Cache

java.lang.Object
- org.apache.pekko.http.caching.scaladsl.Cache<K,V>

All Implemented Interfaces:

Cache<K,V>

Direct Known Subclasses:

LfuCache
```
public abstract class Cache<K,V>
extends java.lang.Object
implements Cache<K,V>
```
API MAY CHANGE
General interface implemented by all cache implementations.

Constructor Summary

Constructors
Constructor and Description

Cache()

Constructors
Constructor and Description
`Cache()`

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`abstract scala.concurrent.Future<V>`	`apply(K key, scala.Function0<scala.concurrent.Future<V>> genValue)` Returns either the cached Future for the given key or evaluates the given value generating function producing a `Future[V]`.
`scala.concurrent.Future<V>`	`apply(K key, scala.Function1<scala.concurrent.Promise<V>,scala.runtime.BoxedUnit> f)` Returns either the cached Future for the key or evaluates the given function which should lead to eventual completion of the promise.
`abstract void`	`clear()` Clears the cache by removing all entries.
`abstract scala.Option<scala.concurrent.Future<V>>`	`get(K key)` Retrieves the future instance that is currently in the cache for the given key.
`scala.concurrent.Future<V>`	`get(K key, scala.Function0<V> block)` Returns either the cached Future for the given key or the given value as a Future
`java.util.concurrent.CompletionStage<V>`	`getFuture(K key, org.apache.pekko.japi.Creator<java.util.concurrent.CompletionStage<V>> genValue)` Returns either the cached CompletionStage for the given key or evaluates the given value generating function producing a `CompletionStage`.
`java.util.Set<K>`	`getKeys()` Returns the set of keys in the cache, in no particular order Should return in roughly constant time.
`java.util.Optional<java.util.concurrent.CompletionStage<V>>`	`getOptional(K key)` Retrieves the CompletionStage instance that is currently in the cache for the given key.
`java.util.concurrent.CompletionStage<V>`	`getOrCreateStrict(K key, org.apache.pekko.japi.Creator<V> block)` Returns either the cached CompletionStage for the given key or the given value as a CompletionStage
`java.util.concurrent.CompletionStage<V>`	`getOrFulfil(K key, org.apache.pekko.japi.Procedure<java.util.concurrent.CompletableFuture<V>> f)` Returns either the cached `CompletionStage` for the key, or evaluates the given function which should lead to eventual completion of the completable future.
`abstract scala.concurrent.Future<V>`	`getOrLoad(K key, scala.Function1<K,scala.concurrent.Future<V>> loadValue)` Returns either the cached Future for the given key, or applies the given value loading function on the key, producing a `Future[V]`.
`abstract scala.collection.immutable.Set<K>`	`keys()` Returns the set of keys in the cache, in no particular order Should return in roughly constant time.
`abstract scala.concurrent.Future<V>`	`put(K key, scala.concurrent.Future<V> mayBeValue, scala.concurrent.ExecutionContext ex)` Cache the given future if not cached previously.
`abstract void`	`remove(K key)` Removes the cache item for the given key.
`abstract int`	`size()` Returns the upper bound for the number of currently cached entries.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - Cache
```
public Cache()
```
- Method Detail
  - apply
```
public abstract scala.concurrent.Future<V> apply(K key,
                                                 scala.Function0<scala.concurrent.Future<V>> genValue)
```
    Returns either the cached Future for the given key or evaluates the given value generating function producing a Future[V].
    
    Parameters:
    
    key - (undocumented)
    
    genValue - (undocumented)
    
    Returns:
    
    (undocumented)
  - apply
```
public scala.concurrent.Future<V> apply(K key,
                                        scala.Function1<scala.concurrent.Promise<V>,scala.runtime.BoxedUnit> f)
```
    Returns either the cached Future for the key or evaluates the given function which should lead to eventual completion of the promise.
    
    Parameters:
    
    key - (undocumented)
    
    f - (undocumented)
    
    Returns:
    
    (undocumented)
  - clear
```
public abstract void clear()
```
    Clears the cache by removing all entries.
    
    Specified by:
    
    clear in interface Cache<K,V>
  - get
```
public scala.concurrent.Future<V> get(K key,
                                      scala.Function0<V> block)
```
    Returns either the cached Future for the given key or the given value as a Future
    
    Parameters:
    
    key - (undocumented)
    
    block - (undocumented)
    
    Returns:
    
    (undocumented)
  - get
```
public abstract scala.Option<scala.concurrent.Future<V>> get(K key)
```
    Retrieves the future instance that is currently in the cache for the given key. Returns None if the key has no corresponding cache entry.
    
