add random util

Author: maxxbw

lib/utils/DiffUtil.java

@@ -5,48 +5,50 @@
 
 public class DiffUtil {
 
-	public static int getChangedLine(String diffFilePath) {
-		try {
-			List<String> diffFileStrList = FileUtil.readFileToStrList(diffFilePath);
-			for (String line : diffFileStrList) {
-				if (line.startsWith("@@")) {
-					for (String tmp : line.split(" ")) {
-						if (tmp.trim().startsWith("-")) {
-							if (tmp.contains(",")) {
-								return Integer.valueOf(tmp.trim().replace("-", "").split(",")[0]);
-							} else {
-								return Integer.valueOf(tmp.trim().replace("-", ""));
-							}
-						}
-					}
-				}
-			}
-		} catch (Exception e) {
-			// TODO: handle exception
-			System.out.println(diffFilePath);
-			System.exit(0);
-		}
-		return -1;
-	}
+    public static List<Integer> getChangedLineNumList(String diffFilePath) {
 
-	public static List<String> getModifiedFileList(String diffFilePath) {
-		/**
-		 * can to be further improved in future
-		 */
-		List<String> modifiedFileRelPathList = new ArrayList<String>();
-		for (String line : FileUtil.readFileToStrList(diffFilePath)) {
-			if (line.startsWith("diff --git ")) {
-				// Heuristic
-				String fileRelPath = line.replace("diff --git ", "").split(" ")[0].replaceFirst("a/", "").trim();
-				modifiedFileRelPathList.add(fileRelPath);
-			}
-		}
-		return modifiedFileRelPathList;
-	}
+        List<Integer> changedLineNumList = new ArrayList<>();
+        try {
+            List<String> diffFileStrList = FileUtil.readFileToStrList(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 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);
-	}
+    public static List<String> getModifiedFileList(String diffFilePath) {
+        /**
+         * can to be further improved in future
+         */
+        List<String> modifiedFileRelPathList = new ArrayList<String>();
+        for (String line : FileUtil.readFileToStrList(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);
+    }
 
 }

lib/utils/FileUtil.java

@@ -21,6 +21,20 @@
 
 public class FileUtil {
 
+	public static String getFileContent(String filePath) throws IOException {
+
+		BufferedReader br=new BufferedReader(new FileReader(filePath));
+		StringBuilder sb=new StringBuilder();
+		String line=br.readLine();
+		while(line!=null){
+			sb.append(line);
+			sb.append(System.lineSeparator());
+			line=br.readLine();
+		}
+		return sb.toString();
+
+	}
+
 	public static String[] getSubDirs(String rootDir) {
 
 		File file = new File(rootDir);

lib/utils/JSONUtil.java

@@ -10,7 +10,7 @@
 public class JSONUtil {
 
 	public static JSONObject parseJSONFromFile(String jsonFpath) {
-		FileReader reader = null;
+		FileReader reader;
 		JSONObject object = null;
 		try {
 			reader = new FileReader(jsonFpath);

lib/utils/RandomUtil.java

@@ -0,0 +1,43 @@
+package javaToolkit.lib.utils;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Random;
+
+public class RandomUtil {
+
+    public Object getARandomElement(List<?> givenList) {
+        Random rand = new Random();
+        Object randomElement = givenList.get(rand.nextInt(givenList.size()));
+        return randomElement;
+    }
+
+
+    public List<Object> randomSelectWithRepeat(List<Object> givenList, int numberOfElements) {
+        Random rand = new Random();
+        List<Object> selectedEles = new ArrayList<>();
+
+        for (int i = 0; i < numberOfElements; i++) {
+            int randomIndex = rand.nextInt(givenList.size());
+            Object randomElement = givenList.get(randomIndex);
+            selectedEles.add(randomElement);
+        }
+
+        return selectedEles;
+    }
+
+    public List<?> randomSelectWithoutRepeat(List<?> givenList, int numberOfElements) {
+        Random rand = new Random();
+        List<Object> selectedEles = new ArrayList<>();
+
+        for (int i = 0; i < numberOfElements; i++) {
+            int randomIndex = rand.nextInt(givenList.size());
+            Object randomElement = givenList.get(randomIndex);
+            selectedEles.add(randomElement);
+            givenList.remove(randomIndex);
+        }
+
+        return selectedEles;
+    }
+}