package com.michaelthomas.set.hashset;

/**
 * @author Michael Thomas (www.michael-thomas.com) michael@michael-thomas.com
 * 
 */

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

/**
 * @author Michael Thomas (www.michael-thomas.com) michael@michael-thomas.com
 * 
 */


public class MyHashSet {
	//NOTE: For learning, you must see the JUnit test file in the /test/ directory and matching package!
	
	Set<String> buildHashSetCarVendors1() {
		Set<String> set = new HashSet<String>();
		set.add("BMW");
		set.add("Ford");
		set.add("Toyota");
		return set;
	}

	Set<String> buildHashSetCarVendors2() {
		Set<String> set = new HashSet<String>();
		set.add("BMW");
		set.add("Mercedes");
		set.add("Chevorlet");
		return set;
	}

	Set<String> buildHashSetWithNulls() {
		Set<String> set = new HashSet<String>();
		set.add("BMW");
		set.add(null);
		return set;
	}

	
	List<String> buildListDuplicateCarVendors() {
		List<String> list = new ArrayList<String>();
		list.add("BMW");
		list.add("Ford");
		list.add("Toyota");
		list.add("Toyota");
		return list;
	}
	
	List<String> buildListDuplicateCarVendors2() {
		List<String> list = new ArrayList<String>();
		list.add("BMW");
		return list;
	}
	

	List<String> removeDupsFromAList( List<String> dupsList) {
		Set<String> unique = new HashSet<String>(dupsList); //Set doesn't allow dups.
		List<String> uniqueList = new ArrayList<String>(unique);  //Convert from set to ArrayList.
		return uniqueList;
	}
	
	Set<String> returnDups( Set<String> set1, Set<String> set2) {
		Set<String> dups = new HashSet<String>();
		Set<String> uniqueSet = new HashSet<String>(set1);
		
		for (Iterator<String> iterator = set2.iterator(); iterator.hasNext();) {
			String string = (String) iterator.next();
			if ( ! uniqueSet.add(string)) { //If the string will not add then it is a dup!
				dups.add(string);
			}
		}
		
		return dups;
	}

	List<String> returnDups( List<String> list1, List<String> list2) {
		Set<String> dups = new HashSet<String>();
		Set<String> uniqueSet = new HashSet<String>();
		
		for (Iterator<String> iterator = list1.iterator(); iterator.hasNext();) {
			String string = (String) iterator.next();
			if ( ! uniqueSet.add(string)) { //If the string will not add then it is a dup!
				dups.add(string);
			}
		}

		for (Iterator<String> iterator = list2.iterator(); iterator.hasNext();) {
			String string = (String) iterator.next();
			if ( ! uniqueSet.add(string)) { //If the string will not add then it is a dup!
				dups.add(string);
			}
		}

		List<String> dupsList = new ArrayList<String>(dups);
		return  dupsList;
	}

	Set<String> ReturnItemsInBothSets(Set<String> set1, Set<String> set2) {
		Set<String> inBothFiles = new HashSet<String>(set1);
		inBothFiles.retainAll(set2); //Keep anything that is in both files! (Dups)
		return inBothFiles;
	}
	
	Set<String> ReturnItemsNotInBothSets(Set<String> set1, Set<String> set2) {
		//Identify items in both files.
		Set<String> inBothFiles = new HashSet<String>(set1);
		inBothFiles.retainAll(set2); //Keep anything that is in both files! (Dups)

		//Create an unique set of all items
		Set<String> notInBothSets = new HashSet<String>(set1); //Create a new set.
		notInBothSets.addAll(set2); //has a unique set of all items.
		//Now remove any items in both
		notInBothSets.removeAll(inBothFiles); //Remove all dups!
		
		return notInBothSets;
	}

}