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

This class provides a skeletal implementation of the Cache interface to minimize the effort required to implement this interface.

To implement a cache, the programmer needs only to extend this class and provide an implementation for the get(Object) and getIfPresent methods. getUnchecked, get(Object, Callable), and getAll are implemented in terms of get; getAllPresent is implemented in terms of getIfPresent; putAll is implemented in terms of put, invalidateAll(Iterable) is implemented in terms of invalidate. The method cleanUp is a no-op. All other methods throw an UnsupportedOperationException.

Access	Constructor and Description
protected	AbstractLoadingCache() Constructor for use by subclasses.

Method Summary

Modifier and Type	Method and Description
public final V	apply(K the function argument key) Implements com.google.common.cache.LoadingCache.apply. Applies this function to the given argument.
public ImmutableMap<K, V>	getAll(Iterable<? extends K> keys) Implements com.google.common.cache.LoadingCache.getAll. Returns a map of the values associated with `keys`, creating or retrieving those values if necessary.
public V	getUnchecked(K key) Implements com.google.common.cache.LoadingCache.getUnchecked. Returns the value associated with `key` in this cache, first loading that value if necessary.
public void	refresh(K key) Implements com.google.common.cache.LoadingCache.refresh. Loads a new value for `key`, possibly asynchronously.

Inherited from com.google.common.cache.AbstractCache:: asMap cleanUp get getAllPresent invalidate invalidateAll invalidateAll put putAll size stats

Constructor Detail

AbstractLoadingCache	back to summary
protected AbstractLoadingCache() Constructor for use by subclasses.

Method Detail

apply	back to summary
public final V apply(K key) Implements com.google.common.cache.LoadingCache.apply. Doc from java.util.function.Function.apply. Applies this function to the given argument. Parameters key:K the function argument Returns:V the function result Annotations @Override

apply

back to summary

public final V apply(K key)

Implements com.google.common.cache.LoadingCache.apply.

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

Applies this function to the given argument.

Parameters

key:K: the function argument

Returns:V

the function result

Annotations

@Override

getAll back to summary

getAll	back to summary
public ImmutableMap<K, V> getAll(Iterable<? extends K> keys) throws ExecutionException Implements com.google.common.cache.LoadingCache.getAll. Doc from com.google.common.cache.LoadingCache.getAll. 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 @Override Exceptions ExecutionException: if a checked exception was thrown while loading the value. (`ExecutionException` is thrown even if computation was interrupted by an `InterruptedException`.)

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

Implements com.google.common.cache.LoadingCache.getAll.

Doc from com.google.common.cache.LoadingCache.getAll.

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

@Override

Exceptions

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

getUnchecked back to summary

getUnchecked	back to summary
public V getUnchecked(K key) Implements com.google.common.cache.LoadingCache.getUnchecked. Doc from com.google.common.cache.LoadingCache.getUnchecked. 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 @Override

public V getUnchecked(K key)

Implements com.google.common.cache.LoadingCache.getUnchecked.

Doc from com.google.common.cache.LoadingCache.getUnchecked.

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
@Override

refresh back to summary

refresh	back to summary
public void refresh(K key) Implements com.google.common.cache.LoadingCache.refresh. Doc from com.google.common.cache.LoadingCache.refresh. 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. Annotations @Override

public void refresh(K key)

Implements com.google.common.cache.LoadingCache.refresh.

Doc from com.google.common.cache.LoadingCache.refresh.

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.

Annotations

@Override

public abstract Class AbstractLoadingCache<K, V>

Constructor Summary

Method Summary

Constructor Detail

Method Detail