Spring Framework 6.1.4 · org.springframework.cache.Cache

Modifier and Type	Class and Description
public static class	Cache.ValueRetrievalException Wrapper exception to be thrown from `get(Object, Callable)` in case of the value loader callback failing with an exception.
public static interface	Cache.ValueWrapper A (wrapper) object representing a cache value.

Method Summary

Modifier and Type	Method and Description
public void	clear() Clear the cache through removing all mappings.
public void	evict(Object the key whose mapping is to be removed from the cache key) Evict the mapping for this key from this cache if it is present.
public default boolean	Returns: `true` if the cache was known to have a mapping for this key before, `false` if it did not (or if prior presence could not be determined) evictIfPresent(Object the key whose mapping is to be removed from the cache key) Evict the mapping for this key from this cache if it is present, expecting the key to be immediately invisible for subsequent lookups.
public Cache.ValueWrapper	Returns: the value to which this cache maps the specified key, contained within a `ValueWrapper` which may also hold a cached `null` value. A straight `null` being returned means that the cache contains no mapping for this key. get(Object the key whose associated value is to be returned key) Return the value to which this cache maps the specified key.
public <T> T	Returns: the value to which this cache maps the specified key (which may be `null` itself), or also `null` if the cache contains no mapping for this key get(Object the key whose associated value is to be returned key, Class<T> the required type of the returned value (may be `null` to bypass a type check; in case of a `null` value found in the cache, the specified type is irrelevant) type) Return the value to which this cache maps the specified key, generically specifying a type that return value will be cast to.
public <T> T	Returns: the value to which this cache maps the specified key get(Object the key whose associated value is to be returned key, Callable<T> valueLoader) Return the value to which this cache maps the specified key, obtaining that value from `valueLoader` if necessary.
public String	getName() Return the cache name.
public Object	getNativeCache() Return the underlying native cache provider.
public default boolean	Returns: `true` if the cache was known to have mappings before, `false` if it did not (or if prior presence of entries could not be determined) invalidate() Invalidate the cache through removing all mappings, expecting all entries to be immediately invisible for subsequent lookups.
public void	put(Object the key with which the specified value is to be associated key, Object the value to be associated with the specified key value) Associate the specified value with the specified key in this cache.
public default Cache.ValueWrapper	Returns: the value to which this cache maps the specified key (which may be `null` itself), or also `null` if the cache did not contain any mapping for that key prior to this call. Returning `null` is therefore an indicator that the given `value` has been associated with the key. putIfAbsent(Object the key with which the specified value is to be associated key, Object the value to be associated with the specified key value) Atomically associate the specified value with the specified key in this cache if it is not set already.
public default CompletableFuture<?>	Returns: the value to which this cache maps the specified key, contained within a `CompletableFuture` which may also be empty when a cache miss has been late-determined. A straight `null` being returned means that the cache immediately determined that it contains no mapping for this key. A `ValueWrapper` contained within the `CompletableFuture` indicates a cached value that is potentially `null`; this is sensible in a late-determined scenario where a regular CompletableFuture-contained `null` indicates a cache miss. However, a cache may also return a plain value if it does not support the actual caching of `null` values, avoiding the extra level of value wrapping. Spring's cache processing can deal with all such implementation strategies. retrieve(Object the key whose associated value is to be returned key) Return the value to which this cache maps the specified key, wrapped in a `CompletableFuture`.
public default <T> CompletableFuture<T>	Returns: the value to which this cache maps the specified key, contained within a `CompletableFuture` which will never be `null`. The provided future is expected to produce a value or raise an exception. retrieve(Object the key whose associated value is to be returned key, Supplier<CompletableFuture<T>> valueLoader) Return the value to which this cache maps the specified key, obtaining that value from `valueLoader` if necessary.

Method Detail

clear back to summary

clear	back to summary
public void clear() Clear the cache through removing all mappings. Actual clearing may be performed in an asynchronous or deferred fashion, with subsequent lookups possibly still seeing the entries. This may for example be the case with transactional cache decorators. Use `invalidate()` for guaranteed immediate removal of entries. If the cache is supposed to be compatible with `CompletableFuture` and reactive interactions, the clear operation needs to be effectively non-blocking, with any backend write-through happening asynchronously. This goes along with a cache implemented and configured to support `retrieve(Object)` and `retrieve(Object, Supplier)`. See Also `invalidate()`

public void clear()

Clear the cache through removing all mappings.

