Java/Collections Data Structure/LinkedHashSet

Creating a Set That Retains Order-of-Insertion

 
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Set;
public class Main {
  public static void main(String[] argv) throws Exception {
    Set<String> set = new LinkedHashSet<String>();
    // Add some elements
    set.add("1");
    set.add("2");
    set.add("3");
    set.add("2");
    // List the elements
    for (Iterator it = set.iterator(); it.hasNext();) {
      Object o = it.next();
    }
  }
}

Get Size of Java LinkedHashSet

 
import java.util.LinkedHashSet;
public class Main {
  public static void main(String[] args) {
    LinkedHashSet<Integer> lhashSet = new LinkedHashSet<Integer>();
    System.out.println("Size of LinkedHashSet : " + lhashSet.size());
    lhashSet.add(new Integer("1"));
    lhashSet.add(new Integer("2"));
    lhashSet.add(new Integer("3"));
    System.out.println(lhashSet.size());
    lhashSet.remove(new Integer("1"));
    System.out.println(lhashSet.size());
  }
}

Iterate through elements of Java LinkedHashSet

 
import java.util.Iterator;
import java.util.LinkedHashSet;
public class Main {
  public static void main(String[] args) {
    LinkedHashSet<Integer> lhashSet = new LinkedHashSet<Integer>();
    lhashSet.add(new Integer("1"));
    lhashSet.add(new Integer("2"));
    lhashSet.add(new Integer("3"));
    Iterator itr = lhashSet.iterator();
    while (itr.hasNext()){
      System.out.println(itr.next());
    }
  }
}

Remove all elements from Java LinkedHashSet

 
       
import java.util.LinkedHashSet;
public class Main {
  public static void main(String[] args) {
    LinkedHashSet<Integer> lhashSet = new LinkedHashSet<Integer>();
    lhashSet.add(new Integer("1"));
    lhashSet.add(new Integer("2"));
    lhashSet.add(new Integer("3"));
    System.out.println(lhashSet);
    lhashSet.clear();
    System.out.println(lhashSet);
    System.out.println(lhashSet.isEmpty());
  }
}

Remove specified element from Java LinkedHashSet

 
import java.util.LinkedHashSet;
public class Main {
  public static void main(String[] args) {
    LinkedHashSet<Integer> lhashSet = new LinkedHashSet<Integer>();
    
    lhashSet.add(new Integer("1"));
    lhashSet.add(new Integer("2"));
    lhashSet.add(new Integer("3"));
    System.out.println(lhashSet);
    boolean blnRemoved = lhashSet.remove(new Integer("2"));
    System.out.println(blnRemoved);
    System.out.println(lhashSet);
  }
}

Simple Java LinkedHashSet

 
import java.util.LinkedHashSet;
public class Main {
  public static void main(String[] args) {
    LinkedHashSet<Integer> lhashSet = new LinkedHashSet<Integer>();
    lhashSet.add(new Integer("1"));
    lhashSet.add(new Integer("2"));
    lhashSet.add(new Integer("3"));
    System.out.println(lhashSet);
  }
}