I would like to demonstrate a real world web application using Hibernate. Step by step, you can create an application which allows to edit books.

We will implement

This should take you about 15 minutes, if everything runs fine and assuming that you have Maven installed and that you have some experience to deploy a web application to a servlet engine.

Setup the project (5 minute)

You need an Internet connection and you need to have Maven installed. http://maven.apache.org/ I have used Maven version 3.

In a shell input the following command. This needs to be on one line.

mvn -DarchetypeVersion=5.2.5 -Darchetype.interactive=false -DarchetypeArtifactId=quickstart \
 -Dversion=1.0-SNAPSHOT  -DarchetypeGroupId=org.apache.tapestry  -DgroupId=de.laliluna \
 -Dpackage=de.laliluna.helloworld -DartifactId=helloworld --batch-mode \
 -DarchetypeRepository=http://tapestry.apache.org archetype:generate

It will setup a new quickstart project. If you prefer to setup the project manually, have a look in the Tapestry articles on my website http://www.laliluna.de

To have a first look at your application, tell Maven to download the dependencies. Type the following command in a shell.

cd helloworld
mvn dependency:resolve

# Start an internal web server
mvn jetty:run

Visit http://localhost:8080/helloworld in your browser.

We are going to use the Tapestry Hibernate Module. In addition we need to add the JDBC driver for the database.

Edit the Maven build file myPathToTheProject/helloworld/pom.xml

In the section <dependencies> add the following dependency:

Maven pom.xml. 

<dependencies>

    <dependency>
        <groupId>org.apache.tapestry</groupId>
        <artifactId>tapestry-hibernate</artifactId>
        <version>${tapestry-release-version}</version>
    </dependency>

    <dependency>
        <groupId>postgresql</groupId>
        <artifactId>postgresql</artifactId>
        <version>8.3-603.jdbc3</version>
    </dependency>

<!-- more dependencies -->

Change into the directory helloworld and let Maven resolve the libraries.

cd helloworld
mvn dependency:resolve

Import and run the project

IntelliJ and Netbeans support Maven out of the box. Eclipse requires the M2Eclipse plugin.

Alternatively using Eclipse you may type the following to create normal eclipse project files.

mvn eclipse:eclipse

Inside of your IDE deploy the project to a webserver like Tomcat or Jetty.

Add a Hibernate configuration (1 minute)

src/main/resources/hibernate.cfg.xml. 

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>

  <session-factory>
      <property name="hbm2ddl.auto">create-drop</property>

    <property name="connection.url">
      jdbc:postgresql://localhost:5432/play
    </property>
    <property name="connection.username">postgres</property>
    <property name="connection.password">p</property>
    <property name="connection.driver_class">
      org.postgresql.Driver
    </property>
    <property name="dialect">
      org.hibernate.dialect.PostgreSQLDialect
    </property>
    <property name="cache.provider_class">
      org.hibernate.cache.NoCacheProvider
    </property>


  <mapping class="de.laliluna.helloworld.domain.Book"/>

  </session-factory>

</hibernate-configuration>

Create the book entity (1 minute)

src/main/java/de/laliluna/helloworld/Book.java. 

@Entity
public class Book {

    @GeneratedValue
    @Id
    private Integer id;
    private String title;

    @Temporal(TemporalType.DATE)
    private Date published;

    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder();
        sb.append("Book");
        sb.append("{id=").append(id);
        sb.append(", title='").append(title).append('\'');
        sb.append(", published=").append(published);
        sb.append('}');
        return sb.toString();
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public Date getPublished() {
        return published;
    }

    public void setPublished(Date published) {
        this.published = published;
    }

}

Create a sortable data grid (3 minutes)

In the Index.tml page, we are going to add the grid.

Index.tml. 

<html t:type="layout" title="newapp Index"
      t:sidebarTitle="Current Time"
      xmlns:t="http://tapestry.apache.org/schema/tapestry_5_1_0.xsd"
      xmlns:p="tapestry:parameter">

<t:grid source="allBooks" />
... snip ...

Tapestry has a concept of a template and a corresponding Java class. The template can access properties of the Java class. As the grid uses allBooks, we need to add a getAllBooks method to the Index.java class.

Index.java. 

import org.apache.tapestry5.ioc.annotations.Inject;
import org.hibernate.Session;

import java.util.*;

/**
 * Start page of application newapp.
 */
public class Index
{

    @Inject
    private Session session;

   public List<Book> getAllBooks(){
      return session.createQuery("select b from Book b").list();
   }

... snip ...

Redeploy your application and have a look at your sortable data grid.

As it is annoying, to have an empty grid, we will add an action link to create random books. An action link calls an action method on the Java class.

Index.tml. 

<html t:type="layout" title="helloworld Index"
      t:sidebarTitle="Current Time"
      xmlns:t="http://tapestry.apache.org/schema/tapestry_5_1_0.xsd"
      xmlns:p="tapestry:parameter">

        <div>
      <t:actionlink t:id="createRandomBook">Create a random book</t:actionlink>
      </div>
        <t:grid source="allBooks" />
... snip ...

The corresponding action method in the Index.java file creates a book. Please take care that the method name corresponds to the t:id of the action link. Tapestry uses a lot of conventions like that. As the method returns null, you will stay on the same page.

