DualTextProgressBar.java - a text UI for the progress bar in terminal enironments.

DualTextProgressBar.java

package io.github.coderodde.textui.components;

import java.io.IOException;
import org.jline.terminal.Terminal;
import org.jline.terminal.TerminalBuilder;

/**
 * This class implements a simple text UI progress bar.
 */
public final class DualTextProgressBar {
    
    /**
     * Used for computing the progress percentage.
     */
    private static final int HUNDRED_PERCENT = 100;
    
    /**
     * How many characters are needed for representing everything else but the
     * actual progress bar consisting of a number of <code>#</code> or 
     * <code>.</code> characters.
     */
    private static final int CHARACTER_QUOTA = 7;

    /**
     * The number of progress tokens.
     */
    private final int width;
    
    /**
     * The progress percentage. 0 is zero progress, 1 is the full progress.
     */
    private float progress = 0.0f;
    
    public DualTextProgressBar() throws IOException {
        Terminal terminal = TerminalBuilder.builder().system(true).build();
        int terminalWidth = terminal.getColumns();
        this.width = terminalWidth - CHARACTER_QUOTA;
    }
    
    public void setProgress(float p) {
        checkNotNaN(p);
        progress = Math.clamp(p, 0f, 1f);
        clearBar();
        System.out.print((getBar()));
        System.out.flush();
    }
    
    private void checkNotNaN(float f) {
        if (Float.isNaN(f)) {
            throw new IllegalArgumentException("The argument float is NaN.");
        }
    }
    
    private void clearBar() {
        for (int i = 0; i < width + CHARACTER_QUOTA; ++i) {
            System.out.print("\b");
        }
    }
    
    public static void main(String[] args) throws IOException {
        DualTextProgressBar bar = new DualTextProgressBar();
        
        for (float f = 0.0f; f <= 1.005f; f += 0.01f) {
            bar.setProgress(f);
            
            try {
                Thread.sleep(100L);
            } catch (InterruptedException ignored) {
                
            }
        }
    }
    
    private String getBar() {
        int nFilled      = (int)(progress * width);
        int nFilledRight = nFilled / 2;
        int nFilledLeft  = nFilled - nFilledRight;
        int nNonFilled   = width - nFilled;
        
        StringBuilder sb =
            new StringBuilder(width + CHARACTER_QUOTA).append("[");
        
        sb.append(String.format("%3d%% ", (int) (HUNDRED_PERCENT * progress)));
        
        for (int i = 0; i < nFilledLeft; ++i) {
            sb.append("#");
        }
        
        for (int i = 0; i < nNonFilled; ++i) {
            sb.append(".");
        }
        
        for (int i = 0; i < nFilledRight; ++i) {
            sb.append("#");
        }
        
        return sb.append("]").toString();
    }
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>io.github.coderodde.textui.components</groupId>
    <artifactId>DualTextProgressBar.java</artifactId>
    <version>1.0</version>
    <packaging>jar</packaging>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.release>21</maven.compiler.release>
        <exec.mainClass>io.github.coderodde.textui.components.DualTextProgressBar</exec.mainClass>
    </properties>
    <name>DualTextProgressBar.java</name>
    
    <dependencies>
        <dependency>
            <groupId>org.jline</groupId>
            <artifactId>jline</artifactId>
            <version>4.2.1</version>
        </dependency>
    </dependencies>
    
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>3.4.2</version>
                <configuration>
                    <archive>
                        <manifest>
                            <mainClass>
                                io.github.coderodde.textui.components.DualTextProgressBar
                            </mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
            
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.6.2</version>

                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <createDependencyReducedPom>false</createDependencyReducedPom>
                            <transformers>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>io.github.coderodde.textui.components.DualTextProgressBar</mainClass>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>