Package com.globalmentor.collections
Class Collections
- java.lang.Object
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- com.globalmentor.collections.Collections
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public class Collections extends java.lang.Object
Various utilities to be used with collections.- Author:
- Garret Wilson
- See Also:
Collection
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Constructor Summary
Constructors Constructor Description Collections()
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static boolean
addAll(java.util.Collection<? super java.lang.String> stringCollection, java.util.Collection<?> collection)
Adds the string representation of the elements specified by the collection to the specified string collection.static <T> boolean
addAll(java.util.Collection<T> collection, java.lang.Iterable<? extends T> iterable)
Adds all of the elements specified by the given iterable to the specified collection.static <T> boolean
addAll(java.util.Collection<T> collection, java.util.Iterator<? extends T> iterator)
Adds all of the elements specified by the given iterator to the specified collection.static <T> boolean
containsInstance(java.util.Collection<T> collection, java.lang.Class<? extends T> objectClass)
Determines if the given collection contains an object that is an instance of the given class.static <E> java.util.HashSet<E>
createHashSet(E... elements)
Creates a hash set of the given generic type and initializes it with the given elements.static <T> T
get(java.lang.Iterable<T> iterable)
Retrieves the first iterated object, if any, from the iterable.static <T> T
get(java.util.Collection<T> collection)
Retrieves the first iterated object, if any, from the collection.static <T> boolean
isEmpty(java.lang.Iterable<T> iterable)
Determines whether the iterable is empty.static <T> boolean
removeAll(java.util.Collection<T> collection, java.lang.Iterable<? extends T> iterable)
Removes all of the elements specified by the given iterable from the specified collection.static <T> boolean
removeAll(java.util.Collection<T> collection, java.util.Iterator<? extends T> iterator)
Removes all of the elements specified by the given iterator from the specified collection.static <T> boolean
set(java.util.Collection<T> collection, java.util.Collection<? extends T> newCollection)
Sets the contents of the collection to the contents of the other given collection.static <T> boolean
set(java.util.Collection<T> collection, T... newElements)
Sets the contents of the collection to the contents of the other given collection.static <T> java.util.Collection<T>
toCollection(java.lang.Iterable<T> iterable)
Converts an iterable to a collection.static <T> java.lang.String
toString(java.util.Collection<T> collection)
Converts a collection to a string by concatenating the string values of each member of the collection, separated by a comma.static <T> java.lang.String
toString(java.util.Collection<T> collection, char delimiter)
Converts a collection to a string by concatenating the string values of each member of the collection, separated by the given delimiter character.static <T> java.lang.String
toString(java.util.Collection<T> collection, java.lang.String delimiter)
Converts a collection to a string by concatenating the string values of each member of the collection, separated by the given delimiter.
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Method Detail
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addAll
public static boolean addAll(java.util.Collection<? super java.lang.String> stringCollection, java.util.Collection<?> collection)
Adds the string representation of the elements specified by the collection to the specified string collection.- Parameters:
stringCollection
- The collection to which objects will be added.collection
- The source of the added strings.- Returns:
true
if the collection changed as a result of the call.
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addAll
public static <T> boolean addAll(java.util.Collection<T> collection, java.lang.Iterable<? extends T> iterable)
Adds all of the elements specified by the given iterable to the specified collection.- Type Parameters:
T
- The type of the elements contained on the collection.- Parameters:
collection
- The collection to which objects will be added.iterable
- The source of the added objects.- Returns:
true
if the collection changed as a result of the call.
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addAll
public static <T> boolean addAll(java.util.Collection<T> collection, java.util.Iterator<? extends T> iterator)
Adds all of the elements specified by the given iterator to the specified collection.- Type Parameters:
T
- The type of the elements contained on the collection.- Parameters:
collection
- The collection to which objects will be added.iterator
- The source of the added objects.- Returns:
true
if the collection changed as a result of the call.
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removeAll
public static <T> boolean removeAll(java.util.Collection<T> collection, java.lang.Iterable<? extends T> iterable)
Removes all of the elements specified by the given iterable from the specified collection.- Type Parameters:
T
- The type of the elements contained on the collection.- Parameters:
collection
- The collection from which objects will be removed.iterable
- The source of the removed objects.- Returns:
true
if the collection changed as a result of the call.
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removeAll
public static <T> boolean removeAll(java.util.Collection<T> collection, java.util.Iterator<? extends T> iterator)
Removes all of the elements specified by the given iterator from the specified collection.- Type Parameters:
T
- The type of the elements contained on the collection.- Parameters:
collection
- The collection from which objects will be removed.iterator
- The source of the removed objects.- Returns:
true
if the collection changed as a result of the call.
