Apache Commons Collections 4.4 · org.apache.commons.collections4.MultiSetUtils

Modifier and Type	Field and Description
public static final MultiSet<E>	EMPTY_MULTISET An empty unmodifiable multiset.

Access	Constructor and Description
private	MultiSetUtils() Instantiation of MultiSetUtils is not intended or required.

Method Summary

Modifier and Type	Method and Description
public static < the element type E> MultiSet<E>	Returns: an empty MultiSet emptyMultiSet() Get an empty `MultiSet`.
public static < the element type E> MultiSet<E>	Returns: a predicated multiset backed by the given multiset predicatedMultiSet(final MultiSet<E> the multiset to predicate, must not be null multiset, final Predicate<? super E> the predicate for the multiset, must not be null predicate) Returns a predicated (validating) multiset backed by the given multiset.
public static < the element type E> MultiSet<E>	Returns: a synchronized multiset backed by that multiset synchronizedMultiSet(final MultiSet<E> the multiset to synchronize, must not be null multiset) Returns a synchronized (thread-safe) multiset backed by the given multiset.
public static < the element type E> MultiSet<E>	Returns: an unmodifiable view of that multiset unmodifiableMultiSet(final MultiSet<? extends E> the multiset whose unmodifiable view is to be returned, must not be null multiset) Returns an unmodifiable view of the given multiset.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

EMPTY_MULTISET	back to summary
public static final MultiSet<E> EMPTY_MULTISET An empty unmodifiable multiset. Annotations @SuppressWarnings:rawtypes

MultiSetUtils	back to summary
private MultiSetUtils() Instantiation of MultiSetUtils is not intended or required.

Method Detail

emptyMultiSet back to summary

emptyMultiSet	back to summary
public static <E> MultiSet<E> emptyMultiSet() Get an empty `MultiSet`. Parameters <E> the element type Returns:MultiSet<E> an empty MultiSet Annotations @SuppressWarnings:unchecked

public static <E> MultiSet<E> emptyMultiSet()

Get an empty MultiSet.

Parameters

<E>: the element type

Returns:MultiSet<E>

an empty MultiSet

Annotations

@SuppressWarnings:unchecked

predicatedMultiSet	back to summary
public static <E> MultiSet<E> predicatedMultiSet(final MultiSet<E> multiset, final Predicate<? super E> predicate) Returns a predicated (validating) multiset backed by the given multiset. Only objects that pass the test in the given predicate can be added to the multiset. Trying to add an invalid object results in an IllegalArgumentException. It is important not to use the original multiset after invoking this method, as it is a backdoor for adding invalid objects. Parameters <E> the element type multiset:MultiSet<E> the multiset to predicate, must not be null predicate:Predicate<? super E> the predicate for the multiset, must not be null Returns:MultiSet<E> a predicated multiset backed by the given multiset Exceptions NullPointerException: if the MultiSet or Predicate is null

predicatedMultiSet

back to summary

public static <E> MultiSet<E> predicatedMultiSet(final MultiSet<E> multiset, final Predicate<? super E> predicate)

Returns a predicated (validating) multiset backed by the given multiset.

Only objects that pass the test in the given predicate can be added to the multiset. Trying to add an invalid object results in an IllegalArgumentException. It is important not to use the original multiset after invoking this method, as it is a backdoor for adding invalid objects.

Parameters

<E>: the element type
multiset:MultiSet<E>: the multiset to predicate, must not be null
predicate:Predicate<? super E>: the predicate for the multiset, must not be null

Returns:MultiSet<E>

a predicated multiset backed by the given multiset

Exceptions

NullPointerException:: if the MultiSet or Predicate is null

synchronizedMultiSet	back to summary
public static <E> MultiSet<E> synchronizedMultiSet(final MultiSet<E> multiset) Returns a synchronized (thread-safe) multiset backed by the given multiset. In order to guarantee serial access, it is critical that all access to the backing multiset is accomplished through the returned multiset. It is imperative that the user manually synchronize on the returned multiset when iterating over it: MultiSet multiset = MultiSetUtils.synchronizedMultiSet(new HashMultiSet()); ... synchronized(multiset) { Iterator i = multiset.iterator(); // Must be in synchronized block while (i.hasNext()) foo(i.next()); } } Failure to follow this advice may result in non-deterministic behavior. Parameters <E> the element type multiset:MultiSet<E> the multiset to synchronize, must not be null Returns:MultiSet<E> a synchronized multiset backed by that multiset Exceptions NullPointerException: if the MultiSet is null

synchronizedMultiSet

back to summary

public static <E> MultiSet<E> synchronizedMultiSet(final MultiSet<E> multiset)

Returns a synchronized (thread-safe) multiset backed by the given multiset. In order to guarantee serial access, it is critical that all access to the backing multiset is accomplished through the returned multiset.

It is imperative that the user manually synchronize on the returned multiset when iterating over it:

MultiSet multiset = MultiSetUtils.synchronizedMultiSet(new HashMultiSet());
...
synchronized(multiset) {
    Iterator i = multiset.iterator(); // Must be in synchronized block
    while (i.hasNext())
        foo(i.next());
    }
}

Failure to follow this advice may result in non-deterministic behavior.

Parameters

<E>: the element type
multiset:MultiSet<E>: the multiset to synchronize, must not be null

Returns:MultiSet<E>

a synchronized multiset backed by that multiset

Exceptions

NullPointerException:: if the MultiSet is null

unmodifiableMultiSet back to summary

unmodifiableMultiSet	back to summary
public static <E> MultiSet<E> unmodifiableMultiSet(final MultiSet<? extends E> multiset) Returns an unmodifiable view of the given multiset. Any modification attempts to the returned multiset will raise an `UnsupportedOperationException`. Parameters <E> the element type multiset:MultiSet<? extends E> the multiset whose unmodifiable view is to be returned, must not be null Returns:MultiSet<E> an unmodifiable view of that multiset Exceptions NullPointerException: if the MultiSet is null

public static <E> MultiSet<E> unmodifiableMultiSet(final MultiSet<? extends E> multiset)

Returns an unmodifiable view of the given multiset. Any modification attempts to the returned multiset will raise an UnsupportedOperationException.

Parameters

<E>: the element type
multiset:MultiSet<? extends E>: the multiset whose unmodifiable view is to be returned, must not be null

Returns:MultiSet<E>

an unmodifiable view of that multiset

Exceptions

NullPointerException:: if the MultiSet is null

public Class MultiSetUtils

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Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail