Generating Model, Persistence, and Service Code

Generating Model, Persistence, and Service Code

Service Builder makes it easy to define models and generate model, persistence, and service code for them. You’ll experience this by defining a model called Y7G4Entry and generating code using Service Builder. Then you’ll deploy your code to DXP and invoke a service that uses the code.

Download the Example Project

Download and unzip the example project.

curl -O

The liferay-y7g4 project has two modules:

  • y7g4-api
  • y7g4-service

The API module (-api) provides the public interfaces and utilities. The service module (-service) provides the implementation.

Examine the API Module

The API module has only a bnd metadata file and a Gradle build file.

 ├── bnd.bnd // Defines the module artifact, package exports, and includes the service XML file
 └── build.gradle // Declares dependencies

Here’s the bnd.bnd file:

Bundle-Name: Acme Y7G4 API
Bundle-SymbolicName: com.acme.y7g4.api
Bundle-Version: 1.0.0

The Bundle- headers describe the module artifact. The Export-Package header specifies the API packages to publish. See Module Projects for details on bnd metadata and how it’s used.

The build.gradle file declares the module’s dependency on DXP/Portal.

dependencies {
	compileOnly group: "com.liferay.portal", name: "release.portal.api"

Examine the Service Module

The Service Module has a bnd metadata file, a Gradle build file, and a service definition file.

 ├── bnd.bnd // Defines the module artifact, data schema version, and more
 ├── build.gradle // Declares dependencies and code generation parameters
 └── service.xml // Specifies models and their relationships

Here’s the bnd.bnd file:

Bundle-Name: Acme Y7G4 Service
Bundle-SymbolicName: com.acme.y7g4.service
Bundle-Version: 1.0.0
Liferay-Require-SchemaVersion: 1.0.0
Liferay-Service: true
-dsannotations-options: inherit

Once again, the Bundle- headers describe the module artifact. Service metadata and a directive follow.

Metadata Description
Liferay-Require-SchemaVersion: 1.0.0 Your application’s data schema version. When you release application versions that have database schema changes, you’ll increment the version.
Liferay-Service: true The module provides a Liferay Service.
-dsannotations-options: inherit OSGi service component classes inherit OSGi Declarative Services annotations from their class hierarchy. For example, extension classes can access all the services that ancestor fields reference via the @Reference annotation.

Here’s the build.gradle file:

buildService {
	apiDir = "../y7g4-api/src/main/java"

dependencies {
	compileOnly group: "com.liferay.portal", name: "release.portal.api"
	compileOnly project(":y7g4-api")

The buildService task generates the service’s API classes to the API module Java source folder specified by apiDir. The service module depends on DXP/Portal and the API module (in the sibling folder y7g4-api).

Examine the Service Model Definition

The service.xml file defines the Y7G4Entry model entity. Service Builder generates model, persistence, and service classes per the service.xml file’s specification.

Here’s the service.xml file:

<?xml version="1.0"?>
<!DOCTYPE service-builder PUBLIC "-//Liferay//DTD Service Builder 7.4.0//EN" "">

<service-builder dependency-injector="ds" package-path="com.acme.y7g4" short-no-such-exception-enabled="false">
	<entity local-service="true" name="Y7G4Entry" remote-service="false">

		<!-- PK fields -->

		<column name="y7g4EntryId" primary="true" type="long" />

		<!-- Other fields -->

		<column name="description" type="String" />
		<column name="name" type="String" />

This file defines a Y7G4Entry model that has an ID (the primary key), name, and description.

service-builder Element

The service-builder element attributes affect all model entities in the service.xml file.

service-builder attribute Description
dependency-injector Declares the dependency injector type. Declarative Services (ds) is the default.
package-path Declares the leading package path for the generated classes.
short-no-such-exception-enabled If set to true, use a truncated version of the entity name in NoSuchY7G4EntryException messages; otherwise use the complete entity name.

namespace Element

The global namespace element specifies the prefix for all the model entity database tables.

entity Element

entity elements define model database tables and service types.

entity attributes Description
name The entity’s name. Service Builder generates an entity table using the naming format [namespace]_[name] (for example, Y7G4_Y7G4Entry).
local-service If true, generate service classes to call from within the JVM.
remote-service If true, generate service classes, including web services classes, to call from outside of the JVM.

column Elements

Each column element defines a column in the entity’s table. Here are the Y7G4Entry entity column elements:

Column Description
y7g4EntryId the model instance’s ID (long integer) and primary key.
name the instance’s name (string).
description the instance’s description (string).

For more information on service.xml elements, see the Liferay Service Builder DTD.

