From ec0ec38b0630cf1f1b8879b16ea988fb42b7c356 Mon Sep 17 00:00:00 2001
From: soufiane-cheouati <46105138+soufiane-cheouati@users.noreply.github.com>
Date: Fri, 1 Feb 2019 20:16:40 +0000
Subject: [PATCH 1/4] Adding marker interfaces files

---
 .../baeldung/markerinterface/Deletable.java   |  5 +++++
 .../markerinterface/DeletableShape.java       |  7 ++++++
 .../baeldung/markerinterface/Rectangle.java   | 22 +++++++++++++++++++
 .../baeldung/markerinterface/ShapeDao.java    | 14 ++++++++++++
 4 files changed, 48 insertions(+)
 create mode 100644 core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Deletable.java
 create mode 100644 core-java-lang-oop/src/main/java/com/baeldung/markerinterface/DeletableShape.java
 create mode 100644 core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Rectangle.java
 create mode 100644 core-java-lang-oop/src/main/java/com/baeldung/markerinterface/ShapeDao.java

diff --git a/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Deletable.java b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Deletable.java
new file mode 100644
index 0000000000..d40d81b1d4
--- /dev/null
+++ b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Deletable.java
@@ -0,0 +1,5 @@
+package com.baeldung.markerinterface;
+
+public interface Deletable extends DeletableShape {
+
+}
diff --git a/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/DeletableShape.java b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/DeletableShape.java
new file mode 100644
index 0000000000..d5ae52c9f2
--- /dev/null
+++ b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/DeletableShape.java
@@ -0,0 +1,7 @@
+package com.baeldung.markerinterface;
+
+public interface DeletableShape {
+    double getArea();
+
+    double getCircumference();
+}
\ No newline at end of file
diff --git a/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Rectangle.java b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Rectangle.java
new file mode 100644
index 0000000000..f8ea987c6f
--- /dev/null
+++ b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Rectangle.java
@@ -0,0 +1,22 @@
+package com.baeldung.markerinterface;
+
+public class Rectangle implements Deletable {
+
+    private double width;
+    private double height;
+
+    public Rectangle(double width, double height) {
+        this.width = width;
+        this.height = height;
+    }
+
+    @Override
+    public double getArea() {
+        return width * height;
+    }
+
+    @Override
+    public double getCircumference() {
+        return 2 * (width + height);
+    }
+}
diff --git a/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/ShapeDao.java b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/ShapeDao.java
new file mode 100644
index 0000000000..49a389bd46
--- /dev/null
+++ b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/ShapeDao.java
@@ -0,0 +1,14 @@
+package com.baeldung.markerinterface;
+
+public class ShapeDao {
+
+    public boolean delete(Object object) {
+        if (!(object instanceof Deletable)) {
+            return false;
+        }
+        // Calling the code that deletes the entity from the database
+
+        return true;
+    }
+
+}

From f76d6bd66849a0ea148ea3cacb8835b9e64fcd9b Mon Sep 17 00:00:00 2001
From: soufiane-cheouati <46105138+soufiane-cheouati@users.noreply.github.com>
Date: Fri, 1 Feb 2019 20:18:24 +0000
Subject: [PATCH 2/4] Adding marker interfaces UT

---
 .../MarkerInterfaceUnitTest.java              | 26 +++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 core-java-lang-oop/src/test/java/com/baeldung/markerinterface/MarkerInterfaceUnitTest.java

