| java.lang.Object
 net.refractions.udig.ui.ImageCache
| ImageCache | | final public class ImageCache (Code) | | A weakly referenced cache of image descriptors to arrays of image instances
(representing normal, gray and disabled images). This is used to hold images
in memory while their descriptors are defined. When the image descriptors
become weakly referred to, the corresponding images in the array of images
will be disposed.
Weak references of equivalent image descriptors are mapped to the same array
of images (where equivalent descriptors are equals(Object)).
It is recommended to use this class as a singleton, since it creates a thread
for cleaning out images.
It is the responsibility of the user to ensure that the image descriptors are
kept around as long as the images are needed. The users of this cache should
not explicitly dispose the images.
Upon request of a disabled or gray image, the normal image will be created as
well (if it was not already in the cache) in order to create the disabled or
gray version of the image.
This cache makes no guarantees on how long the cleaning process will take, or
when exactly it will occur.
This class may be instantiated; it is not intended to be subclassed.
since:
3.1 |
| Field Summary | |
| final public static int | DISABLE
Types of images supported by the image cache. | | final public static int | GRAY
| | final public static int | REGULAR
|
| Constructor Summary | |
| public | ImageCache()
Constructs a new instance of ImageCache, and starts a
thread to monitor the reference queue for image clean up. | | public | ImageCache(int initialLoadCapacity)
Constructs a new instance of ImageCache, and starts a
thread to monitor the reference queue for image clean up. | | public | ImageCache(int initialLoadCapacity, float loadFactor)
Constructs a new instance of ImageCache, and starts a
thread to monitor the reference queue for image clean up. |
| Method Summary | |
| final public void | dispose()
Cleans up all images in the cache. | | final public Image | getImage(ImageDescriptor imageDescriptor)
Returns the regular image for the given image descriptor. | | final public Image | getImage(ImageDescriptor imageDescriptor, int typeOfImage)
Returns the requested image for the given image descriptor and image
type. | | final public Image | getMissingImage()
Returns the image to display when no image can be found, or none is
specified. |
| DISABLE | | final public static int DISABLE(Code) | | Types of images supported by the image cache.
|
| GRAY | | final public static int GRAY(Code) | | |
| REGULAR | | final public static int REGULAR(Code) | | |
| ImageCache | | public ImageCache()(Code) | | Constructs a new instance of ImageCache, and starts a
thread to monitor the reference queue for image clean up.
|
| ImageCache | | public ImageCache(int initialLoadCapacity)(Code) | | Constructs a new instance of ImageCache, and starts a
thread to monitor the reference queue for image clean up. If the passed
initial load capacity is negative, the image map is created with the
default HashMap constructor.
Parameters:
initialLoadCapacity - Initial load capacity for the image hash map. |
| ImageCache | | public ImageCache(int initialLoadCapacity, float loadFactor)(Code) | | Constructs a new instance of ImageCache, and starts a
thread to monitor the reference queue for image clean up. If the passed
initial load capacity is negative or if the load factor is nonpositive,
the image map is created with the default HashMap
constructor.
Parameters:
initialLoadCapacity - Initial load capacity for the image hash map.
Parameters:
loadFactor - Load factor for the image hash map. |
| dispose | | final public void dispose()(Code) | | Cleans up all images in the cache. This disposes of all of the images,
and drops references to them. This should only be called when the images
and the image cache are no longer needed (i.e.: shutdown). Note that the
image disposal is handled by the cleaner thread.
|
| getImage | | final public Image getImage(ImageDescriptor imageDescriptor)(Code) | | Returns the regular image for the given image descriptor. This caches the
result so that future attempts to get the image for an equivalent or
identical image descriptor will only access the cache. When all
references to equivalent image descriptors are dropped, the images
(regular, gray and disabled) will be cleaned up if they have been
created. This clean up makes no guarantees about how long or when it will
take place.
Parameters:
descriptor - The image descriptor with which a regular image should becreated; may be null. The regular image, either newly created or from the cache. Thisvalue is null if the image descriptor passed in isnull. Note that a missing image will be returnedif a problem occurs in the creation of the image. |
| getImage | | final public Image getImage(ImageDescriptor imageDescriptor, int typeOfImage)(Code) | | Returns the requested image for the given image descriptor and image
type. This caches the result so that future attempts to get the image for
an equivalent or identical image descriptor will only access the cache.
When all references to equivalent image descriptors are dropped, the
images (regular, gray and disabled) will be cleaned up if they have been
created. This clean up makes no guarantees about how long or when it will
take place.
Parameters:
descriptor - The image descriptor with which the requested image should becreated; may be null.
Parameters:
typeOfImage - The type of the desired image:ImageCache.DISABLED,ImageCache.GRAY orImageCache.NORMAL. The image for the requested image type, either newly created orfrom the cache. This value is null if the imagedescriptor passed in is null, or if the imagetype is invalid. Note that a missing image will be returned if aproblem occurs in the creation of the image. |
| getMissingImage | | final public Image getMissingImage()(Code) | | Returns the image to display when no image can be found, or none is
specified. This image is only disposed when the cache is disposed.
The image to display for missing images. This value will never benull. |
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