BLOB.java

import java.io.File;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class BLOB {
    public static String getFileContents(File file) {

        StringBuilder content = new StringBuilder();
        try (BufferedReader br = new BufferedReader(new FileReader(file))) {
            String line;
            while ((line = br.readLine()) != null) {
                content.append(line).append("\n");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return content.toString();
    }

    public static void copyToBlob(String fileContents, File newFile) {
        try (BufferedWriter writer = new BufferedWriter(new FileWriter(newFile))) {
            writer.write(fileContents);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static String addFile(String path) {
        File index = new File("git" + File.separator + "index");
        updateIndexFile(path, index, "blob");
        return createBlob(path);
    }

    public static String createBlob(String path) {
        String fileContents = getFileContents(new File(path));
        String key = SHA1.encryptThisString(fileContents);
        File BLOB = new File("git" + File.separator + "objects" + File.separator + key);
        try {
            BLOB.createNewFile();
        } catch (IOException e) {
            System.out.println(e);
        }
        copyToBlob(fileContents, BLOB);
        return "git" + File.separator + "objects" + File.separator + key;
    }

    public static void updateIndexFile(String path, File index, String type) {
        String fileContents = getFileContents(new File(path));
        String hash = SHA1.encryptThisString(fileContents);
        try {
            if (index.length() == 0) {
                try (BufferedWriter writer = new BufferedWriter(new FileWriter(index))) {
                    writer.write(type + " " + hash + " " + path);
                }
            } else {
                try (BufferedWriter writer = new BufferedWriter(new FileWriter(index, true))) {
                    writer.newLine();
                    writer.write(type + " " + hash + " " + path);
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}