Simple console unlimited progress bar

ConsoleUnlimitedProgressBar.java

import java.io.IOException;

/**
 * Simple console unlimited progress bar
 *
 * Usage:
 *
 * 	ConsoleUnlimitedProgressBar progressBar = new ConsoleUnlimitedProgressBar();
 *	int counter = 0;
 * 	while (true) {
 *		progressBar.progress(counter++);
 *		Thread.sleep(100);
 *	}
 */
public final class ConsoleUnlimitedProgressBar {
	private static final String BEGIN = "\r|";
	private static final char END = '|';
	private static final char EMPTY = '-';
	private static final char FILL = '*';
	private static final int OFFSET = BEGIN.length();
	private static final int LENGTH = 60;

	private final String template = createTemplate();
	private final int maxPosition = template.length() - OFFSET;
	private final int minPosition = OFFSET;
	private int position = minPosition - 1;
	private boolean reverse = false;

	public void progress(int value) {
		processPosition();
		String s = buildProgressBarString(value);
		printProgressBar(s);
		checkDirection();
	}

	private void processPosition() {
		if (!reverse) {
			position++;
		} else {
			position--;
		}
	}

	private void checkDirection() {
		if (!reverse) {
			if (position >= maxPosition) {
				reverse = true;
				position = maxPosition;
			}
		} else {
			if (position <= minPosition) {
				reverse = false;
				position = minPosition;
			}
		}
	}

	private String buildProgressBarString(int value) {
		StringBuilder sb = new StringBuilder();
		sb.append(template.substring(0, position));
		sb.append(FILL);
		sb.append(template.substring(position + 1, template.length()));
		sb.append(": ");
		sb.append(value);
		return sb.toString();
	}

	private static void printProgressBar(String s) {
		try {
			System.out.write(s.getBytes());
		} catch (IOException e) {
			throw new RuntimeException(e);
		}
	}

	private static String createTemplate() {
		StringBuilder sb = new StringBuilder(BEGIN);
		for (int i = 0; i< LENGTH; i++) {
			sb.append(EMPTY);
		}
		sb.append(END);
		return sb.toString();
	}
}