diff --git a/core-java-lang-oop/src/test/java/com/baeldung/markerinterface/MarkerInterfaceUnitTest.java b/core-java-lang-oop/src/test/java/com/baeldung/markerinterface/MarkerInterfaceUnitTest.java
new file mode 100644
index 0000000000..70d32ba253
--- /dev/null
+++ b/core-java-lang-oop/src/test/java/com/baeldung/markerinterface/MarkerInterfaceUnitTest.java
@@ -0,0 +1,26 @@
+package com.baeldung.markerinterface;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class MarkerInterfaceUnitTest {
+
+    @Test
+    public void givenDeletableObjectThenTrueReturned() {
+        ShapeDao shapeDao = new ShapeDao();
+        Object rectangle = new Rectangle(2, 3);
+
+        boolean result = shapeDao.delete(rectangle);
+        assertEquals(true, result);
+    }
+    
+    @Test
+    public void givenNonDeletableObjectThenFalseReturned() {
+        ShapeDao shapeDao = new ShapeDao();
+        Object object = new Object();
+
+        boolean result = shapeDao.delete(object);
+        assertEquals(false, result);
+    }
+}

From 565f69ecf30a83ca13c7c1fa2c1e47f6c12a7b16 Mon Sep 17 00:00:00 2001
From: soufiane-cheouati <46105138+soufiane-cheouati@users.noreply.github.com>
Date: Sun, 3 Feb 2019 20:44:04 +0000
Subject: [PATCH 3/4] Add files via upload

---
 .../java/com/baeldung/markerinterface/DeletableShape.java   | 6 ++----
 .../main/java/com/baeldung/markerinterface/Rectangle.java   | 2 +-
 .../src/main/java/com/baeldung/markerinterface/Shape.java   | 6 ++++++
 .../main/java/com/baeldung/markerinterface/ShapeDao.java    | 2 +-
 4 files changed, 10 insertions(+), 6 deletions(-)
 create mode 100644 core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Shape.java

diff --git a/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/DeletableShape.java b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/DeletableShape.java
index d5ae52c9f2..7674407da8 100644
--- a/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/DeletableShape.java
+++ b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/DeletableShape.java
@@ -1,7 +1,5 @@
 package com.baeldung.markerinterface;
 
-public interface DeletableShape {
-    double getArea();
+public interface DeletableShape extends Shape {
 
-    double getCircumference();
-}
\ No newline at end of file
+}
diff --git a/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Rectangle.java b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Rectangle.java
index f8ea987c6f..d64ffad0a2 100644
--- a/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Rectangle.java
+++ b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Rectangle.java
@@ -1,6 +1,6 @@
 package com.baeldung.markerinterface;
 
-public class Rectangle implements Deletable {
+public class Rectangle implements DeletableShape {
 
     private double width;
     private double height;
diff --git a/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Shape.java b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Shape.java
new file mode 100644
index 0000000000..2e53aefc03
--- /dev/null
+++ b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Shape.java
@@ -0,0 +1,6 @@
+package com.baeldung.markerinterface;
+
+public interface Shape {
+    double getArea();
+    double getCircumference();
+}
\ No newline at end of file
diff --git a/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/ShapeDao.java b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/ShapeDao.java
index 49a389bd46..bc988a793d 100644
--- a/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/ShapeDao.java
+++ b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/ShapeDao.java
@@ -3,7 +3,7 @@ package com.baeldung.markerinterface;
 public class ShapeDao {
 
     public boolean delete(Object object) {
-        if (!(object instanceof Deletable)) {
+        if (!(object instanceof DeletableShape)) {
             return false;
         }
         // Calling the code that deletes the entity from the database

From afb46cd8cf3483b76280db355bef38507425dbdb Mon Sep 17 00:00:00 2001
From: soufiane-cheouati <46105138+soufiane-cheouati@users.noreply.github.com>
Date: Sun, 3 Feb 2019 20:56:53 +0000
Subject: [PATCH 4/4] Delete Deletable.java

---
 .../main/java/com/baeldung/markerinterface/Deletable.java    | 5 -----
 1 file changed, 5 deletions(-)
 delete mode 100644 core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Deletable.java

diff --git a/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Deletable.java b/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Deletable.java
deleted file mode 100644
index d40d81b1d4..0000000000
--- a/core-java-lang-oop/src/main/java/com/baeldung/markerinterface/Deletable.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package com.baeldung.markerinterface;
-
-public interface Deletable extends DeletableShape {
-
-}