How do I use StringTokenizer to split a string?

By Wayan in Core API, Util Package 0 Comment

The code below is an example of using StringTokenizer to split a string. In the current JDK this class is discouraged to be used, use the String.split(...) method instead or using the new java.util.regex package.

package org.kodejava.util;

import java.util.StringTokenizer;

public class StringTokenizerExample {
    public static void main(String[] args) {
        StringTokenizer st =
            new StringTokenizer("A StringTokenizer sample");

        // get how many tokens inside st object
        System.out.println("Tokens count: " + st.countTokens());

        // iterate st object to get more tokens from it
        while (st.hasMoreElements()) {
            String token = st.nextElement().toString();
            System.out.println("Token = " + token);
        }

        // split a date string using a forward slash as delimiter
        st = new StringTokenizer("2021/09/14", "/");
        while (st.hasMoreElements()) {
            String token = st.nextToken();
            System.out.println("Token = " + token);
        }
    }
}

Here is the result of this sample code:

Tokens count: 3
Token = A
Token = StringTokenizer
Token = sample
Token = 2021
Token = 09
Token = 14

How do I know if an ArrayList contains a specified item?

By Wayan in Core API, Util Package 2 Comments

In this example we are going to learn how to find out if an ArrayList object contains the specified element. To check if an ArrayList object contains the specified element we can use the contains(Object o) method. This method returns a boolean true when the specified element is found in the ArrayList, otherwise return false. The method returns true if and only if the list contains at least one element, where the element equals to the item in the list.

Let’s see the code snippet below to demonstrate it.

package org.kodejava.util;

import java.util.ArrayList;
import java.util.List;

public class ArrayListContainsExample {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        list.add("Item 1");
        list.add("Item 2");
        list.add("Item 3");
        list.add("Item 4");

        // Check to see if the list contains "Item 1".
        String itemToFind = "Item 1";
        System.out.println("contains(" + itemToFind + "): " + list.contains(itemToFind));

        // Check to see if the list contains "Item 20".
        itemToFind = "Item 20";
        System.out.println("contains(" + itemToFind + "): " + list.contains(itemToFind));
    }
}

The output of the code snippet above are:

contains(Item 1): true
contains(Item 20): false