Class ImCache

java.lang.Object

io.github.palexdev.imcache.core.ImCache

public class ImCache
extends Object

Core class which eases communication between the request system (ImRequest) and the caching system (ImgCache).

A single instance of this class should cover most use cases, that's why it offers a 'default' instance via instance(); however, the no-args constructor is left public in case one needs separate caches.

A request is generated starting from the source URL for a certain resource, which is the most generic way to represent a resource; it can be a network resource, a file or something else. Once a request's execution successfully terminates, it asks the associated ImCache instance to save the result, see store(ImRequest, ImImage, ImImage).

While removals are delegated directly to the Cache, get operations should be done by creating a new request. A resource may or may not be cached anymore at a given time. ImRequest uses ImRequest.RequestState.CACHE_HIT to indicate that the resource was found in the cache, and ImRequest.RequestState.SUCCEEDED to indicate that the resource was loaded from its URL. Of course, since ImCache allows getting the ImgCache instance with storage(), you can perform operations directly on the cache data structure, although it's not recommended unless you really need it for your use case.

The last core concept is Transforms. ImCache does not provide only a way to load and cache images, but also a way to modify them via the Transform.transform(BufferedImage) API. Transformations are applied by ImRequest after the original resource is loaded. At that point we can store the results, but this raises a question: which one do you want to save? ImCache allows you to control this behavior by setting the ImCache.StoreStrategy, see store(ImRequest, ImImage, ImImage). /// The reason the system doesn't allow caching both is to save space and for simplicity Most of the time you probably want to cache the original resource, as transform operations are relatively fast.

Defaults & Config

• By default, the store strategy is set to ImCache.StoreStrategy.SAVE_ORIGINAL, can be changed via

invalid reference

#storeStrategy(StoreStrategy)

• By default, this uses an in-memory cache (MemoryCache), can be changed via cacheConfig(Supplier)

See Also:

• ImgCache
• MemoryCache
• DiskCache

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	ImCache.StoreStrategy

Constructor Summary

Constructors

Constructor	Description
ImCache()

Method Summary

Modifier and Type	Method	Description
ImCache	cacheConfig(Supplier<ImgCache<?>> config)	Replaces the current cache with a new one generated by the given config supplier.
ImCache	clear()	Delegates to ImgCache.clear().
ImCache.StoreStrategy	getSaveStrategy()
static ImCache	instance()
boolean	remove(WithID id)	Delegates to remove(WithID).
boolean	remove(String id)	Delegates to ImgCache.remove(String).
ImRequest	request(File file)	Creates a new ImRequest by converting the provided File to a URL with URLHandler.toURL(File).
ImRequest	request(String s)	Creates a new ImRequest by converting the provided string to a URL with URLHandler.toURL(String).
ImRequest	request(URL url)	Creates a new ImRequest with the given URL.
ImRequest	request(Path path)	Delegates to request(File).
ImCache	setStoreStrategy(ImCache.StoreStrategy storeStrategy)	Sets the ImCache.StoreStrategy to be used when saving the result of a request.
ImgCache<?>	storage()
protected void	store(ImRequest request, ImImage src, ImImage out)	Stores a completed request in the cache by its ImRequest.id().

Methods inherited from class java.lang.Object

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

Constructor Details

ImCache

public ImCache()

Method Details

instance

public static ImCache instance()

request

public ImRequest request(URL url)

Creates a new ImRequest with the given URL.

request

public ImRequest request(String s)

Creates a new ImRequest by converting the provided string to a URL with URLHandler.toURL(String).

If the conversion fails, the request will have a null URL.

request

public ImRequest request(File file)

Creates a new ImRequest by converting the provided File to a URL with URLHandler.toURL(File).

If the conversion fails, the request will have a null URL.

request

public ImRequest request(Path path)

Delegates to request(File).

store

protected void store(ImRequest request,
 ImImage src,
 ImImage out)

Stores a completed request in the cache by its ImRequest.id(). The image to be saved is either the original or the transformed one, depending on the ImCache.StoreStrategy.

Note that if no transforms were applied, the src and the out parameters will be the same. In other words, no matter the strategy, the original will be saved.

If the image to be saved is null, nothing happens.

remove

public boolean remove(String id)

Delegates to ImgCache.remove(String).

remove

public boolean remove(WithID id)

Delegates to remove(WithID).

clear

public ImCache clear()

Delegates to ImgCache.clear().

cacheConfig

public ImCache cacheConfig(Supplier<ImgCache<?>> config)

Replaces the current cache with a new one generated by the given config supplier.

Note that the current cache is not cleared automatically.

setStoreStrategy

public ImCache setStoreStrategy(ImCache.StoreStrategy storeStrategy)

Sets the ImCache.StoreStrategy to be used when saving the result of a request.

See Also:

• store(ImRequest, ImImage, ImImage)

storage

public ImgCache<?> storage()

Returns:

the ImgCache instance used by this ImCache to store and retrieve images

getSaveStrategy

public ImCache.StoreStrategy getSaveStrategy()

Returns:

the ImCache.StoreStrategy used by this ImCache to determine which image to save when a request completes successfully

See Also:

• store(ImRequest, ImImage, ImImage)