Actual clearing may be performed in an asynchronous or deferred fashion, with subsequent lookups possibly still seeing the entries. This may for example be the case with transactional cache decorators. Use invalidate() for guaranteed immediate removal of entries.

If the cache is supposed to be compatible with CompletableFuture and reactive interactions, the clear operation needs to be effectively non-blocking, with any backend write-through happening asynchronously. This goes along with a cache implemented and configured to support retrieve(Object) and retrieve(Object, Supplier).

See Also: invalidate()

evict back to summary

evict	back to summary
public void evict(Object key) Evict the mapping for this key from this cache if it is present. Actual eviction may be performed in an asynchronous or deferred fashion, with subsequent lookups possibly still seeing the entry. This may for example be the case with transactional cache decorators. Use `evictIfPresent` for guaranteed immediate removal. If the cache is supposed to be compatible with `CompletableFuture` and reactive interactions, the evict operation needs to be effectively non-blocking, with any backend write-through happening asynchronously. This goes along with a cache implemented and configured to support `retrieve(Object)` and `retrieve(Object, Supplier)`. Parameters key:Object the key whose mapping is to be removed from the cache See Also `evictIfPresent(Object)`

public void evict(Object key)

Evict the mapping for this key from this cache if it is present.

Actual eviction may be performed in an asynchronous or deferred fashion, with subsequent lookups possibly still seeing the entry. This may for example be the case with transactional cache decorators. Use evictIfPresent for guaranteed immediate removal.

If the cache is supposed to be compatible with CompletableFuture and reactive interactions, the evict operation needs to be effectively non-blocking, with any backend write-through happening asynchronously. This goes along with a cache implemented and configured to support retrieve(Object) and retrieve(Object, Supplier).

Parameters

key:Object: the key whose mapping is to be removed from the cache

See Also

evictIfPresent(Object)

evictIfPresent back to summary

evictIfPresent	back to summary
public default boolean evictIfPresent(Object key) Evict the mapping for this key from this cache if it is present, expecting the key to be immediately invisible for subsequent lookups. The default implementation delegates to `evict(Object)`, returning `false` for not-determined prior presence of the key. Cache providers and in particular cache decorators are encouraged to perform immediate eviction if possible (e.g. in case of generally deferred cache operations within a transaction) and to reliably determine prior presence of the given key. Parameters key:Object the key whose mapping is to be removed from the cache Returns:boolean `true` if the cache was known to have a mapping for this key before, `false` if it did not (or if prior presence could not be determined) Since 5.2 See Also `evict(Object)`

public default boolean evictIfPresent(Object key)

Evict the mapping for this key from this cache if it is present, expecting the key to be immediately invisible for subsequent lookups.

The default implementation delegates to evict(Object), returning false for not-determined prior presence of the key. Cache providers and in particular cache decorators are encouraged to perform immediate eviction if possible (e.g. in case of generally deferred cache operations within a transaction) and to reliably determine prior presence of the given key.

Parameters

key:Object: the key whose mapping is to be removed from the cache

Returns:boolean

true if the cache was known to have a mapping for this key before, false if it did not (or if prior presence could not be determined)

Since

5.2

See Also

evict(Object)

get back to summary

get	back to summary
public Cache.ValueWrapper get(Object key) Return the value to which this cache maps the specified key. Returns `null` if the cache contains no mapping for this key; otherwise, the cached value (which may be `null` itself) will be returned in a `ValueWrapper`. Parameters key:Object the key whose associated value is to be returned Returns:Cache.ValueWrapper the value to which this cache maps the specified key, contained within a `ValueWrapper` which may also hold a cached `null` value. A straight `null` being returned means that the cache contains no mapping for this key. Annotations @Nullable See Also `get(Object, Class)`, `get(Object, Callable)`

public Cache.ValueWrapper get(Object key)

Return the value to which this cache maps the specified key.

