From dd7b922f2bb0e738a3926583cb5199ed888ef793 Mon Sep 17 00:00:00 2001
From: dupirefr <dupire.francois+pro@gmail.com>
Date: Wed, 24 Jul 2019 08:17:58 +0200
Subject: [PATCH] [BAEL-3090] Added example

---
 .../com/baeldung/memento/Coordinates.java     | 12 ++++++++
 .../java/com/baeldung/memento/TextEditor.java | 19 ++++++++++++
 .../java/com/baeldung/memento/TextWindow.java | 30 +++++++++++++++++++
 .../com/baeldung/memento/TextWindowState.java | 14 +++++++++
 4 files changed, 75 insertions(+)
 create mode 100644 patterns/design-patterns-2/src/main/java/com/baeldung/memento/Coordinates.java
 create mode 100644 patterns/design-patterns-2/src/main/java/com/baeldung/memento/TextEditor.java
 create mode 100644 patterns/design-patterns-2/src/main/java/com/baeldung/memento/TextWindow.java
 create mode 100644 patterns/design-patterns-2/src/main/java/com/baeldung/memento/TextWindowState.java

diff --git a/patterns/design-patterns-2/src/main/java/com/baeldung/memento/Coordinates.java b/patterns/design-patterns-2/src/main/java/com/baeldung/memento/Coordinates.java
new file mode 100644
index 0000000000..19c1798a93
--- /dev/null
+++ b/patterns/design-patterns-2/src/main/java/com/baeldung/memento/Coordinates.java
@@ -0,0 +1,12 @@
+package com.baeldung.memento;
+
+public class Coordinates {
+
+    private int x;
+    private int y;
+
+    public Coordinates(int x, int y) {
+        this.x = x;
+        this.y = y;
+    }
+}
diff --git a/patterns/design-patterns-2/src/main/java/com/baeldung/memento/TextEditor.java b/patterns/design-patterns-2/src/main/java/com/baeldung/memento/TextEditor.java
new file mode 100644
index 0000000000..cf08e2b226
--- /dev/null
+++ b/patterns/design-patterns-2/src/main/java/com/baeldung/memento/TextEditor.java
@@ -0,0 +1,19 @@
+package com.baeldung.memento;
+
+public class TextEditor {
+
+    private TextWindow textWindow;
+    private TextWindowState savedTextWindow;
+
+    public TextEditor(TextWindow textWindow) {
+        this.textWindow = textWindow;
+    }
+
+    public void hitSave() {
+        savedTextWindow = textWindow.save();
+    }
+
+    public void hitUndo() {
+        textWindow.restore(savedTextWindow);
+    }
+}
diff --git a/patterns/design-patterns-2/src/main/java/com/baeldung/memento/TextWindow.java b/patterns/design-patterns-2/src/main/java/com/baeldung/memento/TextWindow.java
new file mode 100644
index 0000000000..5fdfda1998
--- /dev/null
+++ b/patterns/design-patterns-2/src/main/java/com/baeldung/memento/TextWindow.java
@@ -0,0 +1,30 @@
+package com.baeldung.memento;
+
+public class TextWindow {
+
+    private StringBuilder currentText;
+    private Coordinates cursorPosition;
+
+    public TextWindow() {
+        this.currentText = new StringBuilder();
+        this.cursorPosition = new Coordinates(0, 0);
+    }
+
+    public void addText(String text) {
+        currentText.append(text);
+    }
+
+    public TextWindowState save() {
+        return new TextWindowState(currentText.toString());
+    }
+
+    public void restore(TextWindowState save) {
+        currentText = new StringBuilder(save.getText());
+        cursorPosition = atTextEnd();
+    }
+
+    private Coordinates atTextEnd() {
+        String[] lines = currentText.toString().split("\n");
+        return new Coordinates(lines[lines.length - 1].length(), lines.length);
+    }
+}
diff --git a/patterns/design-patterns-2/src/main/java/com/baeldung/memento/TextWindowState.java b/patterns/design-patterns-2/src/main/java/com/baeldung/memento/TextWindowState.java
new file mode 100644
index 0000000000..10015a84d1
--- /dev/null
+++ b/patterns/design-patterns-2/src/main/java/com/baeldung/memento/TextWindowState.java
@@ -0,0 +1,14 @@
+package com.baeldung.memento;
+
+public class TextWindowState {
+
+    private String text;
+
+    public TextWindowState(String text) {
+        this.text = text;
+    }
+
+    public String getText() {
+        return text;
+    }
+}