Java LinkedList Collection Framework

What is a LinkedList ? LinkedList is a class extend from java.util.AbstractSequentialList and implement the interface List and Deque, this framework is used to handle the type of data structures stack and queue. In this post I will not discuss about the stack and queue. so I just focus on How to Implement Stack & Queue in Java.

Why use a LinkedList ?
1. An unlimited number of elements
2. The number of elements that are flexible. When an index removed, the total index on the index will also change so none index is empty.
3. Able to handle the data structure of type stack, queue

Some of the most common method used in the LinkedList object:
1. Adding Element Methods

RETURN	METHODE	STACK	QUEUE	EXPLAIN
boolean	add(E e)		*	Appends the specified element to the end of this list
void	addFirst(E e)		*	Inserts the specified element at the beginning of this list.
void	addLast(E e)		*	Appends the specified element to the end of this list.
boolean	offer(E e)		*	Adds the specified element as the tail (last element) of this list.
boolean	offerFirst(E e)		*	Inserts the specified element at the front of this list.
boolean	offerLast(E e)		*	Inserts the specified element at the end of this list.
void	push(E e)	*		Pushes an element onto the stack represented by this list.

2. Get Element Methods

RETURN	METHODE	STACK	QUEUE	EXPLAIN
E	get(int index)	*	*	Returns the element at the specified position in this list.
E	getFirst()	*	*	Returns the first element in this list.
E	getLast()	*	*	Returns the last element in this list.
E	peek()		*	Retrieves, but does not remove, the head (first element) of this list.
E	peekFirst()		*	Retrieves, but does not remove, the first element of this list, or returns `null` if this list is empty.
E	peekLast		*	Retrieves, but does not remove, the last element of this list, or returns `null` if this list is empty.

3. Remove Element Methods

RETURN	METHODE	STACK	QUEUE	EXPLAIN
E	poll()		*	Retrieves and removes the head (first element) of this list
E	pollFirst()		*	Retrieves and removes the first element of this list, or returns `null` if this list is empty.
E	pollLast()		*	Retrieves and removes the last element of this list, or returns `null` if this list is empty.
E	remove(int index)	*	*	Removes the element at the specified position in this list.
E	removeFirst()	*	*	Removes and returns the first element from this list.
E	removeLast()	*	*	Removes and returns the last element from this list.
E	pop()	*		Pops an element from the stack represented by this list.

PRACTICE

Class Person

package person;
/**
*
* @author Faicker Himmah
*/
public class Person {
    String name;
    String address;
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

STACK

Insert Element

//create object LinkedList to contain object Person
LinkedList<Person> linked = new LinkedList<Person>();

        Person p1 = new Person();
        p1.setName("Ar-Rohman Software House");
        p1.setAddress("Malang");
        Person p2 = new Person();
        p2.setName("Jasa Pembuatan Software");
        p2.setAddress("Malang");
        Person p3 = new Person();
        p3.setName("Faiqul Himmah");
        p3.setAddress("Malang");
        Person p4 = new Person();
        p4.setName("Zahroul Ulum");
        p4.setAddress("Malang");
        // insert object Person into linked
        linked.push(p1);
        linked.push(p2);
        linked.push(p3);
        linked.push(p4);
       for(Person p : linked){
            System.out.println("Name : "+p.getName());
            System.out.println("Address : "+p.getAddress());
        }

Remove Element

linked.pop() //remove last inserted

QUEUE

Insert Element

//create object LinkedList to contain object Person
LinkedList<Person> linked = new LinkedList<Person>();
        ArrayList<Person> list = new ArrayList<Person>();
        Person p1 = new Person();
        p1.setName("Ar-Rohman Software House");
        p1.setAddress("Malang");
        Person p2 = new Person();
        p2.setName("Jasa Pembuatan Software");
        p2.setAddress("Malang");
        Person p3 = new Person();
        p3.setName("Faiqul Himmah");
        p3.setAddress("Malang");
        Person p4 = new Person();
        p4.setName("Zahroul Ulum");
        p4.setAddress("Malang");
        // insert object Person into linked
        linked.add(p1);
        linked.add(p2);
        linked.add(p3);
        linked.add(p4);
       for(Person p : linked){
            System.out.println("Name : "+p.getName());
            System.out.println("Address : "+p.getAddress());
        }

Remove Element

linked.poll(); //remove first inserted

CONCLUSION
What is the difference ArrayList & Linked List ?

	ArrayList	LinkedList
An unlimited number of elements	*	*
The number of elements that are flexible	*	*
Able to handle the data structure of type stack, queue		*
Implemeted interface List	*	*
Implemeted interface Deque		*