Class AbstractMapBag<E>
java.lang.Object
org.apache.commons.collections4.bag.AbstractMapBag<E>
- Type Parameters:
E- the type of elements in this bag
- All Implemented Interfaces:
Iterable<E>,Collection<E>,Bag<E>
Abstract implementation of the
Bag interface to simplify the creation
of subclass implementations.
Subclasses specify a Map implementation to use as the internal storage. The map will be used to map bag elements to a number; the number represents the number of occurrences of that element in the bag.
- Since:
- 3.0 (previously DefaultMapBag v2.0)
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprotected static classMutable integer class for storing the data. -
Constructor Summary
ConstructorsModifierConstructorDescriptionprotectedConstructor needed for subclass serialization.protectedConstructor that assigns the specified Map as the backing store.protectedAbstractMapBag(Map<E, AbstractMapBag.MutableInteger> map, Iterable<? extends E> iterable) Constructs a new instance that assigns the specified Map as the backing store. -
Method Summary
Modifier and TypeMethodDescriptionbooleanAdds a new element to the bag, incrementing its count in the underlying map.booleanAdds a new element to the bag, incrementing its count in the map.booleanaddAll(Collection<? extends E> coll) Invokesadd(Object)for each element in the given collection.voidclear()Clears the bag by clearing the underlying map.booleanDetermines if the bag contains the given element by checking if the underlying map contains the element as a key.booleancontainsAll(Collection<?> coll) Determines if the bag contains the given elements.protected voidReads the map in using a custom routine.protected voidWrites the map out using a custom routine.booleanCompares this Bag to another.intGets the number of occurrence of the given element in this bag by looking up its count in the underlying map.protected Map<E, AbstractMapBag.MutableInteger> getMap()Utility method for implementations to access the map that backs this bag.inthashCode()Gets a hash code for the Bag compatible with the definition of equals.booleanisEmpty()Returns true if the underlying map is empty.iterator()Gets an iterator over the bag elements.booleanRemoves all copies of the specified object from the bag.booleanRemoves a specified number of copies of an object from the bag.booleanremoveAll(Collection<?> coll) Removes objects from the bag according to their count in the specified collection.booleanretainAll(Collection<?> coll) Remove any members of the bag that are not in the given bag, respecting cardinality.intsize()Returns the number of elements in this bag.Object[]toArray()Returns an array of all of this bag's elements.<T> T[]toArray(T[] array) Returns an array of all of this bag's elements.toString()Implement a toString() method suitable for debugging.Returns an unmodifiable view of the underlying map's key set.Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, waitMethods inherited from interface java.util.Collection
parallelStream, removeIf, spliterator, stream
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Constructor Details
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AbstractMapBag
protected AbstractMapBag()Constructor needed for subclass serialization. -
AbstractMapBag
Constructor that assigns the specified Map as the backing store. The map must be empty and non-null.- Parameters:
map- the map to assign
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AbstractMapBag
Constructs a new instance that assigns the specified Map as the backing store. The map must be empty and non-null. The bag is filled from the iterable elements.- Parameters:
map- the map to assign.iterable- The bag is filled from these iterable elements.
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Method Details
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add
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add
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addAll
Invokesadd(Object)for each element in the given collection.- Specified by:
addAllin interfaceCollection<E>- Parameters:
coll- the collection to add- Returns:
trueif this call changed the bag
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clear
Clears the bag by clearing the underlying map.- Specified by:
clearin interfaceCollection<E>
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contains
Determines if the bag contains the given element by checking if the underlying map contains the element as a key.- Specified by:
containsin interfaceCollection<E>- Parameters:
object- the object to search for- Returns:
- true if the bag contains the given element
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containsAll
Determines if the bag contains the given elements.- Specified by:
containsAllin interfaceBag<E>- Specified by:
containsAllin interfaceCollection<E>- Parameters:
coll- the collection to check against- Returns:
trueif the Bag contains all the collection
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doReadObject
protected void doReadObject(Map<E, AbstractMapBag.MutableInteger> map, ObjectInputStream in) throws IOException, ClassNotFoundExceptionReads the map in using a custom routine.- Parameters:
map- the map to usein- the input stream- Throws:
IOException- any of the usual I/O related exceptionsClassNotFoundException- if the stream contains an object which class cannot be loadedClassCastException- if the stream does not contain the correct objects
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doWriteObject
Writes the map out using a custom routine.- Parameters:
out- the output stream- Throws:
IOException- any of the usual I/O related exceptions
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equals
Compares this Bag to another. This Bag equals another Bag if it contains the same number of occurrences of the same elements.- Specified by:
equalsin interfaceCollection<E>- Overrides:
equalsin classObject- Parameters:
object- the Bag to compare to- Returns:
- true if equal
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getCount
Gets the number of occurrence of the given element in this bag by looking up its count in the underlying map. -
getMap
Utility method for implementations to access the map that backs this bag. Not intended for interactive use outside of subclasses.- Returns:
- the map being used by the Bag
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hashCode
Gets a hash code for the Bag compatible with the definition of equals. The hash code is defined as the sum total of a hash code for each element. The per element hash code is defined as(e==null ? 0 : e.hashCode()) ^ noOccurrences). This hash code is compatible with the Set interface.- Specified by:
hashCodein interfaceCollection<E>- Overrides:
hashCodein classObject- Returns:
- the hash code of the Bag
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isEmpty
Returns true if the underlying map is empty.- Specified by:
isEmptyin interfaceCollection<E>- Returns:
- true if bag is empty
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iterator
Gets an iterator over the bag elements. Elements present in the Bag more than once will be returned repeatedly. -
remove
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remove
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removeAll
Removes objects from the bag according to their count in the specified collection. -
retainAll
Remove any members of the bag that are not in the given bag, respecting cardinality. -
size
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toArray
Returns an array of all of this bag's elements.- Specified by:
toArrayin interfaceCollection<E>- Returns:
- an array of all of this bag's elements
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toArray
Returns an array of all of this bag's elements. If the input array has more elements than are in the bag, trailing elements will be set to null.- Specified by:
toArrayin interfaceCollection<E>- Type Parameters:
T- the type of the array elements- Parameters:
array- the array to populate- Returns:
- an array of all of this bag's elements
- Throws:
ArrayStoreException- if the runtime type of the specified array is not a supertype of the runtime type of the elements in this listNullPointerException- if the specified array is null
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toString
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uniqueSet
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