Guava: Google Core Libraries for Java 32.1.2-jre · com.google.common.cache.LoadingCache

Modifier and Type	Method and Description
public V	apply(K the function argument key) Redeclares com.google.common.base.Function.apply. Deprecated Provided to satisfy the `Function` interface; use `get` or `getUnchecked` instead. Applies this function to the given argument.
public ConcurrentMap<K, V>	asMap() Redeclares com.google.common.cache.Cache.asMap. Returns a view of the entries stored in this cache as a thread-safe map.
public V	get(K key) Returns the value associated with `key` in this cache, first loading that value if necessary.
public ImmutableMap<K, V>	getAll(Iterable<? extends K> keys) Returns a map of the values associated with `keys`, creating or retrieving those values if necessary.
public V	getUnchecked(K key) Returns the value associated with `key` in this cache, first loading that value if necessary.
public void	refresh(K key) Loads a new value for `key`, possibly asynchronously.

Method Detail

apply back to summary

apply	back to summary
public V apply(K key) Redeclares com.google.common.base.Function.apply. Doc from java.util.function.Function.apply. Deprecated Provided to satisfy the `Function` interface; use `get` or `getUnchecked` instead. Applies this function to the given argument. Parameters key:K the function argument Returns:V the function result Annotations @Deprecated @Override Exceptions UncheckedExecutionException: if an exception was thrown while loading the value. (As described in the documentation for `getUnchecked`, `LoadingCache` should be used as a `Function` only with cache loaders that throw only unchecked exceptions.)

public V apply(K key)

Redeclares com.google.common.base.Function.apply.

Doc from java.util.function.Function.apply.

Deprecated

Provided to satisfy the Function interface; use get or getUnchecked instead.

Applies this function to the given argument.

Parameters

key:K: the function argument

Returns:V

the function result

Annotations

@Deprecated
@Override

Exceptions

UncheckedExecutionException:: if an exception was thrown while loading the value. (As described in the documentation for getUnchecked, LoadingCache should be used as a Function only with cache loaders that throw only unchecked exceptions.)

asMap	back to summary
public ConcurrentMap<K, V> asMap() Redeclares com.google.common.cache.Cache.asMap. Doc from com.google.common.cache.Cache.asMap. Returns a view of the entries stored in this cache as a thread-safe map. Modifications made to the map directly affect the cache. Iterators from the returned map are at least weakly consistent: they are safe for concurrent use, but if the cache is modified (including by eviction) after the iterator is created, it is undefined which of the changes (if any) will be reflected in that iterator. Note that although the view is modifiable, no method on the returned map will ever cause entries to be automatically loaded. Annotations @Override

asMap

back to summary

public ConcurrentMap<K, V> asMap()

Redeclares com.google.common.cache.Cache.asMap.

Doc from com.google.common.cache.Cache.asMap.

Returns a view of the entries stored in this cache as a thread-safe map. Modifications made to the map directly affect the cache.

Iterators from the returned map are at least weakly consistent: they are safe for concurrent use, but if the cache is modified (including by eviction) after the iterator is created, it is undefined which of the changes (if any) will be reflected in that iterator.

Note that although the view is modifiable, no method on the returned map will ever cause entries to be automatically loaded.

Annotations

@Override

get back to summary

get	back to summary
public V get(K key) throws ExecutionException Returns the value associated with `key` in this cache, first loading that value if necessary. No observable state associated with this cache is modified until loading completes. If another call to `get` or `getUnchecked` is currently loading the value for `key`, simply waits for that thread to finish and returns its loaded value. Note that multiple threads can concurrently load values for distinct keys. Caches loaded by a `CacheLoader` will call `CacheLoader#load` to load new values into the cache. Newly loaded values are added to the cache using `Cache.asMap().putIfAbsent` after loading has completed; if another value was associated with `key` while the new value was loading then a removal notification will be sent for the new value. If the cache loader associated with this cache is known not to throw checked exceptions, then prefer `getUnchecked` over this method. Annotations @CanIgnoreReturnValue Exceptions ExecutionException: if a checked exception was thrown while loading the value. (`ExecutionException` is thrown even if computation was interrupted by an `InterruptedException`.) UncheckedExecutionException: if an unchecked exception was thrown while loading the value ExecutionError: if an error was thrown while loading the value

public V get(K key) throws ExecutionException

Returns the value associated with key in this cache, first loading that value if necessary. No observable state associated with this cache is modified until loading completes.

If another call to get or getUnchecked is currently loading the value for key, simply waits for that thread to finish and returns its loaded value. Note that multiple threads can concurrently load values for distinct keys.

Caches loaded by a CacheLoader will call CacheLoader#load to load new values into the cache. Newly loaded values are added to the cache using Cache.asMap().putIfAbsent after loading has completed; if another value was associated with key while the new value was loading then a removal notification will be sent for the new value.

If the cache loader associated with this cache is known not to throw checked exceptions, then prefer getUnchecked over this method.

