Command line progress bar in Java

Question

I have a Java program running in command line mode. I would like to display a progress bar, showing the percentage of job done. The same kind of progress bar you would see u

Answer 1

I edited Eoin Campbell's code to java and added formatted progress in percents.

public static String progressBar(int currentValue, int maxValue) {
    int progressBarLength = 33; //
    if (progressBarLength < 9 || progressBarLength % 2 == 0) {
        throw new ArithmeticException("formattedPercent.length() = 9! + even number of chars (one for each side)");
    }
    int currentProgressBarIndex = (int) Math.ceil(((double) progressBarLength / maxValue) * currentValue);
    String formattedPercent = String.format(" %5.1f %% ", (100 * currentProgressBarIndex) / (double) progressBarLength);
    int percentStartIndex = ((progressBarLength - formattedPercent.length()) / 2);

    StringBuilder sb = new StringBuilder();
    sb.append("[");
    for (int progressBarIndex = 0; progressBarIndex < progressBarLength; progressBarIndex++) {
        if (progressBarIndex <= percentStartIndex - 1
        ||  progressBarIndex >= percentStartIndex + formattedPercent.length()) {
            sb.append(currentProgressBarIndex <= progressBarIndex ? " " : "=");
        } else if (progressBarIndex == percentStartIndex) {
            sb.append(formattedPercent);
        }
    }
    sb.append("]");
    return sb.toString();
}

int max = 22;
System.out.println("Generating report...");
for (int i = 0; i <= max; i++) {
   Thread.sleep(100);
   System.out.print(String.format("\r%s", progressBar(i, max)));
}
System.out.println("\nSuccessfully saved 32128 bytes");

And output:

Generating report...

[========      24.2 %             ]

[============  45.5 %             ]

[============  78.8 % =====       ]

[============  87.9 % ========    ]

[============ 100.0 % ============]

Successfully saved 32128 bytes