Package org.eclipse.jface.resource

Class LazyResourceManager

java.lang.Object
org.eclipse.jface.resource.ResourceManager
org.eclipse.jface.resource.LazyResourceManager
@NoReference public class LazyResourceManager extends ResourceManager
A LRU based ResourceManager Wrapper. Not to be used by clients.

  • Constructor Details

    • LazyResourceManager

      public LazyResourceManager(int cacheSize, ResourceManager parent)
      Parameters:
      cacheSize - the lru cache size
      parent - ResourceManager

  • Method Details

    • getDevice

      public Device getDevice()
      Description copied from class: ResourceManager
      Returns the Device for which this ResourceManager will create resources
      Specified by:
      getDevice in class ResourceManager
      Returns:
      the Device associated with this ResourceManager

    • getDefaultImage

      protected Image getDefaultImage()
      Description copied from class: ResourceManager
      Returns the default image that will be returned in the event that the intended image is missing.
      Specified by:
      getDefaultImage in class ResourceManager
      Returns:
      a default image that will be returned in the event that the intended image is missing.

    • create

      public <R> R create(DeviceResourceDescriptor<R> descriptor)
      Description copied from class: ResourceManager
      Returns the resource described by the given descriptor. If the resource already exists, the reference count is incremented and the exiting resource is returned. Otherwise, a new resource is allocated. Every call to this method should have a corresponding call to ResourceManager.destroy(DeviceResourceDescriptor).

      If the resource is intended to live for entire lifetime of this resource-manager, a subsequent call to ResourceManager.destroy(DeviceResourceDescriptor) may be omitted and the resource will be cleaned up when this resource-manager is disposed. This pattern is useful for short-lived LocalResourceManagers, but should never be used with the global resource-manager since doing so effectively leaks the resource.

      The resources returned from this method are reference counted and may be shared internally with other resource-managers. They should never be disposed outside of the ResourceManager framework, or it will cause exceptions in other code that shares them. For example, never call Resource.dispose() on anything returned from this method.

      Specified by:
      create in class ResourceManager
      Parameters:
      descriptor - descriptor for the resource to allocate
      Returns:
      the newly allocated resource (not null)

    • destroy

      public <R> void destroy(DeviceResourceDescriptor<R> descriptor)
      Description copied from class: ResourceManager
      Deallocates a resource previously allocated by ResourceManager.create(DeviceResourceDescriptor). Descriptors are compared by equality, not identity. If the same resource was created multiple times, this may decrement a reference count rather than disposing the actual resource.
      Specified by:
      destroy in class ResourceManager
      Parameters:
      descriptor - identifier for the resource

    • find

      public <R> R find(DeviceResourceDescriptor<R> descriptor)
      Description copied from class: ResourceManager
      Returns a previously allocated resource associated with the given descriptor, or null if none exists yet.
      Specified by:
      find in class ResourceManager
      Parameters:
      descriptor - descriptor to find
      Returns:
      a previously allocated resource for the given descriptor or null if none.