com.nytimes.android.external.cache

Class CacheLoader<K,V>

java.lang.Object

com.nytimes.android.external.cache.CacheLoader<K,V>

public abstract class CacheLoader<K,V>
extends java.lang.Object

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CacheLoader.InvalidCacheLoadException Thrown to indicate that an invalid response was returned from a call to CacheLoader.
static class	CacheLoader.UnsupportedLoadingOperationException Exception thrown by loadAll() to indicate that it is not supported.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	CacheLoader() Constructor for use by subclasses.

Method Summary

Modifier and Type	Method and Description
static <K,V> CacheLoader<K,V>	from(Function<K,V> function) Returns a cache loader based on an existing function instance.
static <V> CacheLoader<java.lang.Object,V>	from(Supplier<V> supplier) Returns a cache loader based on an existing supplier instance.
abstract V	load(K key) Computes or retrieves the value corresponding to key.
java.util.Map<K,V>	loadAll(java.lang.Iterable<? extends K> keys)
ListenableFuture<V>	reload(K key, V oldValue)

Methods inherited from class java.lang.Object

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

Constructor Detail

CacheLoader

protected CacheLoader()

Constructor for use by subclasses.

Method Detail

load

@Nullable
public abstract V load(K key)
                          throws java.lang.Exception

Computes or retrieves the value corresponding to key.

Parameters:

key - the non-null key whose value should be loaded

Returns:

the value associated with key; must not be null

Throws:

java.lang.Exception - if unable to load the result

java.lang.InterruptedException - if this method is interrupted. InterruptedException is treated like any other Exception in all respects except that, when it is caught, the thread's interrupt status is set

reload

@Nullable
public ListenableFuture<V> reload(@Nonnull
                                            K key,
                                            @Nonnull
                                            V oldValue)
                                     throws java.lang.Exception

Throws:

java.lang.Exception

loadAll

@Nonnull
public java.util.Map<K,V> loadAll(java.lang.Iterable<? extends K> keys)
                                    throws java.lang.Exception

Throws:

java.lang.Exception

from

@Nonnull
public static <K,V> CacheLoader<K,V> from(@Nonnull
                                                   Function<K,V> function)

Returns a cache loader based on an existing function instance. Note that there's no need to create a new function just to pass it in here; just subclass CacheLoader and implement load instead.

Parameters:

function - the function to be used for loading values; must never return null

Returns:

a cache loader that loads values by passing each key to function

from

@Nonnull
public static <V> CacheLoader<java.lang.Object,V> from(@Nonnull
                                                                Supplier<V> supplier)

Returns a cache loader based on an existing supplier instance. Note that there's no need to create a new supplier just to pass it in here; just subclass CacheLoader and implement load instead.

Parameters:

supplier - the supplier to be used for loading values; must never return null

Returns:

a cache loader that loads values by calling Supplier.get(), irrespective of the key