AmbientMusicUtility.java

package com.mordrum.mcore.common;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.function.Consumer;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

public class AmbientMusicUtility {
    private static Path musicPath = Paths.get(System.getProperty("user.dir") + "/ambience_music/ambience.properties");
    private static URL musicURL;

    static {
        try {
            musicURL = new URL("http://solder.mordrum.com/mods/ambient-music/ambient-music-pokemon.zip");
        } catch (MalformedURLException ignored) {
        }
    }

    public static boolean isMusicPresent() {
        return Files.exists(musicPath);
    }

    public static Thread downloadMusic(Consumer<String> callback) {
        Runnable downloadThread = () -> {
            try {
                HttpURLConnection urlConnection = (HttpURLConnection) musicURL.openConnection();

                // Buffered file download
                ZipInputStream zipInputStream = new ZipInputStream(urlConnection.getInputStream());
                ZipEntry nextEntry;
                while ((nextEntry = zipInputStream.getNextEntry()) != null) {
                    if (nextEntry.isDirectory()) {
                        new File(System.getProperty("user.dir") + "/" + nextEntry.getName()).mkdirs();
                        continue;
                    }
                    callback.accept(nextEntry.getName());
                    FileOutputStream fos = new FileOutputStream(System.getProperty("user.dir") + "/" + nextEntry.getName());
                    final byte[] buffer = new byte[102400];

                    int len;
                    while((len = (zipInputStream.read(buffer))) > 0) {
                        fos.write(buffer, 0, len);
                    }
                    fos.close();
                }
                zipInputStream.close();
                callback.accept(null);
            } catch (IOException e) {
                e.printStackTrace();
            }
        };
        Thread thread = new Thread(downloadThread);
        thread.setName("Music Download Thread");
        thread.start();
        return thread;
    }
}

InstallMusicGUISnippet.java

@Subscribe
    public void onButtonClick(UIButton.ClickEvent event) {
        String buttonID = event.getComponent().getName().toLowerCase();
        if (buttonID.equals("button.no")) {
            Minecraft.getMinecraft().displayGuiScreen(new SomeGUI(null));
        } else if (buttonID.equals("button.yes")) {
            progressLabel.setVisible(true);
            AmbientMusicUtility.downloadMusic((fileName) -> {
                if (fileName == null) this.mc.addScheduledTask(() -> {
                    this.mc.displayGuiScreen(new SomeGUI(null));
                });
                else progressLabel.setText(ChatColor.WHITE + "Downloading... " + fileName);
            });
        }
    }