Returns null if the cache contains no mapping for this key; otherwise, the cached value (which may be null itself) will be returned in a ValueWrapper.

Parameters

key:Object: the key whose associated value is to be returned

Returns:Cache.ValueWrapper

the value to which this cache maps the specified key, contained within a ValueWrapper which may also hold a cached null value. A straight null being returned means that the cache contains no mapping for this key.

Annotations

@Nullable

get back to summary

get	back to summary
public <T> T get(Object key, Class<T> type) Return the value to which this cache maps the specified key, generically specifying a type that return value will be cast to. Note This variant of `get` does not allow for differentiating between a cached `null` value and no cache entry found at all. Use the standard `get(Object)` variant for that purpose instead. Parameters key:Object the key whose associated value is to be returned type:Class<T> the required type of the returned value (may be `null` to bypass a type check; in case of a `null` value found in the cache, the specified type is irrelevant) Returns:T the value to which this cache maps the specified key (which may be `null` itself), or also `null` if the cache contains no mapping for this key Annotations @Nullable Exceptions IllegalStateException: if a cache entry has been found but failed to match the specified type Since 4.0 See Also `get(Object)`

public <T> T get(Object key, Class<T> type)

Return the value to which this cache maps the specified key, generically specifying a type that return value will be cast to.

Note

This variant of get does not allow for differentiating between a cached null value and no cache entry found at all. Use the standard get(Object) variant for that purpose instead.

Parameters

key:Object: the key whose associated value is to be returned
type:Class<T>: the required type of the returned value (may be null to bypass a type check; in case of a null value found in the cache, the specified type is irrelevant)

Returns:T

the value to which this cache maps the specified key (which may be null itself), or also null if the cache contains no mapping for this key

Annotations

@Nullable

Exceptions

IllegalStateException:: if a cache entry has been found but failed to match the specified type

Since

4.0

See Also

get(Object)

get back to summary

get	back to summary
public <T> T get(Object key, Callable<T> valueLoader) Return the value to which this cache maps the specified key, obtaining that value from `valueLoader` if necessary. This method provides a simple substitute for the conventional "if cached, return; otherwise create, cache and return" pattern. If possible, implementations should ensure that the loading operation is synchronized so that the specified `valueLoader` is only called once in case of concurrent access on the same key. If the `valueLoader` throws an exception, it is wrapped in a `ValueRetrievalException` Parameters key:Object the key whose associated value is to be returned Returns:T the value to which this cache maps the specified key Annotations @Nullable Exceptions ValueRetrievalException: if the `valueLoader` throws an exception Since 4.3 See Also `get(Object)`

public <T> T get(Object key, Callable<T> valueLoader)

Return the value to which this cache maps the specified key, obtaining that value from valueLoader if necessary. This method provides a simple substitute for the conventional "if cached, return; otherwise create, cache and return" pattern.

If possible, implementations should ensure that the loading operation is synchronized so that the specified valueLoader is only called once in case of concurrent access on the same key.

If the valueLoader throws an exception, it is wrapped in a ValueRetrievalException

Parameters

key:Object: the key whose associated value is to be returned

Returns:T

the value to which this cache maps the specified key

Annotations

@Nullable

Exceptions

ValueRetrievalException:: if the valueLoader throws an exception

Since

4.3

See Also

get(Object)

getName	back to summary
public String getName() Return the cache name.

getNativeCache	back to summary
public Object getNativeCache() Return the underlying native cache provider.

invalidate back to summary

invalidate	back to summary
public default boolean invalidate() Invalidate the cache through removing all mappings, expecting all entries to be immediately invisible for subsequent lookups. Returns:boolean `true` if the cache was known to have mappings before, `false` if it did not (or if prior presence of entries could not be determined) Since 5.2 See Also `clear()`

public default boolean invalidate()

Invalidate the cache through removing all mappings, expecting all entries to be immediately invisible for subsequent lookups.

