com.oracle.graal.pointsto.util

Class LightImmutableCollection

java.lang.Object

com.oracle.graal.pointsto.util.LightImmutableCollection

public final class LightImmutableCollection
extends Object

Implements a memory efficient immutable collection. The memory efficiency comes from the fact that there is no wrapping overhead when the collection contains zero or one element. When the collection contains a single entry then the value is stored as is. When the collection is empty then the field is null. The value is not referenced by objects of this class but all operations use a AtomicReferenceFieldUpdater to a storage location of type Object. This location is then populated with three possible values:

1. No entries: the location is set to null
2. One entry: the entry is stored directly in this location as is
3. Multiple entries: the location points to a Object array storing the entries

This collection cannot store types which are assignable from Object[].

Method Summary

Modifier and Type	Method and Description
static <T,U> boolean	allMatch(U holder, AtomicReferenceFieldUpdater<U,Object> updater, Predicate<? super T> predicate)
static <T,U> void	forEach(U holder, AtomicReferenceFieldUpdater<U,Object> updater, Consumer<? super T> action)
static <T,U> void	initializeNonEmpty(U holder, AtomicReferenceFieldUpdater<U,Object> updater, Collection<T> value) Initializes collection.
static <T,U> void	initializeNonEmpty(U holder, AtomicReferenceFieldUpdater<U,Object> updater, T element) Initializes collection.
static <T> boolean	isEmpty(T holder, AtomicReferenceFieldUpdater<T,Object> updater)
static <U> int	size(U holder, AtomicReferenceFieldUpdater<U,Object> updater)
static <T,U> Collection<T>	toCollection(U holder, AtomicReferenceFieldUpdater<U,Object> updater)
static <T,U> T	toSingleElement(U holder, AtomicReferenceFieldUpdater<U,Object> updater) If the list contains only one element, then returns the element.

Methods inherited from class java.lang.Object

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

Method Detail

size

public static <U> int size(U holder,
                           AtomicReferenceFieldUpdater<U,Object> updater)

isEmpty

public static <T> boolean isEmpty(T holder,
                                  AtomicReferenceFieldUpdater<T,Object> updater)

forEach

public static <T,U> void forEach(U holder,
                                 AtomicReferenceFieldUpdater<U,Object> updater,
                                 Consumer<? super T> action)

allMatch

public static <T,U> boolean allMatch(U holder,
                                     AtomicReferenceFieldUpdater<U,Object> updater,
                                     Predicate<? super T> predicate)

toSingleElement

public static <T,U> T toSingleElement(U holder,
                                      AtomicReferenceFieldUpdater<U,Object> updater)

If the list contains only one element, then returns the element. Otherwise, returns null.

toCollection

public static <T,U> Collection<T> toCollection(U holder,
                                               AtomicReferenceFieldUpdater<U,Object> updater)

initializeNonEmpty

public static <T,U> void initializeNonEmpty(U holder,
                                            AtomicReferenceFieldUpdater<U,Object> updater,
                                            T element)

Initializes collection. Note this is operation can race if called multiple times concurrently.

initializeNonEmpty

public static <T,U> void initializeNonEmpty(U holder,
                                            AtomicReferenceFieldUpdater<U,Object> updater,
                                            Collection<T> value)

Initializes collection. Note this is operation can race if called multiple times concurrently.