Generate the Persistence Code

Invoke Service Builder to generate persistence code and database scripts.

cd liferay-y7g4
./gradlew y7g4-service:buildService


> Task :y7g4-service:buildService
Building Y7G4Entry
Writing src/main/java/com/acme/y7g4/service/persistence/impl/
Writing ../y7g4-api/src/main/java/com/acme/y7g4/service/persistence/
Writing ../y7g4-api/src/main/java/com/acme/y7g4/service/persistence/
Writing src/main/java/com/acme/y7g4/service/persistence/impl/
Writing src/main/java/com/acme/y7g4/model/impl/
Writing src/main/java/com/acme/y7g4/model/impl/
Writing src/main/java/com/acme/y7g4/model/impl/
Writing ../y7g4-api/src/main/java/com/acme/y7g4/model/
Writing ../y7g4-api/src/main/java/com/acme/y7g4/model/
Writing src/main/java/com/acme/y7g4/model/impl/
Writing ../y7g4-api/src/main/java/com/acme/y7g4/model/
Writing ../y7g4-api/src/main/java/com/acme/y7g4/model/
Writing ../y7g4-api/src/main/java/com/acme/y7g4/model/
Writing src/main/java/com/acme/y7g4/service/impl/
Writing src/main/java/com/acme/y7g4/service/base/
Writing ../y7g4-api/src/main/java/com/acme/y7g4/service/
Writing ../y7g4-api/src/main/java/com/acme/y7g4/service/
Writing ../y7g4-api/src/main/java/com/acme/y7g4/service/
Writing src/main/resources/META-INF/module-hbm.xml
Writing src/main/resources/META-INF/portlet-model-hints.xml
Writing ../y7g4-api/src/main/java/com/acme/y7g4/exception/
Writing src/main/java/com/acme/y7g4/service/persistence/impl/constants/
Writing src/main/resources/META-INF/sql/tables.sql
Writing src/main/resources/META-INF/sql/tables.sql
Writing src/main/resources/

1 actionable task: 1 executed

Service Builder generates Java classes, database scripts, and configuration files for the model, persistence, and services. The file paths are relative to the y7g4-service module.

Here’s an overview of the generated structure:

├── y7g4-api
│   └── src
│       └── main
│           └── java
│               └── com
│                   └── acme
│                       └── y7g4
│                           ├── exception // Public exception classes & interfaces
│                           ├── model // Public model classes & interfaces
│                           └── service // Public persistence and service classes
│                                       // & interfaces
└── y7g4-service
    └── src/main
        ├── java/com/acme/y7g4
        │                 ├── model // Model implementation
        │                 └── service // Persistence and service implementation
        └── resources
            ├── META-INF
            │   ├── module-hbm.xml // Hibernate object relational map configuration
            │   ├── portlet-model-hints.xml // Provides field type information for the UI
            │   └── sql
            │       ├── indexes.sql
            │       ├── sequences.sql
            │       └── tables.sql
            └── // Tracks the service build version

The model, persistence, and service implementation classes were generated to the Java package path com.acme.y7g4. Learn about the classes at Understanding Service Builder Generated Classes.

SQL scripts and the persistence configuration were generated to the resources/META-INF folder.

The module-hbm.xml file specifies the Hibernate object relational map.

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "">

<hibernate-mapping auto-import="false" default-lazy="false">
    <import class="com.acme.y7g4.model.Y7G4Entry" />
    <class name="com.acme.y7g4.model.impl.Y7G4EntryImpl" table="Y7G4_Y7G4Entry">
        <id access="com.liferay.portal.dao.orm.hibernate.LiferayPropertyAccessor" name="y7g4EntryId" type="long">
            <generator class="assigned" />
        <property access="com.liferay.portal.dao.orm.hibernate.LiferayPropertyAccessor" name="description" type="com.liferay.portal.dao.orm.hibernate.StringType" />
        <property access="com.liferay.portal.dao.orm.hibernate.LiferayPropertyAccessor" name="name" type="com.liferay.portal.dao.orm.hibernate.StringType" />

The module-hbm.xml file maps Y7G4EntryImpl objects to the Y7G4_Y7G4Entry table. For more information on mapping with Hibernate, visit Hibernate.

The tables.sql script specifies the Y7G4_Y7G4Entry table.

create table Y7G4_Y7G4Entry (
    y7g4EntryId LONG not null primary key,
    description VARCHAR(75) null,
    name VARCHAR(75) null

y7g4EntryId is the primary key. name and description are attributes. When you deploy the module, DXP/Portal creates the table by running the tables.sql script.

Since this service.xml file’s elements don’t specify indexes or sequences, the indexes.sql or sequences.sql scripts are empty.

