Advanced Java Programming

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Advanced Java Programming

• CSS446
• Spring 2014
• Nan Wang

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Chapter Goals

• Java Collection Framework
• LinkedList
• Set
• Map

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Collection

• When you need to organize multiple objects in
  your program, you can place them into a
  collection.
• A collection groups together elements and allows
  them to be retrieved later.
• ArrayList

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Java Collections Framework

• A hierarchy of interface types and classes for
  collecting objects. Each interface type is
  implemented by one or more classes.

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List

• a list is a collection that remembers the order
  of its elements.

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ArrayList

• The ArrayList class implements the List
  interface.
• An ArrayList is simply a class containing an
  array that is expanded as needed.
• If you are not concerned about efficiency, you
  can use the ArrayList class whenever you need to
  collect objects. However, several common
  operations are inefficient with array lists. In
  particular, if an element is added or removed,
  the elements at larger positions must be moved.

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Insertion and Deletion of ArrayList
element
element
element
element
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Set

• Set is an unordered collection of unique
  elements.
• Because a set does not track the order of the
  elements, so the operations of finding, adding
  and removing are more efficient.

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Stack

• A stack remembers the order of its elements, but
  it does not allow you to insert elements in every
  position.
• You can add and remove elements only at the top.

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Queue

• In a queue, you add items to one end (the tail)
  and remove them from the other end (the head).
• A priority queue is an unordered collection that
  has an efficient operation for removing the
  element with the highest priority. (reading
  assignments)

front
rear
rear
rear
rear
rear
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Map

• A map keeps associations between key and value
  objects.

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LinkedList

• A linked list uses a sequence of nodes.
• A node is an object that stores an element and
  references to the neighboring nodes in the
  sequence

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LinkedList Insert and delete
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LinkedList Class

• It is a generic class, that you specify the type
  of the list elements in angle brackets.

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List Iterators

• List iterators are used to access elements inside
  a linked list.
• you should think of the iterator as pointing
  between two elements, just as the cursor in a
  word processor points between two characters

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List Iterators

• Obtain a list iterator with the listIterator() of
  the LinkedList class.

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Review Questions
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