Index.java. 

public class Index{

    @Inject
    private Session session;

    @CommitAfter
    public Object onActionFromCreateRandomBook(){
        session.save(new Book("Hibernate " + new Random().nextInt(100),
         new Date()));
        return null;
    }
... snip ...

You should be able to create books, see them in the table and sort them by now.

Dialog to create a book (4 minutes)

Of course, you need to create real books as well and input the data.

Create a new template for the dialog.

/src/main/resources/de/laliluna/helloworld/pages/CreateBook.tml. 

<html t:type="layout" title="Create a book"
      t:sidebarTitle="Current Time"
      xmlns:t="http://tapestry.apache.org/schema/tapestry_5_1_0.xsd"
      xmlns:p="tapestry:parameter">

<t:beaneditform exclude="id" object="book"/>

</html>

The t:beaneditform is a powerful Tapestry component which creates a dialog directly from your model. The model must be provided in the corresponding Java class. In addition, the CreateBook.java class has a onSuccess method being called, when the form is submitted.

/src/main/java/de/laliluna/helloworld/pages/CreateBook.java. 

public class CreateBook {

    /*
    @Property makes the book available to the EditBook.tml page.
     */
    @Property
    private Book book;

    @Inject
    private Session session;

    /*
    Inject a page. It is used later for navigation purpose.
     */
    @InjectPage
    private Index index;

    /**
     * Commit the transaction using {@code session.getTransaction().commit()}
     * right after themethod was executed.
     */
    @CommitAfter
    Object onSuccess() {
        session.saveOrUpdate(book);
        /*
        Return the injected page to navigate to the page.
         */
        return index;
    }
}

Finally, add a link to your index.tml to be able to navigate to the new page.

<div>
    <t:pagelink page="CreateBook">Create a new book</t:pagelink>
</div>

The t:beaneditform component is powerful because it is flexible. You can override each input elements and adapt it to your needs. Let’s add a character LOB to the book and a <textarea> input to the dialog.

Book.java. 

@Entity
public class Book {

    @Lob
    private String description;

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }
... snip ...

We need to change the CreateBook.tml to override the description to make use of an textarea.

CreateBook.tml. 

<html t:type="layout" title="Create a book"
      t:sidebarTitle="Current Time"
      xmlns:t="http://tapestry.apache.org/schema/tapestry_5_1_0.xsd"
      xmlns:p="tapestry:parameter">

<t:beaneditform exclude="id" object="book">
    <t:parameter name="description">
        <t:label for="description">My description</t:label>
        <t:textarea t:id="description" value="book.description"/>
    </t:parameter>
</t:beaneditform>
</html>

Just check that everything is working.

Editing a book (3 minutes)

In order to open an edit book dialog, we will modify the table displaying all books. Clicking on the book title in the grid, should allow you to edit a book. We need to modify how the title is rendered in the grid, add a new template for the edit dialog and a corresponding Java class with the Hibernate code to update the book.

The link first:

Modify the t:grid component. We override the cell for the title.

Index.tml. 

<t:grid source="allBooks" row="book">
    <p:titleCell>
        <t:pagelink page="EditBook" context="book.id">${book.title}</t:pagelink>
    </p:titleCell>

</t:grid>

The grid makes use of a book property to store the current book while iterating. Therefor the corresponding Java class Index.java needs to provide such a property. Add the following code.

Index.java. 

@Property
private Book book;

Create a new template.

/src/main/resources/de/laliluna/helloworld/pages/EditBook.tml. 

<html t:type="layout" title="Edit a book"
      t:sidebarTitle="Current Time"
      xmlns:t="http://tapestry.apache.org/schema/tapestry_5_1_0.xsd"
      xmlns:p="tapestry:parameter">

<t:beaneditform exclude="id" object="book">
    <t:parameter name="description">
        <t:label for="description">Description</t:label>
        <t:textarea t:id="description" value="book.description"/>
    </t:parameter>
</t:beaneditform>

</html>

Create the corresponding Java class.

/src/main/java/de/laliluna/helloworld/pages/EditBook.java. 

public class EditBook {

    /*
    @Property makes the book available to the EditBook.tml page.
     */
    @Property
    private Book book;

    @Inject
    private Session session;

    /*
    Inject a page. It is used later for navigation purpose.
     */
    @InjectPage
    private Index index;

    /**
     * Is called before the page is rendered. A value encoder provided by the
     * Tapestry Hibernate module, knows how to convert the id at the end of the
     *  URL localhost:8080/editbook/2 into an instance of {@link Book}
     * @param book the book to edit
     */
    void onActivate(Book book){
        this.book = book;
    }

    /**
     * On redirecting to the same page for example, if validation fails, it
     * is required to make Tapestry aware of the page context object.
     *
     * Otherwise you will loose the information which book was edited.
     * @return the edited book
     */
    Book onPassivate(){
        return book;
    }

    /**
     * Commit the transaction using {@code session.getTransaction().commit()}
     * right after the method was executed.
     */
    @CommitAfter
    Object onSuccess() {
        session.saveOrUpdate(book);
        /*
        Return the injected page to navigate to the page.
         */
        return index;
    }
}

You have completed a first web application using Hibernate.

public class EditBook {

    @Inject
    private Session session;