    Parameters:
    
    key - (undocumented)
    
    Returns:
    
    (undocumented)
  - getFuture
```
public final java.util.concurrent.CompletionStage<V> getFuture(K key,
                                                               org.apache.pekko.japi.Creator<java.util.concurrent.CompletionStage<V>> genValue)
```
    Description copied from interface: Cache
    
    Returns either the cached CompletionStage for the given key or evaluates the given value generating function producing a `CompletionStage`.
    
    Specified by:
    
    getFuture in interface Cache<K,V>
  - getKeys
```
public java.util.Set<K> getKeys()
```
    Description copied from interface: Cache
    
    Returns the set of keys in the cache, in no particular order Should return in roughly constant time. Note that this number might not reflect the exact keys of active, unexpired cache entries, since expired entries are only evicted upon next access (or by being thrown out by a capacity constraint).
    
    Specified by:
    
    getKeys in interface Cache<K,V>
  - getOptional
```
public java.util.Optional<java.util.concurrent.CompletionStage<V>> getOptional(K key)
```
    Description copied from interface: Cache
    
    Retrieves the CompletionStage instance that is currently in the cache for the given key. Returns None if the key has no corresponding cache entry.
    
    Specified by:
    
    getOptional in interface Cache<K,V>
  - getOrCreateStrict
```
public java.util.concurrent.CompletionStage<V> getOrCreateStrict(K key,
                                                                 org.apache.pekko.japi.Creator<V> block)
```
    Returns either the cached CompletionStage for the given key or the given value as a CompletionStage
    
    Specified by:
    
    getOrCreateStrict in interface Cache<K,V>
    
    Parameters:
    
    key - (undocumented)
    
    block - (undocumented)
    
    Returns:
    
    (undocumented)
  - getOrFulfil
```
public final java.util.concurrent.CompletionStage<V> getOrFulfil(K key,
                                                                 org.apache.pekko.japi.Procedure<java.util.concurrent.CompletableFuture<V>> f)
```
    Description copied from interface: Cache
    
    Returns either the cached CompletionStage for the key, or evaluates the given function which should lead to eventual completion of the completable future.
    
    Specified by:
    
    getOrFulfil in interface Cache<K,V>
  - getOrLoad
```
public abstract scala.concurrent.Future<V> getOrLoad(K key,
                                                     scala.Function1<K,scala.concurrent.Future<V>> loadValue)
```
    Returns either the cached Future for the given key, or applies the given value loading function on the key, producing a Future[V].
    
    Parameters:
    
    key - (undocumented)
    
    loadValue - (undocumented)
    
    Returns:
    
    (undocumented)
  - keys
```
public abstract scala.collection.immutable.Set<K> keys()
```
    Returns the set of keys in the cache, in no particular order Should return in roughly constant time. Note that this number might not reflect the exact keys of active, unexpired cache entries, since expired entries are only evicted upon next access (or by being thrown out by a capacity constraint).
    
    Returns:
    
    (undocumented)
  - put
```
public abstract scala.concurrent.Future<V> put(K key,
                                               scala.concurrent.Future<V> mayBeValue,
                                               scala.concurrent.ExecutionContext ex)
```
    Cache the given future if not cached previously. Or replace the old cached value on successful completion of given future. In case the given future fails, the previously cached value for that key (if any) will remain unchanged.
    
    Parameters:
    
    key - (undocumented)
    
    mayBeValue - (undocumented)
    
    ex - (undocumented)
    
    Returns:
    
    (undocumented)
  - remove
```
public abstract void remove(K key)
```
    Removes the cache item for the given key.
    
    Specified by:
    
    remove in interface Cache<K,V>
    
    Parameters:
    
    key - (undocumented)
  - size
```
public abstract int size()
```
    Returns the upper bound for the number of currently cached entries. Note that this number might not reflect the exact number of active, unexpired cache entries, since expired entries are only evicted upon next access (or by being thrown out by a capacity constraint).
    
    Specified by:
    
    size in interface Cache<K,V>
    
    Returns:
    
    (undocumented)

Class Cache<K,V>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Cache

Method Detail

apply

apply

clear

get

get

getFuture

getKeys

getOptional

getOrCreateStrict

getOrFulfil

getOrLoad

keys

put

remove

size