Hibernate and H2

Author: eliovir

pom.xml

@@ -23,6 +23,7 @@ Now, we add GWT (gwt-servlet and gwt-user artifacts) and Log4J  to our project.
         <gwt.version>2.7.0</gwt.version>
         <mybatis.version>3.2.1</mybatis.version>
         <mybatis-spring.version>1.2.0</mybatis-spring.version>
+        <hibernate.version>4.3.7.Final</hibernate.version>
         <!--
         <mysql-connector-java.version>5.1.18</mysql-connector-java.version>
         -->
@@ -31,7 +32,11 @@ Now, we add GWT (gwt-servlet and gwt-user artifacts) and Log4J  to our project.
         <postgresql-connector-java.version>9.3-1102-jdbc3</postgresql-connector-java.version>
         -->
         <!-- http://mvnrepository.com/artifact/org.xerial/sqlite-jdbc -->
+        <!--
         <sqlite-connector-java.version>3.8.7</sqlite-connector-java.version>
+        -->
+        <!-- http://mvnrepository.com/artifact/com.h2database/h2 -->
+        <h2.version>1.4.184</h2.version>
         <!-- Note: GWT needs at least java 1.6 -->
         <maven.compiler.source>1.7</maven.compiler.source>
         <maven.compiler.target>1.7</maven.compiler.target>
@@ -50,6 +55,11 @@ Now, we add GWT (gwt-servlet and gwt-user artifacts) and Log4J  to our project.
             <artifactId>spring-jdbc</artifactId>
             <version>${spring.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-orm</artifactId>
+            <version>${spring.version}</version>
+        </dependency>
 
         <!-- GWT -->
         <dependency>
@@ -92,6 +102,12 @@ Now, we add GWT (gwt-servlet and gwt-user artifacts) and Log4J  to our project.
             <artifactId>mybatis-spring</artifactId>
             <version>${mybatis-spring.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.hibernate</groupId>
+            <artifactId>hibernate-core</artifactId>
+            <version>4.3.7.Final</version>
+            <type>jar</type>
+        </dependency>
         <!--
         <dependency>
             <groupId>mysql</groupId>
@@ -103,12 +119,17 @@ Now, we add GWT (gwt-servlet and gwt-user artifacts) and Log4J  to our project.
             <artifactId>postgresql</artifactId>
             <version>${postgresql-connector-java.version}</version>
         </dependency>
-        -->
         <dependency>
             <groupId>org.xerial</groupId>
             <artifactId>sqlite-jdbc</artifactId>
             <version>${sqlite-connector-java.version}</version>
         </dependency>
+        -->
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <version>${h2.version}</version>
+        </dependency>        
     </dependencies>
 
     <build>

src/main/java/com/hellogwt/client/GreetingService.java

@@ -36,4 +36,6 @@ public interface GreetingService extends RemoteService {
     List<Greeting> getGreetings();
 
     String greet(String name);
+    
+    String persistenceClassName();
 }

src/main/java/com/hellogwt/client/GreetingServiceAsync.java

@@ -32,4 +32,6 @@ public interface GreetingServiceAsync {
     void getGreetings(AsyncCallback<List<Greeting>> async);
 
     void greet(String name, AsyncCallback<String> callback);
+
+    void persistenceClassName(AsyncCallback<String> callback);
 }

src/main/java/com/hellogwt/client/HelloGWTWidget.java

@@ -91,9 +91,21 @@ public void onSuccess(Void result) {
     FlexTable greetingsFlexTable;
     @UiField
     SpanElement statusMessage;
+    @UiField
+    SpanElement persistenceClassName;
 
     public HelloGWTWidget() {
         initWidget(uiBinder.createAndBindUi(this));
+        greetingService.persistenceClassName(new AsyncCallback<String>() {
+            @Override
+            public void onFailure(Throwable caught) {
+                statusMessage.setInnerHTML(clientMsg.error() + caught.getLocalizedMessage()); 
+            }
+            @Override
+            public void onSuccess(String result) {
+                persistenceClassName.setInnerHTML(result);
+            }
+        });
         refreshGreetingsTable();
     }
 

src/main/java/com/hellogwt/client/HelloGWTWidget.ui.xml

@@ -74,6 +74,7 @@ removing the package prefix "com.hellogwt.client.".
                     <span ui:field="statusMessage">
                         <ui:msg key="defaultStatusMessage" meaning="Default status message.">Application is loaded.</ui:msg>
                     </span>
+                    <span ui:field="persistenceClassName"></span>
                     <p>
                         <a href="?locale=fr">français</a>,
                         <a href="?locale=en">English</a>

src/main/java/com/hellogwt/server/GreetingServiceImpl.java

@@ -16,25 +16,32 @@
 package com.hellogwt.server;
 
 import com.hellogwt.client.GreetingService;
-import com.hellogwt.server.persistence.GreetingMapper;
+import com.hellogwt.server.persistence.GreetingPersistence;
 import com.hellogwt.shared.domain.Greeting;
 import java.util.List;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
 /**
  * A class that implements GreetingService interface in com.hellogwt.server
- * package. Don't forget to annotate it with @Service. Class GreetingServiceImpl
+ * package.
+ * 
+ * Don't forget to annotate it with @Service. Class GreetingServiceImpl
  * implements method greet(). In our case the method takes one String as an
  * argument, builds another String and returns it. Implements all declared CRUD
  * methods in service GreetingServiceImpl using created mapper.
+ * 
+ * @Transactional annotation provided by Spring:
+ * when a method is annotated by this annotation, Spring will inject
+ * transaction support code into the method - thus we don’t have two write any
+ * code to handle transaction explicitly.
  */
 @Service("greetingService")
 public class GreetingServiceImpl implements GreetingService {
 
