Add template design pattern with test case (#53)

Author: mperor

DesignPatterns/README.md

@@ -11,8 +11,9 @@ with practical examples and best practices for using design patterns to create r
 
 - [Command](src/main/java/pl/mperor/lab/java/design/pattern/behavioral/command) 📝
 - [Execute Around Method (EAM)](src/main/java/pl/mperor/lab/java/design/pattern/behavioral/eam) ⭕
-- [Strategy](src/main/java/pl/mperor/lab/java/design/pattern/behavioral/strategy) 🎯
 - [Observer](src/main/java/pl/mperor/lab/java/design/pattern/behavioral/observer) 👀
+- [Strategy](src/main/java/pl/mperor/lab/java/design/pattern/behavioral/strategy) 🎯
+- [Template Method](src/main/java/pl/mperor/lab/java/design/pattern/behavioral/template/method) 📋
 
 ### Creational Design Patterns 🏭
 

DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/behavioral/template/method/BackupProcess.java

@@ -0,0 +1,26 @@
+package pl.mperor.lab.java.design.pattern.behavioral.template.method;
+
+public abstract class BackupProcess {
+
+    public final void execute() {
+        if (!canExecuteBackup()) {
+            System.out.println("⛔ Backup not possible. Process terminated.");
+            return;
+        }
+        performBackup();
+        verifyBackup();
+        cleanup();
+    }
+
+    protected boolean canExecuteBackup() {
+        return true;
+    }
+
+    protected abstract void performBackup();
+
+    protected abstract void verifyBackup();
+
+    protected void cleanup() {
+        System.out.println("🧹 Deleting old backup files...");
+    }
+}

DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/behavioral/template/method/DatabaseBackup.java

@@ -0,0 +1,24 @@
+package pl.mperor.lab.java.design.pattern.behavioral.template.method;
+
+public class DatabaseBackup extends BackupProcess {
+
+    DatabaseBackup() {
+        System.out.println("===== Database Backup =====");
+    }
+
+    @Override
+    protected boolean canExecuteBackup() {
+        System.out.println("🗄️ Checking database connection...");
+        return true;
+    }
+
+    @Override
+    protected void performBackup() {
+        System.out.println("💾 Dumping database to SQL file...");
+    }
+
+    @Override
+    protected void verifyBackup() {
+        System.out.println("✅ Checking database dump integrity...");
+    }
+}

DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/behavioral/template/method/LocalFileBackup.java

@@ -0,0 +1,24 @@
+package pl.mperor.lab.java.design.pattern.behavioral.template.method;
+
+public class LocalFileBackup extends BackupProcess {
+
+    LocalFileBackup() {
+        System.out.println("===== File Backup =====");
+    }
+
+    @Override
+    protected boolean canExecuteBackup() {
+        System.out.println("🔍 Checking disk space for backup...");
+        return true;
+    }
+
+    @Override
+    protected void performBackup() {
+        System.out.println("📂 Copying files to backup directory...");
+    }
+
+    @Override
+    protected void verifyBackup() {
+        System.out.println("🔢 Comparing checksums of original and copied files...");
+    }
+}

DesignPatterns/src/test/java/pl/mperor/lab/java/design/pattern/behavioral/template/method/BackupProcessTemplateTest.java

@@ -0,0 +1,33 @@
+package pl.mperor.lab.java.design.pattern.behavioral.template.method;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import pl.mperor.lab.common.TestUtils;
+
+public class BackupProcessTemplateTest {
+
+    @Test
+    public void shouldAllowToExecuteBackupProcessForDifferentDataSources() {
+        var out = TestUtils.setTempSystemOut();
+        new DatabaseBackup().execute();
+        Assertions.assertLinesMatch("""
+                ===== Database Backup =====
+                🗄️ Checking database connection...
+                💾 Dumping database to SQL file...
+                ✅ Checking database dump integrity...
+                🧹 Deleting old backup files...
+                """.lines(), out.lines().stream());
+
+        out = TestUtils.setTempSystemOut();
+        new LocalFileBackup().execute();
+        Assertions.assertLinesMatch("""
+                ===== File Backup =====
+                🔍 Checking disk space for backup...
+                📂 Copying files to backup directory...
+                🔢 Comparing checksums of original and copied files...
+                🧹 Deleting old backup files...
+                """.lines(), out.lines().stream());
+
+        TestUtils.resetSystemOut();
+    }
+}