Deploy the Persistence Layer and Services

It’s time to create the persistence layer and services by deploying the generated code to a DXP server. The server uses a data source on a separate MariaDB database server—it’s easier to examine a database on MariaDB than the bundled Hypersonic server. After deploying everything, you’ll verify the tables and test the services.

Create the Database

  1. Start a MariaDB Docker container.

    docker run --name some-mariadb -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mariadb:10.2
  2. Create the DXP database from within the MariaDB Docker container.

    Sign in to the database server.

    docker exec -it some-mariadb bash -c "/usr/bin/mysql -uroot -pmy-secret-pw"

    Create a database for DXP.

    create database dxp_db character set utf8;

    End your database session.

  3. Get the MariaDB container IP address by invoking Docker’s network inspect]( command on the default network (bridge)

    docker network inspect bridge

Example output:

"Containers": {
    "162f5350ee9ba7c47c1ba91f54a84543aeada7feb35eb8153743b13ef54cb491": {
        "Name": "some-mariadb",
        "EndpointID": "8e97e35fb118e2024a52f2ecbfd40b0a879eba8dc3bc5ffceea8bb117c10bebc",
        "MacAddress": "02:42:ac:11:00:02",
        "IPv4Address": "",
        "IPv6Address": ""

Use the first part of the IPv4Address value for the some-mariadb container. The IP address from the example is

Start the Server

In a separate terminal, start DXP using the following command. Make sure to replace [IP address] with the some-mariadb container IP address.

docker run -it \
--add-host some-mariadb:[IP address] \
-e LIFERAY_JDBC_PERIOD_DEFAULT_PERIOD_URL="jdbc:mariadb://some-mariadb:3306/dxp_db?useUnicode=true&characterEncoding=UTF-8&useFastDateParsing=false" \
-m 8g \
-p 8080:8080 \

Deploy the Modules

Deploy the modules to create the database table and to install the services.

./gradlew deploy$(docker ps -lq)

Console output:

STARTED com.acme.y7g4.service_1.0.0 [1423]
STARTED com.acme.y7g4.api_1.0.0 [1422]

Check the Tables

Verify and validate the database table.

  1. Sign in to the database server.

    docker exec -it some-mariadb bash -c "/usr/bin/mysql -uroot -pmy-secret-pw"
  2. Connect to the database.

    connect dxp_db;
  3. List the database tables to verify the Y7G4_Y7G4Entry table.

    show tables;


    | Tables_in_dxp_db               |
    | AMImageEntry                   |
    | AccountEntry                   |
    | AccountEntryOrganizationRel    |
    | ...                            |
    | Y7G4_Y7G4Entry                 |
  4. List the Y7G4_Y7G4Entry table columns.



    | Field       | Type        | Null | Key | Default | Extra |
    | y7g4EntryId | bigint(20)  | NO   | PRI | NULL    |       |
    | description | varchar(75) | YES  |     | NULL    |       |
    | name        | varchar(75) | YES  |     | NULL    |       |

    Everything is in place.

  5. End your database session.


Test the Services

Invoke the services to populate the database with Y7G4Entry data.

  1. Visit DXP in your browser at http://localhost:8080.

  2. Sign in using the default credentials:

    User Name: [email protected]

    Password: test

  3. Navigate to the Script console at Control PanelServer AdministrationScript.

  4. Add an entry by executing the following script.

    import com.acme.y7g4.service.Y7G4EntryLocalServiceUtil;
    import com.liferay.portal.kernel.dao.orm.QueryUtil;
    entry = Y7G4EntryLocalServiceUtil.createY7G4Entry(1234);
    entry.setName("Mop floors");
    entry.setDescription("Mop the kitchen and bathroom floors with soap and water.");
    entries = Y7G4EntryLocalServiceUtil.getY7G4Entries(QueryUtil.ALL_POS, QueryUtil.ALL_POS);
    for (entry in entries){


    {y7g4EntryId=1234, description=Mop the kitchen and bathroom floors with soap and water., name=Mop floors}

    The newly added Y7G4Entry is printed in JSON format.

Here’s what the script did:

  1. Imported the generated static utility class Y7G4EntryLocalServiceUtil.
  2. Created a Y7G4Entry instance with the ID (long) 1234.
  3. Populated the Y7G4Entry instance’s name and description attributes.
  4. Added the Y7G4Entry to the database.
  5. Got all the Y7G4Entry instances from the database and printed them.

What’s Next

Now that you know how to define a model and generate persistence code and service code for it, you should examine the generated service classes. Continue with Understanding and Extending Generated Classes.