     @Autowired
-    private GreetingMapper greetingMapper;
-    
+    private GreetingPersistence greetingMapper;
+
     @Override
     public Greeting getGreeting(String text) {
         return greetingMapper.getGreeting(text);
@@ -64,4 +71,9 @@ public List<Greeting> getGreetings() {
     public String greet(String name) {
         return "Hello, " + name + "!";
     }
+    
+    @Override
+    public String persistenceClassName() {
+        return (greetingMapper instanceof com.hellogwt.server.persistence.GreetingMapper ? "MyBatis": "Hibernate");
+    }
 }

src/main/java/com/hellogwt/server/persistence/GreetingDAO.java

@@ -0,0 +1,94 @@
+/**
+ * Hibernate class to handle Greeting.
+ *
+ * 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 com.hellogwt.server.persistence;
+
+import org.springframework.stereotype.Repository;
+import com.hellogwt.shared.domain.Greeting;
+import java.util.List;
+import org.hibernate.Criteria;
+import org.hibernate.Query;
+import org.hibernate.Session;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.orm.hibernate4.HibernateTemplate;
+import org.springframework.transaction.annotation.Transactional;
+
+@Repository
+public class GreetingDAO implements GreetingPersistence {
+    
+    @Autowired
+    private HibernateTemplate hibernateTemplate;
+    
+    @Override
+    @Transactional(readOnly=true)
+    public Greeting getGreeting(String text) {
+        if (getCurrentSession() == null) {
+            throw new NullPointerException("getCurrentSession() is null !");
+        }
+        List<Greeting> greetingList = null;
+        try {
+            Query q = getCurrentSession().createQuery("from Greeting as greeting where greeting.text=:text");
+            q.setParameter("text", text);
+            greetingList = (List<Greeting>) q.list();
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+        return greetingList.size() > 0 ? greetingList.get(0) : null;
+    }
+
+    @Override
+    @Transactional(readOnly=false)
+    public void addGreeting(String author, String text) {
+        Greeting greeting = new Greeting();
+        greeting.setAuthor(author);
+        greeting.setText(text);
+        hibernateTemplate.save(greeting);
+    }
+
+    @Override
+    @Transactional(readOnly=false)
+    public void updateGreeting(String author, String text) {
+        Greeting greeting = getGreeting(text);
+        if (greeting != null) {
+            greeting.setAuthor(author);
+            hibernateTemplate.save(greeting);
+        }
+    }
+
+    @Override
+    @Transactional(readOnly=false)
+    public void deleteGreeting(String text) {
+        Greeting greeting = getGreeting(text);
+        if (greeting != null) {
+            getCurrentSession().delete(greeting);
+        }
+    }
+
+    @Override
+    @Transactional(readOnly=true)
+    public List<Greeting> getGreetings() {
+        return (List<Greeting>) getCurrentSession()
+                .createCriteria(Greeting.class)
+                .setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY)
+                .list();
+    }
+    
+    private Session getCurrentSession() {
+        if (hibernateTemplate.getSessionFactory() == null) {
+            throw new NullPointerException("getSessionFactory() is null !");
+        }
+        return hibernateTemplate.getSessionFactory().getCurrentSession();
+    }
+}

src/main/java/com/hellogwt/server/persistence/GreetingMapper.java

@@ -22,7 +22,7 @@
 import org.apache.ibatis.annotations.Param;
 import org.apache.ibatis.annotations.Select;
 
-public interface GreetingMapper {
+public interface GreetingMapper extends GreetingPersistence {
 
     @Select("SELECT * FROM greetings WHERE text = #{text}")
     Greeting getGreeting(@Param("text") String text);

src/main/java/com/hellogwt/server/persistence/GreetingPersistence.java

@@ -0,0 +1,30 @@
+/**
+ * Common interface to test Hibernate and MyBatis.
+ *
+ * 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 com.hellogwt.server.persistence;
+
+import com.hellogwt.shared.domain.Greeting;
+import java.util.List;
+
+/**
+ * Common interface for Hibernate and MyBatis DAO/Mapper
+ */
+public interface GreetingPersistence {
+    public Greeting getGreeting(String text);
+    public void addGreeting(String author, String text);
+    public void updateGreeting(String author, String text);
+    public void deleteGreeting(String text);
+    public List<Greeting> getGreetings();
+}

src/main/java/com/hellogwt/shared/domain/Greeting.java

@@ -3,6 +3,10 @@
  * 
  * Class Greeting is used by server and client parts of application,
  * so it should be created in com.hellogwt.shared.domain package.
+ * 
+ * It is mandatory that this standard Java POJO implements java.io.Serializable
+ * or com.google.gwt.user.client.rpc.IsSerializable and has a no-argument
+ * constructor!
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,9 +23,18 @@
 package com.hellogwt.shared.domain;
 
 import java.io.Serializable;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.Table;
 
+@Entity  
+@Table(name= "greetings") 
 public class Greeting implements Serializable {
 
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Integer id;
     private String author;
     private String text;