Chapter 12 Ex 29

Author: HarryDulaney

src/ch_12/exercise12_29/Exercise12_29.java

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+package ch_12.exercise12_29;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Objects;
+import java.util.regex.Pattern;
+
+/**
+ * **12.29 (Rename files) Suppose you have a lot of files in a directory named Exercisei_j,
+ * where i and j are digits. Write a program that pads a 0 before j if j is a single
+ * digit. For example, a file named Exercise2_1 in a directory will be renamed to
+ * Exercise2_01. In Java, when you pass the symbol * from the command line,
+ * it refers to all files in the directory (see Supplement III.V). Use the following
+ * command to run your program.
+ * To test:
+ * rename files in ./testDir by removing the '0' padding in the suffix for j.
+ * <p>
+ * (From inside: java-prog-dan-lang-10th/src/ch_12/exercise12_29/ ) cmd: javac Exercise12_29.java
+ * cmd: cd ../..
+ * cmd: java ch_12.exercise12_29.Exercise12_29 *
+ */
+public class Exercise12_29 {
+    private static final Pattern PATTERN = Pattern.compile("Exercise\\d{1,2}_\\d.*"); //
+
+    public static void main(String[] args) {
+
+        if (args.length < 1) {
+            System.out.println("Usage: java Exercise12_29 *");
+            return;
+        }
+        if (!args[0].equals("*")) {
+            System.out.println("Usage: java Exercise12_29 *");
+            return;
+        }
+
+        File srcDirectory = new File("./testDir");
+        if (!srcDirectory.isDirectory()) {
+            System.out.println("The directory path is not a directory: " + srcDirectory.getAbsolutePath());
+            return;
+        }
+
+        if (!Objects.isNull(srcDirectory.listFiles()) && srcDirectory.listFiles().length > 0) {
+            ArrayList<File> files = new ArrayList<>(Arrays.asList(srcDirectory.listFiles()));
+            for (File f : files) {
+                String fileName = f.getName();
+                StringBuffer stringBuffer = new StringBuffer(fileName);
+                if (PATTERN.matcher(stringBuffer.toString()).matches()) {
+                    stringBuffer.insert(fileName.lastIndexOf("_") + 1, "0");
+                    System.out.println("Renaming: " + fileName + " to " + stringBuffer.toString());
+                    Path srcPath = f.toPath();
+                    Path trgtPath = Paths.get(srcDirectory.toPath().toString(), stringBuffer.toString());
+                    try {
+                        Files.move(srcPath, trgtPath, StandardCopyOption.REPLACE_EXISTING);
+                        System.out.println("Rename successful");
+                    } catch (IOException ioe) {
+                        System.out.println("Something went wrong while renaming the file... " + fileName + "\n\n");
+                        ioe.printStackTrace();
+                    }
+
+                }
+
+            }
+        } else {
+            System.out.println("The current directory is empty...");
+        }
+
+    }
+}

src/ch_12/exercise12_29/testDir/Exercise01_01.txt

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+Random file

src/ch_12/exercise12_29/testDir/Exercise01_02.txt

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+file file file

src/ch_12/exercise12_29/testDir/Exercise01_03.txt

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+fileeeeee