Package org.jclouds.compute.suppliers

Class ImageCacheSupplier

java.lang.Object

org.jclouds.compute.suppliers.ImageCacheSupplier

All Implemented Interfaces:

com.google.common.base.Supplier<Set<? extends Image>>, Supplier<Set<? extends Image>>, ValueLoadedCallback<Set<? extends Image>>

@Beta
public class ImageCacheSupplier
extends Object
implements com.google.common.base.Supplier<Set<? extends Image>>, ValueLoadedCallback<Set<? extends Image>>

Memoized image supplier that allows new images to be registered at runtime.

The memoized Supplierinvalid input: '<'Setinvalid input: '<'? extends Image>> is a static data structure that can't be properly modified at runtime. This class is a wrapper for the image supplier to provide a way to register new images as needed. Once a new image is created by the ImageExtension, or discovered by other means (see https://issues.apache.org/jira/browse/JCLOUDS-570) this supplier will allow the image to be appended to the cached list.

Nested Class Summary

Nested classes/interfaces inherited from interface org.jclouds.rest.suppliers.ValueLoadedCallback

ValueLoadedCallback.NoOpCallback<V>

Field Summary

Fields

Modifier and Type	Field	Description
protected Logger	logger

Constructor Summary

Constructors

Constructor	Description
ImageCacheSupplier(com.google.common.base.Supplier<Set<? extends Image>> imageSupplier, long sessionIntervalSeconds, AtomicReference<AuthorizationException> authException, com.google.inject.Provider<GetImageStrategy> imageLoader)

Method Summary

Modifier and Type	Method	Description
Set<? extends Image>	get()
com.google.common.base.Optional<? extends Image>	get(String id)	Loads an image by id.
Set<? extends Image>	rebuildCache()	Calls the liveImageSupplier to get the current images and rebuilds the cache with them.
void	registerImage(Image image)	Registers a new image in the image cache.
void	removeImage(String imageId)	Removes an image from the image cache.
void	reset(Set<? extends Image> images)	Resets the cache to the given set of images.
void	valueLoaded(com.google.common.base.Optional<Set<? extends Image>> value)	The cache is subscribed to value loading events generated by the MemoizedRetryOnTimeOutButNotOnAuthorizationExceptionSupplier.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

logger

@Named("jclouds.compute")
protected Logger logger

Constructor Details

ImageCacheSupplier

public ImageCacheSupplier(com.google.common.base.Supplier<Set<? extends Image>> imageSupplier,
 long sessionIntervalSeconds,
 AtomicReference<AuthorizationException> authException,
 com.google.inject.Provider<GetImageStrategy> imageLoader)

Method Details

get

public Set<? extends Image> get()

Specified by:

get in interface com.google.common.base.Supplier<Set<? extends Image>>

Specified by:

get in interface Supplier<Set<? extends Image>>

valueLoaded

public void valueLoaded(com.google.common.base.Optional<Set<? extends Image>> value)

The cache is subscribed to value loading events generated by the MemoizedRetryOnTimeOutButNotOnAuthorizationExceptionSupplier.

Every time the memoized supplier reloads a value, an event will be populated and this method will handle it. This makes it possible to refresh the cache with the last values everytime they are reloaded.

Specified by:

valueLoaded in interface ValueLoadedCallback<Set<? extends Image>>

reset

public void reset(Set<? extends Image> images)

Resets the cache to the given set of images.

This method is called when the memoized image supplier is reloaded, or when the cache needs to be refreshed (for example when the TempalteBuilder is invoked forcing a fresh image lookup.

rebuildCache

public Set<? extends Image> rebuildCache()

Calls the liveImageSupplier to get the current images and rebuilds the cache with them.

get

public com.google.common.base.Optional<? extends Image> get(String id)

Loads an image by id.

This methods returns the cached image, or performs a call to retrieve it if the image is still not cached.

registerImage

public void registerImage(Image image)

Registers a new image in the image cache.

This method should be called to register new images into the image cache when some image that is known to exist in the provider is still not cached. For example, this can happen when an image is created after the image cache has been populated for the first time.

Note that this method does not check if the image is already cached, to avoid loading all images if the image cache is still not populated.

Parameters:

image - The image to be registered to the cache.

removeImage

public void removeImage(String imageId)

Removes an image from the image cache.

This method should be called to invalidate an already cached image, when some image known to not exist in the provider is still cached.

Parameters:

imageId - The id of the image to invalidate.