Returns:boolean: true if the cache was known to have mappings before, false if it did not (or if prior presence of entries could not be determined)
Since: 5.2
See Also: clear()

put back to summary

put	back to summary
public void put(Object key, Object value) Associate the specified value with the specified key in this cache. If the cache previously contained a mapping for this key, the old value is replaced by the specified value. Actual registration may be performed in an asynchronous or deferred fashion, with subsequent lookups possibly not seeing the entry yet. This may for example be the case with transactional cache decorators. Use `putIfAbsent` for guaranteed immediate registration. If the cache is supposed to be compatible with `CompletableFuture` and reactive interactions, the put operation needs to be effectively non-blocking, with any backend write-through happening asynchronously. This goes along with a cache implemented and configured to support `retrieve(Object)` and `retrieve(Object, Supplier)`. Parameters key:Object the key with which the specified value is to be associated value:Object the value to be associated with the specified key See Also `putIfAbsent(Object, Object)`

public void put(Object key, Object value)

Associate the specified value with the specified key in this cache.

If the cache previously contained a mapping for this key, the old value is replaced by the specified value.

Actual registration may be performed in an asynchronous or deferred fashion, with subsequent lookups possibly not seeing the entry yet. This may for example be the case with transactional cache decorators. Use putIfAbsent for guaranteed immediate registration.

If the cache is supposed to be compatible with CompletableFuture and reactive interactions, the put operation needs to be effectively non-blocking, with any backend write-through happening asynchronously. This goes along with a cache implemented and configured to support retrieve(Object) and retrieve(Object, Supplier).

Parameters

key:Object: the key with which the specified value is to be associated
value:Object: the value to be associated with the specified key

See Also

putIfAbsent(Object, Object)

putIfAbsent back to summary

putIfAbsent	back to summary
public default Cache.ValueWrapper putIfAbsent(Object key, Object value) Atomically associate the specified value with the specified key in this cache if it is not set already. This is equivalent to: `ValueWrapper existingValue = cache.get(key); if (existingValue == null) { cache.put(key, value); } return existingValue;` except that the action is performed atomically. While all out-of-the-box `CacheManager` implementations are able to perform the put atomically, the operation may also be implemented in two steps, e.g. with a check for presence and a subsequent put, in a non-atomic way. Check the documentation of the native cache implementation that you are using for more details. The default implementation delegates to `get(Object)` and `put(Object, Object)` along the lines of the code snippet above. Parameters key:Object the key with which the specified value is to be associated value:Object the value to be associated with the specified key Returns:Cache.ValueWrapper the value to which this cache maps the specified key (which may be `null` itself), or also `null` if the cache did not contain any mapping for that key prior to this call. Returning `null` is therefore an indicator that the given `value` has been associated with the key. Annotations @Nullable Since 4.1 See Also `put(Object, Object)`

public default Cache.ValueWrapper putIfAbsent(Object key, Object value)

Atomically associate the specified value with the specified key in this cache if it is not set already.

This is equivalent to:


ValueWrapper existingValue = cache.get(key);
if (existingValue == null) {
    cache.put(key, value);
}
return existingValue;

except that the action is performed atomically. While all out-of-the-box CacheManager implementations are able to perform the put atomically, the operation may also be implemented in two steps, e.g. with a check for presence and a subsequent put, in a non-atomic way. Check the documentation of the native cache implementation that you are using for more details.

The default implementation delegates to get(Object) and put(Object, Object) along the lines of the code snippet above.

Parameters

key:Object: the key with which the specified value is to be associated
value:Object: the value to be associated with the specified key

Returns:Cache.ValueWrapper

the value to which this cache maps the specified key (which may be null itself), or also null if the cache did not contain any mapping for that key prior to this call. Returning null is therefore an indicator that the given value has been associated with the key.

