Java: Implement command line progress bar

Using \r (carriage return), we can implement simple command line progress bar. \r goes back to the start of the same line.

 

ProgressBarDemo.java

import java.util.concurrent.TimeUnit;

public class ProgressBarDemo {

	private static final int TOTAL_CHARS = 50;

	private static String getChars(int noOfChars, String progressChar) {
		StringBuilder builder = new StringBuilder();

		builder.append("Installing");

		for (int i = 0; i < noOfChars; i++) {
			builder.append(progressChar);
		}

		for (int i = noOfChars; i < TOTAL_CHARS; i++) {
			builder.append(" ");
		}

		return builder.toString();

	}

	private static void sleep(int noOfMilliSeconds) {
		try {
			TimeUnit.MILLISECONDS.sleep(noOfMilliSeconds);
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	private static void printProgressBar() {
		while (true) {
			for (int i = 1; i < TOTAL_CHARS; i++) {
				System.out.print(getChars(i, "."));
				sleep(300);
				System.out.print("\r");
			}
		}
	}

	public static void main(String[] arg) throws Exception {
		printProgressBar();
	}
}

Output

 

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