add choreogr

saga/src/main/java/com/iluwatar/saga/choreography/Chapter.java

@@ -22,13 +22,20 @@
  */
 package com.iluwatar.saga.choreography;
 
-import com.iluwatar.saga.orchestration.ChapterResult;
 
 /**
  * Chapter is an interface representing a contract for an external service.
- * @param <K> is type for passing params
- */
-public interface Chapter<K> {
+ * In that case, a service needs to make a decision what to do further
+ * hence the server needs to get all context representing {@link Saga}
+ * */
+public interface Chapter {
+
+    /**
+     * In that case, every method is responsible to make a decision on what to do then
+     * @param saga incoming saga
+     * @return saga result
+     */
+    Saga execute(Saga saga);
 
     /**
      * @return service name.
@@ -37,17 +44,17 @@ public interface Chapter<K> {
 
     /**
      * The operation executed in general case.
-     * @param value incoming value
-     * @return result {@link ChapterResult}
+     * @param saga incoming saga
+     * @return result {@link Saga}
      */
-    ChapterResult<K> process(K value);
+    Saga process(Saga saga);
 
     /**
      * The operation executed in rollback case.
-     * @param value incoming value
-     * @return result {@link ChapterResult}
+     * @param saga incoming saga
+     * @return result {@link Saga}
      */
-    ChapterResult<K> rollback(K value);
+    Saga rollback(Saga saga);
 
 
 }

saga/src/main/java/com/iluwatar/saga/choreography/FlyBookingService.java

@@ -0,0 +1,38 @@
+/*
+ * 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.
+ */
+package com.iluwatar.saga.choreography;
+
+
+/**
+ * Class representing a service to book a fly
+ */
+public class FlyBookingService extends Service {
+    public FlyBookingService(ServiceDiscoveryService service) {
+        super(service);
+    }
+
+    @Override
+    public String getName() {
+        return "booking a Fly";
+    }
+}

saga/src/main/java/com/iluwatar/saga/choreography/HotelBookingService.java

@@ -0,0 +1,40 @@
+/*
+ * 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.
+ */
+package com.iluwatar.saga.choreography;
+
+
+/**
+ * Class representing a service to book a hotel
+ */
+public class HotelBookingService extends Service {
+    public HotelBookingService(ServiceDiscoveryService service) {
+        super(service);
+    }
+
+    @Override
+    public String getName() {
+        return "booking a Hotel";
+    }
+
+
+   }

saga/src/main/java/com/iluwatar/saga/choreography/OrderService.java

@@ -0,0 +1,39 @@
+/*
+ * 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.
+ */
+package com.iluwatar.saga.choreography;
+
+
+/**
+ * Class representing a service to init a new order.
+ */
+public class OrderService extends Service{
+
+    public OrderService(ServiceDiscoveryService service) {
+        super(service);
+    }
+
+    @Override
+    public String getName() {
+        return "init an order";
+    }
+}

saga/src/main/java/com/iluwatar/saga/choreography/Saga.java

@@ -22,13 +22,138 @@
  */
 package com.iluwatar.saga.choreography;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
 /**
  * Saga representation.
  * Saga consists of chapters.
  * Every Chapter is executed a certain service.
  */
 public class Saga {
 