Annotations

@Nullable

Since

4.1

See Also

put(Object, Object)

retrieve back to summary

retrieve	back to summary
public default CompletableFuture<?> retrieve(Object key) Return the value to which this cache maps the specified key, wrapped in a `CompletableFuture`. This operation must not block but is allowed to return a completed `CompletableFuture` if the corresponding value is immediately available. Can return `null` if the cache can immediately determine that it contains no mapping for this key (e.g. through an in-memory key map). Otherwise, the cached value will be returned in the `CompletableFuture`, with `null` indicating a late-determined cache miss. A nested `ValueWrapper` potentially indicates a nullable cached value; the cached value may also be represented as a plain element if null values are not supported. Calling code needs to be prepared to handle all those variants of the result returned by this method. Parameters key:Object the key whose associated value is to be returned Returns:CompletableFuture<?> the value to which this cache maps the specified key, contained within a `CompletableFuture` which may also be empty when a cache miss has been late-determined. A straight `null` being returned means that the cache immediately determined that it contains no mapping for this key. A `ValueWrapper` contained within the `CompletableFuture` indicates a cached value that is potentially `null`; this is sensible in a late-determined scenario where a regular CompletableFuture-contained `null` indicates a cache miss. However, a cache may also return a plain value if it does not support the actual caching of `null` values, avoiding the extra level of value wrapping. Spring's cache processing can deal with all such implementation strategies. Annotations @Nullable Since 6.1 See Also `retrieve(Object, Supplier)`

public default CompletableFuture<?> retrieve(Object key)

Return the value to which this cache maps the specified key, wrapped in a CompletableFuture. This operation must not block but is allowed to return a completed CompletableFuture if the corresponding value is immediately available.

Can return null if the cache can immediately determine that it contains no mapping for this key (e.g. through an in-memory key map). Otherwise, the cached value will be returned in the CompletableFuture, with null indicating a late-determined cache miss. A nested ValueWrapper potentially indicates a nullable cached value; the cached value may also be represented as a plain element if null values are not supported. Calling code needs to be prepared to handle all those variants of the result returned by this method.

Parameters

key:Object: the key whose associated value is to be returned

Returns:CompletableFuture<?>

the value to which this cache maps the specified key, contained within a CompletableFuture which may also be empty when a cache miss has been late-determined. A straight null being returned means that the cache immediately determined that it contains no mapping for this key. A ValueWrapper contained within the CompletableFuture indicates a cached value that is potentially null; this is sensible in a late-determined scenario where a regular CompletableFuture-contained null indicates a cache miss. However, a cache may also return a plain value if it does not support the actual caching of null values, avoiding the extra level of value wrapping. Spring's cache processing can deal with all such implementation strategies.

Annotations

@Nullable

Since

6.1

See Also

retrieve(Object, Supplier)

retrieve back to summary

retrieve	back to summary
public default <T> CompletableFuture<T> retrieve(Object key, Supplier<CompletableFuture<T>> valueLoader) Return the value to which this cache maps the specified key, obtaining that value from `valueLoader` if necessary. This method provides a simple substitute for the conventional "if cached, return; otherwise create, cache and return" pattern, based on `CompletableFuture`. This operation must not block. If possible, implementations should ensure that the loading operation is synchronized so that the specified `valueLoader` is only called once in case of concurrent access on the same key. Null values always indicate a user-level `null` value with this method. The provided `CompletableFuture` handle produces a value or raises an exception. If the `valueLoader` raises an exception, it will be propagated to the returned `CompletableFuture` handle. Parameters key:Object the key whose associated value is to be returned Returns:CompletableFuture<T> the value to which this cache maps the specified key, contained within a `CompletableFuture` which will never be `null`. The provided future is expected to produce a value or raise an exception. Since 6.1 See Also `retrieve(Object)`, `get(Object, Callable)`

public default <T> CompletableFuture<T> retrieve(Object key, Supplier<CompletableFuture<T>> valueLoader)

If possible, implementations should ensure that the loading operation is synchronized so that the specified valueLoader is only called once in case of concurrent access on the same key.

Null values always indicate a user-level null value with this method. The provided CompletableFuture handle produces a value or raises an exception. If the valueLoader raises an exception, it will be propagated to the returned CompletableFuture handle.

Parameters

key:Object: the key whose associated value is to be returned

Returns:CompletableFuture<T>

the value to which this cache maps the specified key, contained within a CompletableFuture which will never be null. The provided future is expected to produce a value or raise an exception.

Since

6.1

public Interface Cache

Nested and Inner Type Summary

Method Summary

Method Detail

public Class Cache.ValueRetrievalException

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

public Interface Cache.ValueWrapper

Method Summary

Method Detail