import java.io.File;

import java.io.IOException;

import java.nio.file.Files;

import java.nio.file.Paths;

import java.util.ArrayList;

import java.util.List;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

public class CodeInstrumenter {

public static void instrumentFile(String filePath, String instrumentationCode) throws IOException {

// Read file contents

String fileContent = new String(Files.readAllBytes(Paths.get(filePath)));

// Construct the instrumentation code

String instrumentation = instrumentationCode;

// Find the end of the file (simple approach - might need refinement)

int fileEnd = fileContent.length();

// Inject instrumentation at the end of the file

String instrumentedContent = fileContent + System.lineSeparator() + instrumentation;

// Write the instrumented content back to the file

Files.write(Paths.get(filePath), instrumentedContent.getBytes());

}

public static void main(String[] args) throws IOException {

//Example Usage

//Instrumentation code to be added to the end of the file

String instrumentationCode = "System.out.println(\"File instrumented!\");";

//File path to the legacy project file

String filePath = "legacy_file.java";

//Create a dummy file for testing

File file = new File(filePath);

if (!file.exists()) {

try {

Files.write(Paths.get(filePath), "public class LegacyClass {\n public void legacyMethod() {}\n}".getBytes());

} catch (IOException e) {

System.err.println("Error creating dummy file: " + e.getMessage());

return;

}

}

instrumentFile(filePath, instrumentationCode);

}

}