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containsInstance
public static <T> boolean containsInstance(java.util.Collection<T> collection, java.lang.Class<? extends T> objectClass)
Determines if the given collection contains an object that is an instance of the given class.- Type Parameters:
T
- The type of the elements contained on the collection.- Parameters:
collection
- The collection to search.objectClass
- The class for which to find an implementing object.- Returns:
true
if the collection contains an object that implements the given class, elsefalse
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createHashSet
public static <E> java.util.HashSet<E> createHashSet(E... elements)
Creates a hash set of the given generic type and initializes it with the given elements.- Type Parameters:
E
- The type of elements the hash set will contain.- Parameters:
elements
- The elements with which to initialize the hash set.- Returns:
- A new hash set containing the given elements.
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get
public static <T> T get(java.util.Collection<T> collection)
Retrieves the first iterated object, if any, from the collection.- Type Parameters:
T
- The type of object stored in the collection.- Parameters:
collection
- The collection from which the object should be retrieved.- Returns:
- The first iterated object from the collection, or
null
if the collection is empty. - Throws:
java.lang.NullPointerException
- if the given collection isnull
.- See Also:
Collection.isEmpty()
,Collection.iterator()
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get
public static <T> T get(java.lang.Iterable<T> iterable)
Retrieves the first iterated object, if any, from the iterable.- Type Parameters:
T
- The type of object stored in the iterable.- Parameters:
iterable
- The iterable from which the object should be retrieved.- Returns:
- The first iterated object from the iterable, or
null
if the iterable is empty. - Throws:
java.lang.NullPointerException
- if the given iterable isnull
.- See Also:
Collection.isEmpty()
,Iterable.iterator()
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set
public static <T> boolean set(java.util.Collection<T> collection, java.util.Collection<? extends T> newCollection)
Sets the contents of the collection to the contents of the other given collection. This is a convenience method forCollection.clear()
followed byCollection.addAll(Collection)
.- Type Parameters:
T
- The type of objects in the collection.- Parameters:
collection
- The collection to set.newCollection
- The elements to set in the collection.- Returns:
true
if the collection changed as a result of the call.
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set
public static <T> boolean set(java.util.Collection<T> collection, T... newElements)
Sets the contents of the collection to the contents of the other given collection. This is a convenience method forCollection.clear()
followed byCollections.addAll(Collection, Object...)
.- Type Parameters:
T
- The type of objects in the collection.- Parameters:
collection
- The collection to set.newElements
- The elements to set in the collection.- Returns:
true
if the collection changed as a result of the call.
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isEmpty
public static <T> boolean isEmpty(java.lang.Iterable<T> iterable)
Determines whether the iterable is empty.- Type Parameters:
T
- The type of object stored in the iterable.- Parameters:
iterable
- The iterable from which the object would be retrieved.- Returns:
true
if an iterator returned from the iterable would return zero elements.- Throws:
java.lang.NullPointerException
- if the given iterable isnull
.- See Also:
Collection.isEmpty()
,Iterable.iterator()
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toCollection
public static <T> java.util.Collection<T> toCollection(java.lang.Iterable<T> iterable)
Converts an iterable to a collection. If the iterable is already a collection, it is returned as such. If the the iterable is not already a collection, a new collection is returned with the contents of the iterable.- Type Parameters:
T
- The type of object in the iterable.- Parameters:
iterable
- The iterable to convert.- Returns:
- A collection with the current contents of the iterable.
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toString
public static <T> java.lang.String toString(java.util.Collection<T> collection)
Converts a collection to a string by concatenating the string values of each member of the collection, separated by a comma.- Type Parameters:
T
- The type of the elements contained on the collection.- Parameters:
collection
- The collection to convert to a string.- Returns:
- A string representation of the collection of elements.
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toString
public static <T> java.lang.String toString(java.util.Collection<T> collection, char delimiter)
Converts a collection to a string by concatenating the string values of each member of the collection, separated by the given delimiter character.- Type Parameters:
T
- The type of the elements contained on the collection.- Parameters:
collection
- The collection to convert to a string.delimiter
- The character to place between elements.- Returns:
- A string representation of the collection of elements.
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toString
public static <T> java.lang.String toString(java.util.Collection<T> collection, java.lang.String delimiter)
Converts a collection to a string by concatenating the string values of each member of the collection, separated by the given delimiter.- Type Parameters:
T
- The type of the elements contained on the collection.- Parameters:
collection
- The collection to convert to a string.delimiter
- The character sequence to place between elements.- Returns:
- A string representation of the collection of elements.
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