org.apache.commons.collections4.collection

Class PredicatedCollection<E>

java.lang.Object

org.apache.commons.collections4.collection.AbstractCollectionDecorator<E>

org.apache.commons.collections4.collection.PredicatedCollection<E>

Type Parameters:

E - the type of the elements in the collection

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable<E>, java.util.Collection<E>

Direct Known Subclasses:

PredicatedBag, PredicatedList, PredicatedMultiSet, PredicatedQueue, PredicatedSet

public class PredicatedCollection<E>
extends AbstractCollectionDecorator<E>

Decorates another Collection to validate that additions match a specified predicate.

This collection exists to provide validation for the decorated collection. It is normally created to decorate an empty collection. If an object cannot be added to the collection, an IllegalArgumentException is thrown.

One usage would be to ensure that no null entries are added to the collection:

 Collection coll = PredicatedCollection.predicatedCollection(new ArrayList(), NotNullPredicate.INSTANCE);
 

This class is Serializable from Commons Collections 3.1.

Since:

3.0

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PredicatedCollection.Builder<E> Builder for creating predicated collections.

Method Summary

Modifier and Type	Method and Description
boolean	add(E object) Override to validate the object being added to ensure it matches the predicate.
boolean	addAll(java.util.Collection<? extends E> coll) Override to validate the objects being added to ensure they match the predicate.
static <E> PredicatedCollection.Builder<E>	builder(Predicate<? super E> predicate) Returns a Builder with the given predicate.
static <E> PredicatedCollection.Builder<E>	notNullBuilder() Returns a Builder with a NotNullPredicate.
static <T> PredicatedCollection<T>	predicatedCollection(java.util.Collection<T> coll, Predicate<? super T> predicate) Factory method to create a predicated (validating) collection.

Methods inherited from class org.apache.commons.collections4.collection.AbstractCollectionDecorator

clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toArray, toString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

equals, hashCode, parallelStream, removeIf, spliterator, stream

Methods inherited from interface java.lang.Iterable

forEach

Method Detail

builder

public static <E> PredicatedCollection.Builder<E> builder(Predicate<? super E> predicate)

Returns a Builder with the given predicate.

Type Parameters:

E - the element type

Parameters:

predicate - the predicate to use

Returns:

a new Builder for predicated collections

Since:

4.1

notNullBuilder

public static <E> PredicatedCollection.Builder<E> notNullBuilder()

Returns a Builder with a NotNullPredicate.

Type Parameters:

E - the element type

Returns:

a new Builder for predicated collections that ignores null values.

Since:

4.1

predicatedCollection

public static <T> PredicatedCollection<T> predicatedCollection(java.util.Collection<T> coll,
                                                               Predicate<? super T> predicate)

Factory method to create a predicated (validating) collection.

If there are any elements already in the collection being decorated, they are validated.

Type Parameters:

T - the type of the elements in the collection

Parameters:

coll - the collection to decorate, must not be null

predicate - the predicate to use for validation, must not be null

Returns:

a new predicated collection

Throws:

java.lang.NullPointerException - if collection or predicate is null

java.lang.IllegalArgumentException - if the collection contains invalid elements

Since:

4.0

add

public boolean add(E object)

Override to validate the object being added to ensure it matches the predicate.

Specified by:

add in interface java.util.Collection<E>

Overrides:

add in class AbstractCollectionDecorator<E>

Parameters:

object - the object being added

Returns:

the result of adding to the underlying collection

Throws:

java.lang.IllegalArgumentException - if the add is invalid

addAll

public boolean addAll(java.util.Collection<? extends E> coll)

Override to validate the objects being added to ensure they match the predicate. If any one fails, no update is made to the underlying collection.

Specified by:

addAll in interface java.util.Collection<E>

Overrides:

addAll in class AbstractCollectionDecorator<E>

Parameters:

coll - the collection being added

Returns:

the result of adding to the underlying collection

Throws:

java.lang.IllegalArgumentException - if the add is invalid