+    private List<Chapter> chapters;
+    private int pos;
+    private boolean forward;
+    private boolean finished;
+
+
+    public static Saga create() {
+        return new Saga();
+    }
+    public SagaResult getResult() {
+        return !finished ?
+                SagaResult.PROGRESS :
+                forward ?
+                        SagaResult.FINISHED :
+                        SagaResult.ROLLBACKED;
+    }
+    public Saga chapter(String name) {
+        this.chapters.add(new Chapter(name));
+        return this;
+    }
+    public Saga setInValue(Object value){
+        if(chapters.isEmpty()){
+            return this;
+        }
+        chapters.get(chapters.size()-1).setInValue(value);
+        return this;
+    }
+    public Object getCurrentValue(){
+        return chapters.get(pos).getInValue();
+    }
+    public void setCurrentValue(Object value){
+        chapters.get(pos).setInValue(value);
+    }
+    public void setCurrentStatus(ChapterResult result){
+        chapters.get(pos).setResult(result);
+    }
+
+    void setFinished(boolean finished) {
+        this.finished = finished;
+    }
+    boolean isForward() {
+        return forward;
+    }
+    int forward() {
+        return ++pos;
+    }
+
+    int back() {
+        this.forward = false;
+        return --pos;
+    }
+
+
+    public Saga() {
+        this.chapters = new ArrayList<>();
+        this.pos = 0;
+        this.forward = true;
+        this.finished = false;
+    }
+
+    Chapter getCurrent() {
+        return chapters.get(pos);
+    }
+
+
+    boolean isPresent() {
+        return pos >= 0 && pos < chapters.size();
+    }
+    boolean isCurrentSuccess(){
+        return chapters.get(pos).isSuccess();
+    }
+
+    /***
+     * Class presents a chapter status and incoming parameters(incoming parameter transforms to outcoming parameter)
+     */
+    public static class Chapter {
+        private String name;
+        private ChapterResult result;
+        private Object inValue;
+
+
+        public Chapter(String name) {
+            this.name = name;
+            this.result = ChapterResult.INIT;
+        }
+
+        public Object getInValue() {
+            return inValue;
+        }
+
+        public void setInValue(Object object) {
+            this.inValue = object;
+        }
+
+        public String getName() {
+            return name;
+        }
+        public void setResult(ChapterResult result){
+            this.result = result;
+        }
+
+        public boolean isSuccess(){
+            return result == ChapterResult.SUCCESS;
+        }
+    }
+
+
+    public enum ChapterResult {
+        INIT, SUCCESS, ROLLBACK
+    }
 
+    public enum SagaResult {
+        PROGRESS, FINISHED, ROLLBACKED
+    }
 
+    @Override
+    public String toString() {
+        return "Saga{" +
+                "chapters=" + Arrays.toString(chapters.toArray()) +
+                ", pos=" + pos +
+                ", forward=" + forward +
+                '}';
+    }
 }

saga/src/main/java/com/iluwatar/saga/choreography/SagaApplication.java

@@ -0,0 +1,77 @@
+/*
+ * 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.
+ */
+package com.iluwatar.saga.choreography;
+
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * 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 executed
+ * in a distributed environment
+ * <p>
+ * 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.
+ * <p>
+ * In this approach, there are no mediators or orchestrators services.
+ * All chapters are handled and moved by services manually.
+ * <p>
+ * The major difference with choreography saga is an ability to handle crashed services
+ * (otherwise in choreography services very hard to prevent a saga if one of them has been crashed)
+ *
+ * @see com.iluwatar.saga.choreography.Saga
+ * @see Service
+ */
+public class SagaApplication {
+    private static final Logger logger = LoggerFactory.getLogger(SagaApplication.class);
+
+    public static void main(String[] args) {
+        ServiceDiscoveryService sd = serviceDiscovery();
+        Chapter service = sd.findAny();
+        Saga goodOrderSaga = service.execute(newSaga("good_order"));
+        Saga badOrderSaga = service.execute(newSaga("bad_order"));
+        logger.info("orders: goodOrder is {}, badOrder is {}",
+                goodOrderSaga.getResult(), badOrderSaga.getResult());
+
+    }
+
+
+    private static Saga newSaga(Object value) {
+        return Saga
+                .create()
+                .chapter("init an order").setInValue(value)
+                .chapter("booking a Fly")
+                .chapter("booking a Hotel")
+                .chapter("withdrawing Money");
+    }
+
+    private static ServiceDiscoveryService serviceDiscovery() {
+        ServiceDiscoveryService sd = new ServiceDiscoveryService();
+        return sd
+                .discover(new OrderService(sd))
+                .discover(new FlyBookingService(sd))
+                .discover(new HotelBookingService(sd))
+                .discover(new WithdrawMoneyService(sd));
+    }
+}