor)

    • addDownloadListener

      public void addDownloadListener(URL resourceUrl, URL[] allResources, DownloadServiceListener listener)

    • getPercentageDownloaded

      private int getPercentageDownloaded(URL[] allResources)