DiffUtil.java

package javaToolkit.lib.utils;

import java.util.ArrayList;
import java.util.List;

public class DiffUtil {
	
	
    public static List<Integer> getChangedLineNumListInOldVersion(String diffFilePath) {

        List<Integer> changedLineNumList = new ArrayList<>();
        try {
            List<String> diffFileStrList = FileUtil.readFileToLineList(diffFilePath);
            for (String line : diffFileStrList) {
                if (line.startsWith("@@")) {
                    for (String tmp : line.split(" ")) {
                        if (tmp.trim().startsWith("-")) {
                            if (tmp.contains(",")) {
                                changedLineNumList.add(Integer.valueOf(tmp.trim().replace("-", "").split(",")[0]));
                            } else {
                                changedLineNumList.add(Integer.valueOf(tmp.trim().replace("-", "")));
                            }
                        }
                    }
                }
            }
        } catch (Exception e) {
            // TODO: handle exception
            System.out.println(diffFilePath);
            System.exit(0);
        }
        return changedLineNumList;
    }

    public static List<Integer> getChangedLineNumListInNewVersion(String diffFilePath) {

        List<Integer> changedLineNumList = new ArrayList<>();
        try {
            List<String> diffFileStrList = FileUtil.readFileToLineList(diffFilePath);
            for (String line : diffFileStrList) {
                if (line.startsWith("@@")) {
                    for (String tmp : line.split(" ")) {
                        if (tmp.trim().startsWith("+")) {
                            if (tmp.contains(",")) {
                                changedLineNumList.add(Integer.valueOf(tmp.trim().replace("-", "").split(",")[0]));
                            } else {
                                changedLineNumList.add(Integer.valueOf(tmp.trim().replace("-", "")));
                            }
                        }
                    }
                }
            }
        } catch (Exception e) {
            // TODO: handle exception
            System.out.println(diffFilePath);
            System.exit(0);
        }
        return changedLineNumList;
    }

    public static List<String> getModifiedFileList(String diffFilePath) {
        /**
         * can to be further improved in future
         */
        List<String> modifiedFileRelPathList = new ArrayList<String>();
        for (String line : FileUtil.readFileToLineList(diffFilePath)) {
            if (line.startsWith("diff --git ")) {
                // Heuristic
                String fileRelPath = line.replace("diff --git ", "").split(" ")[0].replaceFirst("a/", "").trim();
                modifiedFileRelPathList.add(fileRelPath);
            }
        }
        return modifiedFileRelPathList;
    }

    public static void main(String[] args) {
        String diffFilePath = "/media/sf__3_fix_groups/RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE/delete redundent null check/27769/diff.txt";
        getModifiedFileList(diffFilePath);
    }

}