add apply patch example

Author: dnaumenko

test/examples/diffutils/ApplyPatch.java

@@ -0,0 +1,27 @@
+package diffutils;
+
+import java.io.File;
+import java.util.List;
+
+import difflib.DiffUtils;
+import difflib.Patch;
+import difflib.PatchFailedException;
+
+public class ApplyPatch extends Example {
+    static final String FS = File.separator;
+    static final String ORIGINAL = "test" + FS + "mocks" + FS + "issue10_base.txt";
+    static final String PATCH = "test" + FS + "mocks" + FS + "issue10_patch.txt";
+
+    public static void main(String[] args) throws PatchFailedException {
+        List<String> original = fileToLines(ORIGINAL);
+        List<String> patched  = fileToLines(PATCH);
+
+     // At first, parse the unified diff file and get the patch
+        Patch patch = DiffUtils.parseUnifiedDiff(patched);
+
+        // Then apply the computed patch to the given text
+        List result = DiffUtils.patch(original, patch);
+        System.out.println(result);
+        /// Or we can call patch.applyTo(original). There is no difference.
+    }
+}

test/examples/diffutils/ComputeDifference.java

@@ -1,38 +1,20 @@
 package diffutils;
 
-import java.io.BufferedReader;
 import java.io.File;
-import java.io.FileReader;
-import java.io.IOException;
-import java.util.LinkedList;
 import java.util.List;
 
 import difflib.Delta;
 import difflib.DiffUtils;
 import difflib.Patch;
 
-public class ComputeDifference {
+public class ComputeDifference extends Example {
     static final String FS = File.separator;
-    static final String originalFilename = "test" + FS + "mocks" + FS + "original.txt";
-    static final String revisedFilename = "test" + FS + "mocks" + FS + "revised.txt";
-
-    private static List<String> fileToLines(String filename) {
-        List<String> lines = new LinkedList<String>();
-        String line = "";
-        try {
-            BufferedReader in = new BufferedReader(new FileReader(filename));
-            while ((line = in.readLine()) != null) {
-                lines.add(line);
-            }
-        } catch (IOException e) {
-            e.printStackTrace();
-        }
-        return lines;
-    }
+    static final String ORIGINAL = "test" + FS + "mocks" + FS + "original.txt";
+    static final String RIVISED = "test" + FS + "mocks" + FS + "revised.txt";
 
     public static void main(String[] args) {
-        List<String> original = fileToLines(originalFilename);
-        List<String> revised  = fileToLines(revisedFilename);
+        List<String> original = fileToLines(ORIGINAL);
+        List<String> revised  = fileToLines(RIVISED);
 
         // Compute diff. Get the Patch object. Patch is the container for computed deltas.
         Patch patch = DiffUtils.diff(original, revised);

test/examples/diffutils/Example.java

@@ -0,0 +1,23 @@
+package diffutils;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.LinkedList;
+import java.util.List;
+
+public class Example {
+    public static List<String> fileToLines(String filename) {
+        List<String> lines = new LinkedList<String>();
+        String line = "";
+        try {
+            BufferedReader in = new BufferedReader(new FileReader(filename));
+            while ((line = in.readLine()) != null) {
+                lines.add(line);
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return lines;
+    }
+}