Preliminary support for Spring Data persist

- Add new repository model for storing StateMachineContext
  via a new StateMachineRepository.
- New StateMachineRuntimePersister interface to abstract needed
  functionality to do a runtime machine persistence.
- As runtime persistence, as of now, is done via interceptors, define
  JpaRepositoryStateMachinePersist and JpaPersistingStateMachineInterceptor
  to define StateMachineRuntimePersister logic.
- Add new datajpapersist sample demonstrating new concepts.
- Keep tests related to jpa as there's not redis/mongo integration
  implemented in this first iteration.
- As this is going to be WIP until features around this issues
  are completed, docs, etc are not yet added. Also, interfaces and impls
  are subject to change during a process.
- Relates to #423
- Relates to #426
- Relates to #427

spring-statemachine-data/src/main/java/org/springframework/statemachine/data/RepositoryStateMachine.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.statemachine.data;
+
+/**
+ * Generic base class representing state machine entity.
+ *
+ * @author Janne Valkealahti
+ *
+ */
+public abstract class RepositoryStateMachine extends BaseRepositoryEntity {
+
+	/**
+	 * Gets the machine id.
+	 *
+	 * @return the machine id
+	 */
+	public abstract String getMachineId();
+
+	/**
+	 * Gets the state.
+	 *
+	 * @return the state
+	 */
+	public abstract String getState();
+
+	/**
+	 * Gets the state machine context.
+	 *
+	 * @return the state machine context
+	 */
+	public abstract byte[] getStateMachineContext();
+}

spring-statemachine-data/src/main/java/org/springframework/statemachine/data/RepositoryStateMachineModelFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 the original author or authors.
+ * Copyright 2016-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -30,7 +30,6 @@ import org.springframework.statemachine.action.Action;
 import org.springframework.statemachine.action.SpelExpressionAction;
 import org.springframework.statemachine.config.model.AbstractStateMachineModelFactory;
 import org.springframework.statemachine.config.model.ChoiceData;
-import org.springframework.statemachine.config.model.ConfigurationData;
 import org.springframework.statemachine.config.model.DefaultStateMachineModel;
 import org.springframework.statemachine.config.model.EntryData;
 import org.springframework.statemachine.config.model.ExitData;
@@ -80,8 +79,6 @@ public class RepositoryStateMachineModelFactory extends AbstractStateMachineMode
 
 	@Override
 	public StateMachineModel<String, String> build(String machineId) {
-		ConfigurationData<String, String> configurationData = new ConfigurationData<>();
-
 		Collection<StateData<String, String>> stateDatas = new ArrayList<>();
 		for (RepositoryState s : stateRepository.findByMachineId(machineId == null ? "" : machineId)) {
 
@@ -284,8 +281,7 @@ public class RepositoryStateMachineModelFactory extends AbstractStateMachineMode
 		TransitionsData<String, String> transitionsData = new TransitionsData<>(transitionData, choicesCopy, junctionsCopy, forks, joins,
 				entrys, exits, historys);
 
-		StateMachineModel<String, String> stateMachineModel = new DefaultStateMachineModel<>(configurationData, statesData, transitionsData);
-		return stateMachineModel;
+		return new DefaultStateMachineModel<>(null, statesData, transitionsData);
 	}
 
 	private Guard<String, String> resolveGuard(RepositoryTransition t) {

spring-statemachine-data/src/main/java/org/springframework/statemachine/data/RepositoryStateMachinePersist.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.statemachine.data;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.springframework.statemachine.StateMachineContext;
+import org.springframework.statemachine.StateMachinePersist;
+import org.springframework.statemachine.kryo.KryoSerialisationService;
+
+/**
+ * Base implementation of a {@link StateMachinePersist} using Spring Data Repositories.
+ *
+ * @author Janne Valkealahti
+ *
+ * @param <S> the type of state
+ * @param <E> the type of event
+ * @param <M> the type of entity
+ */
+public abstract class RepositoryStateMachinePersist<M extends RepositoryStateMachine, S, E> implements StateMachinePersist<S, E, Object> {
+
+	private final Log log = LogFactory.getLog(RepositoryStateMachinePersist.class);
+	private final KryoSerialisationService serialisationService = new KryoSerialisationService();
+
+	@Override
+	public void write(StateMachineContext<S, E> context, Object contextObj) throws Exception {
+		if (log.isDebugEnabled()) {
+			log.debug("Persisting context " + context + " using contextObj " + contextObj);
+		}
+		M build = build(context, serialisationService.serializeStateMachineContext(context));
+		getRepository().save(build);
+	}
+
+	@Override
+	public StateMachineContext<S, E> read(Object contextObj) throws Exception {
+		M repositoryStateMachine = getRepository().findOne(contextObj.toString());
+		if (repositoryStateMachine != null) {
+			return serialisationService.deserializeStateMachineContext(repositoryStateMachine.getStateMachineContext());
+		}
+		return null;
+	}
+
+	/**
+	 * Gets the repository.
+	 *
+	 * @return the repository
+	 */
+	protected abstract StateMachineRepository<M> getRepository();
+
+	/**
+	 * Builds the generic {@link RepositoryStateMachine} entity.
+	 *
+	 * @param context the context
+	 * @param serialisedContext the serialised context
+	 * @return the repository state machine entity
+	 */
+	protected abstract M build(StateMachineContext<S, E> context, byte[] serialisedContext);
+}

spring-statemachine-data/src/main/java/org/springframework/statemachine/data/StateMachineRepository.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.statemachine.data;
+
+import org.springframework.data.repository.CrudRepository;
+import org.springframework.data.repository.NoRepositoryBean;
+import org.springframework.data.repository.Repository;
+
+/**
+ * Generic {@link Repository} interface for states machines.
+ *
+ * @author Janne Valkealahti
+ *
+ */
+@NoRepositoryBean
+public interface StateMachineRepository<M extends RepositoryStateMachine> extends CrudRepository<M, String> {
+}