Class PredicatedBag
- java.lang.Object
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- All Implemented Interfaces:
java.io.Serializable
,java.lang.Iterable
,java.util.Collection
,Bag
- Direct Known Subclasses:
PredicatedSortedBag
public class PredicatedBag extends PredicatedCollection implements Bag
Decorates anotherBag
to validate that additions match a specified predicate.This bag exists to provide validation for the decorated bag. It is normally created to decorate an empty bag. If an object cannot be added to the bag, an IllegalArgumentException is thrown.
One usage would be to ensure that no null entries are added to the bag.
Bag bag = PredicatedBag.decorate(new HashBag(), NotNullPredicate.INSTANCE);
This class is Serializable from Commons Collections 3.1.
- Since:
- Commons Collections 3.0
- Version:
- $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description private static long
serialVersionUID
Serialization version-
Fields inherited from class org.apache.commons.collections.collection.PredicatedCollection
predicate
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Fields inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator
collection
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Constructor Summary
Constructors Modifier Constructor Description protected
PredicatedBag(Bag bag, Predicate predicate)
Constructor that wraps (not copies).
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
add(java.lang.Object object, int count)
AddsnCopies
copies of the specified object to the Bag.static Bag
decorate(Bag bag, Predicate predicate)
Factory method to create a predicated (validating) bag.protected Bag
getBag()
Gets the decorated bag.int
getCount(java.lang.Object object)
Returns the number of occurrences (cardinality) of the given object currently in the bag.boolean
remove(java.lang.Object object, int count)
RemovesnCopies
copies of the specified object from the Bag.java.util.Set
uniqueSet()
Returns aSet
of unique elements in the Bag.-
Methods inherited from class org.apache.commons.collections.collection.PredicatedCollection
add, addAll, decorate, validate
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Methods inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator
clear, contains, containsAll, equals, getCollection, hashCode, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toArray, toString
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.apache.commons.collections.Bag
add, containsAll, iterator, remove, removeAll, retainAll, size
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Field Detail
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serialVersionUID
private static final long serialVersionUID
Serialization version- See Also:
- Constant Field Values
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Constructor Detail
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PredicatedBag
protected PredicatedBag(Bag bag, Predicate predicate)
Constructor that wraps (not copies).If there are any elements already in the bag being decorated, they are validated.
- Parameters:
bag
- the bag to decorate, must not be nullpredicate
- the predicate to use for validation, must not be null- Throws:
java.lang.IllegalArgumentException
- if bag or predicate is nulljava.lang.IllegalArgumentException
- if the bag contains invalid elements
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Method Detail
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decorate
public static Bag decorate(Bag bag, Predicate predicate)
Factory method to create a predicated (validating) bag.If there are any elements already in the bag being decorated, they are validated.
- Parameters:
bag
- the bag to decorate, must not be nullpredicate
- the predicate to use for validation, must not be null- Returns:
- a new predicated Bag
- Throws:
java.lang.IllegalArgumentException
- if bag or predicate is nulljava.lang.IllegalArgumentException
- if the bag contains invalid elements
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getBag
protected Bag getBag()
Gets the decorated bag.- Returns:
- the decorated bag
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add
public boolean add(java.lang.Object object, int count)
Description copied from interface:Bag
AddsnCopies
copies of the specified object to the Bag.If the object is already in the
Bag.uniqueSet()
then increment its count as reported byBag.getCount(Object)
. Otherwise add it to theBag.uniqueSet()
and report its count asnCopies
.
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remove
public boolean remove(java.lang.Object object, int count)
Description copied from interface:Bag
RemovesnCopies
copies of the specified object from the Bag.If the number of copies to remove is greater than the actual number of copies in the Bag, no error is thrown.
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uniqueSet
public java.util.Set uniqueSet()
Description copied from interface:Bag
Returns aSet
of unique elements in the Bag.Uniqueness constraints are the same as those in
Set
.
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getCount
public int getCount(java.lang.Object object)
Description copied from interface:Bag
Returns the number of occurrences (cardinality) of the given object currently in the bag. If the object does not exist in the bag, return 0.
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