Annotations

@CanIgnoreReturnValue

Exceptions

ExecutionException:: if a checked exception was thrown while loading the value. (ExecutionException is thrown even if computation was interrupted by an InterruptedException.)
UncheckedExecutionException:: if an unchecked exception was thrown while loading the value
ExecutionError:: if an error was thrown while loading the value

getAll back to summary

getAll	back to summary
public ImmutableMap<K, V> getAll(Iterable<? extends K> keys) throws ExecutionException Returns a map of the values associated with `keys`, creating or retrieving those values if necessary. The returned map contains entries that were already cached, combined with newly loaded entries; it will never contain null keys or values. Caches loaded by a `CacheLoader` will issue a single request to `CacheLoader#loadAll` for all keys which are not already present in the cache. All entries returned by `CacheLoader#loadAll` will be stored in the cache, over-writing any previously cached values. This method will throw an exception if `CacheLoader#loadAll` returns `null`, returns a map containing null keys or values, or fails to return an entry for each requested key. Note that duplicate elements in `keys`, as determined by `Object#equals`, will be ignored. Annotations @CanIgnoreReturnValue Exceptions ExecutionException: if a checked exception was thrown while loading the value. (`ExecutionException` is thrown even if computation was interrupted by an `InterruptedException`.) UncheckedExecutionException: if an unchecked exception was thrown while loading the values ExecutionError: if an error was thrown while loading the values Since 11.0

public ImmutableMap<K, V> getAll(Iterable<? extends K> keys) throws ExecutionException

Returns a map of the values associated with keys, creating or retrieving those values if necessary. The returned map contains entries that were already cached, combined with newly loaded entries; it will never contain null keys or values.

Caches loaded by a CacheLoader will issue a single request to CacheLoader#loadAll for all keys which are not already present in the cache. All entries returned by CacheLoader#loadAll will be stored in the cache, over-writing any previously cached values. This method will throw an exception if CacheLoader#loadAll returns null, returns a map containing null keys or values, or fails to return an entry for each requested key.

Note that duplicate elements in keys, as determined by Object#equals, will be ignored.

Annotations

@CanIgnoreReturnValue

Exceptions

ExecutionException:: if a checked exception was thrown while loading the value. (ExecutionException is thrown even if computation was interrupted by an InterruptedException.)
UncheckedExecutionException:: if an unchecked exception was thrown while loading the values
ExecutionError:: if an error was thrown while loading the values

Since

11.0

getUnchecked back to summary

getUnchecked	back to summary
public V getUnchecked(K key) Returns the value associated with `key` in this cache, first loading that value if necessary. No observable state associated with this cache is modified until loading completes. Unlike `get`, this method does not throw a checked exception, and thus should only be used in situations where checked exceptions are not thrown by the cache loader. If another call to `get` or `getUnchecked` is currently loading the value for `key`, simply waits for that thread to finish and returns its loaded value. Note that multiple threads can concurrently load values for distinct keys. Caches loaded by a `CacheLoader` will call `CacheLoader#load` to load new values into the cache. Newly loaded values are added to the cache using `Cache.asMap().putIfAbsent` after loading has completed; if another value was associated with `key` while the new value was loading then a removal notification will be sent for the new value. Warning this method silently converts checked exceptions to unchecked exceptions, and should not be used with cache loaders which throw checked exceptions. In such cases use `get` instead. Annotations @CanIgnoreReturnValue Exceptions UncheckedExecutionException: if an exception was thrown while loading the value. (As explained in the last paragraph above, this should be an unchecked exception only.) ExecutionError: if an error was thrown while loading the value

public V getUnchecked(K key)

Returns the value associated with key in this cache, first loading that value if necessary. No observable state associated with this cache is modified until loading completes. Unlike get, this method does not throw a checked exception, and thus should only be used in situations where checked exceptions are not thrown by the cache loader.

Warning

this method silently converts checked exceptions to unchecked exceptions, and should not be used with cache loaders which throw checked exceptions. In such cases use get instead.

Annotations

@CanIgnoreReturnValue

Exceptions

UncheckedExecutionException:: if an exception was thrown while loading the value. (As explained in the last paragraph above, this should be an unchecked exception only.)
ExecutionError:: if an error was thrown while loading the value

refresh back to summary

refresh	back to summary
public void refresh(K key) Loads a new value for `key`, possibly asynchronously. While the new value is loading the previous value (if any) will continue to be returned by `get(key)` unless it is evicted. If the new value is loaded successfully it will replace the previous value in the cache; if an exception is thrown while refreshing the previous value will remain, and the exception will be logged (using `java.util.logging.Logger`) and swallowed. Caches loaded by a `CacheLoader` will call `CacheLoader#reload` if the cache currently contains a value for `key`, and `CacheLoader#load` otherwise. Loading is asynchronous only if `CacheLoader#reload` was overridden with an asynchronous implementation. Returns without doing anything if another thread is currently loading the value for `key`. If the cache loader associated with this cache performs refresh asynchronously then this method may return before refresh completes. Since 11.0

public void refresh(K key)

Loads a new value for key, possibly asynchronously. While the new value is loading the previous value (if any) will continue to be returned by get(key) unless it is evicted. If the new value is loaded successfully it will replace the previous value in the cache; if an exception is thrown while refreshing the previous value will remain, and the exception will be logged (using java.util.logging.Logger) and swallowed.

Caches loaded by a CacheLoader will call CacheLoader#reload if the cache currently contains a value for key, and CacheLoader#load otherwise. Loading is asynchronous only if CacheLoader#reload was overridden with an asynchronous implementation.

Returns without doing anything if another thread is currently loading the value for key. If the cache loader associated with this cache performs refresh asynchronously then this method may return before refresh completes.

Since: 11.0

public Interface LoadingCache<K, V>

Method Summary

Method Detail