HashBag

Data Structure

HashBag is a collection that knows the number of times an object appears in it. HashBag described here is an apache collection class. HashBag internally depends on HashMap. The Object to store becomes they Key and the no. of copies becomes the Value.

HashBag

Add

First time the Object is added, its no. of copies will be initialized to 1.

HashBag

When an Object is added to the bag, it delegates the call to HashMap. The Object will be added as the Key, its hash code will be used to identify the array element.

HashBag

If we add an existing Object, its no. of copies will be incremented by the no. of copies added. If we just call add(Object) , no. of copies will be incremented by one.

HashBag

HashBag

Class Diagram

HashBag internally uses HashMap where the Object is the key and its value, a Mutable Integer to keep track of the count of objects in the collection.

HashBag

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