org.apache.beam.fn.harness

Class Caches

java.lang.Object

org.apache.beam.fn.harness.Caches

public final class Caches
extends java.lang.Object

Utility methods used to instantiate and operate over cache instances.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Caches.ClearableCache<K,V> A cache that tracks keys that have been inserted into the cache and supports clearing them.

Constructor Summary

Constructors

Constructor and Description
Caches()

Method Summary

Modifier and Type	Method and Description
static <K,V> Cache<K,V>	eternal() A cache that never evicts any values.
static <K,V> Cache<K,V>	fromOptions(org.apache.beam.sdk.options.PipelineOptions options) Uses the specified PipelineOptions to configure and return a cache instance based upon parameters within SdkHarnessOptions.
static <K,V> Cache<K,V>	noop() A cache that never stores any values.
static <K,V> Cache<K,V>	subCache(Cache<?,?> cache, java.lang.Object keyPrefix, java.lang.Object... additionalKeyPrefix) Returns a view of a cache that operates on keys with a specified key prefix.
static long	weigh(java.lang.Object o)

Methods inherited from class java.lang.Object

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

Constructor Detail

Caches

public Caches()

Method Detail

weigh

public static long weigh(java.lang.Object o)

noop

public static <K,V> Cache<K,V> noop()

A cache that never stores any values.

eternal

public static <K,V> Cache<K,V> eternal()

A cache that never evicts any values.

fromOptions

public static <K,V> Cache<K,V> fromOptions(org.apache.beam.sdk.options.PipelineOptions options)

Uses the specified PipelineOptions to configure and return a cache instance based upon parameters within SdkHarnessOptions.

subCache

public static <K,V> Cache<K,V> subCache(Cache<?,?> cache,
                                        java.lang.Object keyPrefix,
                                        java.lang.Object... additionalKeyPrefix)

Returns a view of a cache that operates on keys with a specified key prefix.

All lookups, insertions, and removals into the parent Cache will be prefixed by the specified prefixes.