add saga init dsc

pom.xml

@@ -183,6 +183,8 @@
         <module>data-locality</module>
         <module>subclass-sandbox</module>
         <module>circuit-breaker</module>
+        <module>role-object</module>
+		<module>saga</module>
     </modules>
 
     <repositories>

saga/README.md

@@ -0,0 +1,45 @@
+---
+layout: pattern
+title: Saga
+folder: Communication
+permalink: /patterns/saga/
+categories: Behavioral
+tags:
+ - Java
+ - Difficulty-Expert
+ - Idiom
+ - Distributed communication
+---
+
+## Also known as
+This pattern has a similar goal with two-phase commit (XA transaction)
+
+## Intent
+This pattern is used in distributed services to perform a group of operations atomically.
+This is an analog of transaction in a database but in terms of microservices architecture this is performed in a distributed environment
+
+## Explanation
+A saga is a sequence of local transactions in a certain context. If one transaction fails for some reason, 
+the saga executes compensating transactions(rollbacks) to undo the impact of the preceding transactions.
+There are two types of Saga:
+
+- Choreography-Based Saga. 
+In this approach, there is no central orchestrator. 
+Each service participating in the Saga performs their transaction and publish events. 
+The other services act upon those events and perform their transactions. 
+Also, they may or not publish other events based on the situation.
+
+- Orchestration-Based Saga
+In this approach, there is a Saga orchestrator that manages all the transactions and directs 
+the participant services to execute local transactions based on events. 
+This orchestrator can also be though of as a Saga Manager.
+
+## Applicability
+Use the Saga pattern, if:
+- you need to perform a group of operations related to different microservices atomically
+- you need to rollback changes in different places in case of failure one of the operation
+- you need to take care of data consistency in different places including different databases
+- you can not use 2PC(two phase commit)
+
+## Credits
+- [pattern description](https://microservices.io/patterns/data/saga.html)

saga/pom.xml

@@ -0,0 +1,44 @@
+<?xml version="1.0"?>
+<!--
+
+    The MIT License
+    Copyright © 2014-2019 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.22.0-SNAPSHOT</version>
+  </parent>
+
+  <artifactId>saga</artifactId>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+</project>

stirring-clicker/pom.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>ie.home.besok</groupId>
+    <artifactId>move-clicker</artifactId>
+    <version>1.0</version>
+    <properties>
+        <maven.compiler.target>1.8</maven.compiler.target>
+        <maven.compiler.source>1.8</maven.compiler.source>
+    </properties>
+
+<dependencies>
+    <dependency>
+        <groupId>org.projectlombok</groupId>
+        <artifactId>lombok</artifactId>
+        <version>1.18.10</version>
+    </dependency>
+
+    <dependency>
+        <groupId>junit</groupId>
+        <artifactId>junit</artifactId>
+        <version>4.12</version>
+    </dependency>
+</dependencies>
+</project>

stirring-clicker/src/main/java/ie/home/besok/stirrings/Application.java

@@ -0,0 +1,15 @@
+package ie.home.besok.stirrings;
+
+import java.awt.*;
+import java.io.IOException;
+
+public class Application {
+    public static void main(String[] args) throws IOException {
+        FileStorage storage = new FileStorage();
+
+        EventQueue.invokeLater(() -> {
+            Gui gui = new Gui(storage);
+            gui.setVisible(true);
+        });
+    }
+}

stirring-clicker/src/main/java/ie/home/besok/stirrings/Counter.java

@@ -0,0 +1,14 @@
+package ie.home.besok.stirrings;
+
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+public class Counter {
+    public Map<LocalDate,Long> count(List<String> dates){
+        return null;
+    }
+}

stirring-clicker/src/main/java/ie/home/besok/stirrings/FileStorage.java

@@ -0,0 +1,37 @@
+package ie.home.besok.stirrings;
+
+import lombok.extern.slf4j.Slf4j;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardOpenOption;
+import java.time.LocalDateTime;
+import java.util.List;
+
+public class FileStorage {
+
+    private Path file;
+
+    public FileStorage() throws IOException {
+        this.file = Paths.get("data.log");
+        if(!Files.exists(file)){
+                Files.createFile(file);
+        }
+    }
+
+    public void plus() {
+        String line = LocalDateTime.now().toString()+System.lineSeparator();
+        try {
+            Files.write(file, line.getBytes(), StandardOpenOption.APPEND);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    public List<String> get() throws IOException {
+        return Files.readAllLines(file);
+    }
+
+}

stirring-clicker/src/main/java/ie/home/besok/stirrings/Gui.java

@@ -0,0 +1,73 @@
+package ie.home.besok.stirrings;
+
+import javax.imageio.ImageIO;
+import javax.swing.*;
+import java.awt.*;
+import java.io.IOException;
+import java.net.URL;
+
+public class Gui extends JFrame {
+
+    private FileStorage storage;
+
+    public Gui(FileStorage storage) {
+        this.storage = storage;
+        try {
+            createUI(storage);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private void createUI(FileStorage storage) throws IOException {
+        setTitle("Stirring counter");
+        setSize(300, 300);
+        setLocationRelativeTo(null);
+
+
+        JButton button = createButton(storage);
+        JButton graphick = new JButton();
+        graphick.setIcon(getIcon("3.jpg"));
+
+
+        Container pane = getContentPane();
+        GroupLayout gl = new GroupLayout(pane);
+        pane.setLayout(gl);
+
+        gl.setAutoCreateContainerGaps(true);
+
+        gl.setHorizontalGroup(
+                gl.createSequentialGroup().addComponent(button).addComponent(graphick)
+        );
+
+        gl.setVerticalGroup(gl.createSequentialGroup().addComponent(button).addComponent(graphick));
+
+
+        button.addActionListener((event) -> {
+            storage.plus();
+            try {
+                JOptionPane.showMessageDialog(null,"","",JOptionPane.INFORMATION_MESSAGE, getIcon("2.jpg"));
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        });
+
+        setDefaultCloseOperation(EXIT_ON_CLOSE);
+    }
+
+    private JButton createButton(FileStorage storage) throws IOException {
+        ImageIcon babyIcon = getIcon("1.png");
+
+        JButton button = new JButton();
+
+        button.setIcon(babyIcon);
+        return button;
+    }
+
+    private ImageIcon getIcon(String name) throws IOException {
+        URL file = this.getClass().getClassLoader().getResource(name);
+        return new ImageIcon(ImageIO.read(file));
+    }
+
+
+}

stirring-clicker/src/test/java/ie/home/besok/stirrings/FileStorageTest.java

@@ -0,0 +1,25 @@
+package ie.home.besok.stirrings;
+
+import org.junit.Test;
+
+import java.io.IOException;
+import java.util.List;
+
+import static org.junit.Assert.*;
+
+public class FileStorageTest {
+
+    @Test
+    public void fsTest() throws IOException {
+        FileStorage fs = new FileStorage();
+        List<String> arrs = fs.get();
+        int oldSize = arrs.size();
+        fs.plus();
+        fs.plus();
+        fs.plus();
+        fs.plus();
+        arrs = fs.get();
+        int newSize = arrs.size();
+        assertEquals(4, newSize - oldSize);
+    }
+}