Java Collect Example

java_collection_example.java

import java.util.ArrayList;

public class AList {
   public static void main(String[] args){
      ArrayList<Integer> grades = new ArrayList<Integer>();
      grades.add(100);
      grades.add(90);
      grades.add(80);
      grades.add(70);
      grades.add(60);
      grades.add(50);
      int total = 0;
      for(int i = 0; i < grades.size(); ++i){
	  total += grades.get(i);
      }
	  /*
	  for(Integer grade : grades){
		total += grade;
	  }
	  */
      double average = total /grades.size();
      System.out.println("Size of grades: "+grades.size());
      System.out.println("Average: "+ double);
	  grades.remove(4);
	  System.out.println("New Size:"+ grades.size());
	  grades.add(60);
	  grades.add(50);
	  System.out.println("Newer Size: "+ grades.size());
	  
   }
}


import java.util.HashSet;
public class Names{
	public static void main(String[] args){
		HashSet<String> names = new HashSet<String>();
		name.add("David");
		names.add("Bryan");
		name.add("Cynthia");
		System.out.println("The number of names is "+names.size());
		for(String name : names){
			System.out.println(name);
		}
		name.remove("David");
		name.remove("Raymond");
		String name = "David";
		if(names.contains(name)){
			System.out.println(name + "is in the collection.");
		}else{
			System.out.println(name +" is not in the collection");
		}
		
		for(String n : names){
			System.out.println(n);
		}
		names.clear();
		System.out.println("The number of names is +"names.size());
	}
	
}


import java.util.TreeSet;

public class Alpha{
	public static void main(String[] args){
		names.add("Raymond");
		names.add("Mike");
		names.add("Bryan");
		names.add("Jennifer");
		names.add("Terrill");
		System.out.println("Number of name = "+names.size());
		
		for(String name : names){
			System.out.println(name);
		}
		
		System.out.println("Name before Jannifer "+names.lower("Jennifer"));
		System.out.println("Name after Jannifer "+names.higher("Jennifer"));
		
		System.out.println("First element: "+names.first());
		System.out.println("Last element: "+names.last());
	}
}

//PriorityQueue is abstraction for basic queue line
import java.util.PriorityQueue;

public class Line{
	public static void main(String[] args){
		PriorityQueue<String> line = new PriorityQueue<String>{};
		line.add("David");
		line.add("Cynthia");
		line.add("Raymond");
		line.add("Bryan");
		line.add("Clayton");
		for (String name : line){
			System.out.println(name);
		}
		
		// to remove item from the head
		line.poll();
		for (String name : line){
			System.out.println(name);
		}
		//also remove item/object by using remove method
		line.remove("Raymond");
		for (String name : line){
			System.out.println(name);
		}	
		//peek at the head
		System.out.println("The head: "+name.peek());
	}
	
}


//Simulation of using the above collection. first using TreeSet.
//1. Using a TreeSet to fliter out duplicate words
import java.util.TreeSet;

public class WordList {
	public static void main(String[] args) {
		String text;
		text = " Let no one caught in sin remain Inside the lie of inward shame We fix our eyes upon the cross "
				+ " And run to him who showed great love And bled for us Freely you bled for us Christ is risen from the dead "
				+ " Trampling over death by death Come awake, come awake Come and rise up from the grave Christ is risen from the dead "
				+ " We are one with him again Come awake come awake Come and rise up from the grave Beneath the weight of all our sin "
				+ " You bow to none but heavens will No scheme of hell no scoffer's crown No burden great can hold you down "
				+ " In strength you reign Forever let your church proclaim Christ is risen from the dead Trampling over death by death "
				+ " Come awake come awake Come and rise up from the grave Christ is risen from the dead We are one with him again "
				+ " Come awake come awake Come and rise up from the grave Oh death Where is your sting Oh hell Where is your victory "
				+ " Oh Church Come stand in the light The glory of God has defeated the night Oh death Where is your sting "
				+ " Oh hell Where is your victory Oh Church Come stand in the light Our God is not dead hes alive hes alive "
				+ " Christ is risen from the dead Trampling over death by death Come awake come awake Come and rise up from the grave "
				+ " Christ is risen from the dead We are one with him again Come awake come awake Come and rise up from the grave "

		//text can be put into a file and read
		String[] words = text.split(" ");
		for(String w : words){
			System.out.println(w);
		}
		System.out.println("The number of words :"+ text.length());
		TreeSet<String> = wordList = new TreeSet<String>();
		for(String w : words){
			wordList.add(w);
		}
		System.out.println("The number of unique words :"+ wordList.length());
		for(String w : wordList){
			System.out.println(w);
		}
		
	}

}