Java Tutorial/Collections/LinkedHashSet

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());
    }
  }
}

Putting your own type in a LinkedHashSet

import java.util.LinkedHashSet;
import java.util.Set;
public class MainClass {
  public static Set fill(Set a, int size) {
    for (int i = 0; i < size; i++)
      a.add(new MyType(i));
    return a;
  }
  public static void test(Set a) {
    fill(a, 10);
    fill(a, 10); // Try to add duplicates
    fill(a, 10);
    System.out.println(a);
  }
  public static void main(String[] args) {
    test(new LinkedHashSet());
  }
}
class MyType implements Comparable {
  private int i;
  public MyType(int n) {
    i = n;
  }
  public boolean equals(Object o) {
    return (o instanceof MyType) && (i == ((MyType) o).i);
  }
  public int hashCode() {
    return i;
  }
  public String toString() {
    return i + " ";
  }
  public int compareTo(Object o) {
    int i2 = ((MyType) o).i;
    return (i2 < i ? -1 : (i2 == i ? 0 : 1));
  }
}
//

[0 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]

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);
  }
}