Writing your first OSGI Service in Liferay 7

• Create a folder : D:\Workspace\Liferay7
  Open your command prompt as Administrator
  
  C:\windows\system32>cd D:\Workspace\Liferay7
  
  C:\windows\system32>d:
  
  D:\Workspace\Liferay7>
• Execute the below command
  D:\Workspace\Liferay7>mvn archetype:generate -DarchetypeGroupId=com.liferay -DarchetypeArtifactId=com.liferay.project.templates.service -DgroupId=com.mindtree -DartifactId=com.mindtree.sample.service -DserviceClass=SampleService -DclassName=SampleServiceImpl -DinteractiveMode=false -Dauthor=AtifAliSiddiqui 
  
  Note:
  - Before executing the above command, make sure you have installed Maven on your machine.
  
  Output ::
  [INFO] Scanning for projects...
  [INFO]
  [INFO] ------------------------------------------------------------------------
  [INFO] Building Maven Stub Project (No POM) 1
  [INFO] ------------------------------------------------------------------------
  [INFO]
  [INFO] >>> maven-archetype-plugin:3.0.0:generate (default-cli) > generate-sources @ standalone-pom >>>
  [INFO]
  [INFO] <<< maven-archetype-plugin:3.0.0:generate (default-cli) < generate-sources @ standalone-pom <<<
  [INFO]
  [INFO] --- maven-archetype-plugin:3.0.0:generate (default-cli) @ standalone-pom ---
  [INFO] Generating project in Batch mode
  [INFO] Archetype [com.liferay:com.liferay.project.templates.service:1.0.2] found in catalog remote
  Downloading: https://repo.maven.apache.org/maven2/com/liferay/com.liferay.project.templates.service/1.0.2/com.liferay.project.templates.service-1.0.2.pom
  Downloaded: https://repo.maven.apache.org/maven2/com/liferay/com.liferay.project.templates.service/1.0.2/com.liferay.project.templates.service-1.0.2.pom (2 KB at 1.6 KB/sec)
  Downloading: https://repo.maven.apache.org/maven2/com/liferay/com.liferay.project.templates.service/1.0.2/com.liferay.project.templates.service-1.0.2.jar
  Downloaded: https://repo.maven.apache.org/maven2/com/liferay/com.liferay.project.templates.service/1.0.2/com.liferay.project.templates.service-1.0.2.jar (5 KB at 5.1 KB/sec)
  [INFO] ----------------------------------------------------------------------------
  [INFO] Using following parameters for creating project from Archetype: com.liferay.project.templates.service:1.0.2
  [INFO] ----------------------------------------------------------------------------
  [INFO] Parameter: groupId, Value: com.mindtree
  [INFO] Parameter: artifactId, Value: com.mindtree.sample.service
  [INFO] Parameter: version, Value: 1.0-SNAPSHOT
  [INFO] Parameter: package, Value: com.mindtree
  [INFO] Parameter: packageInPathFormat, Value: com/mindtree
  [INFO] Parameter: version, Value: 1.0-SNAPSHOT
  [INFO] Parameter: package, Value: com.mindtree
  [INFO] Parameter: groupId, Value: com.mindtree
  [INFO] Parameter: projectType, Value: standalone
  [INFO] Parameter: className, Value: SampleServiceImpl
  [INFO] Parameter: author, Value: AtifAliSiddiqui
  [INFO] Parameter: serviceClass, Value: SampleService
  [INFO] Parameter: artifactId, Value: com.mindtree.sample.service
  [INFO] Project created from Archetype in dir: D:\Workspace\Liferay7\com.mindtree.sample.service
  [INFO] ------------------------------------------------------------------------
  [INFO] BUILD SUCCESS
  [INFO] ------------------------------------------------------------------------
  [INFO] Total time: 23.892 s
  [INFO] Finished at: 2017-03-15T17:05:24+05:30
  [INFO] Final Memory: 17M/209M
  [INFO] ------------------------------------------------------------------------
• Please verify the generated directory structure looks as classified below
  
  - com.mindtree.sample.service
  ----- src
  --------- main
  ------------- java
  ----------------- com
  --------------------- mindtree
  ------------------------- SampleServiceImpl.java
  ------------- resources
  ----------------- .gitkeep
  ----- .gitignore
  ----- bnd.bnd
  ----- build.gradle
  ----- pom.xml
  
• Import this maven project into eclipse.
  
  - Open up eclipse.
  - Mention the Workspace as "D:\Workspace\Liferay7".
  - On the Left hand side, Package Explorer. Right click and select Import.
  - Expand "Maven", choose "Existing Maven Projects".
  - Root Directory - "D:\Workspace\Liferay7".
  - The maven project we just created should appear and be selected under projects. Click Finish.
  
• ​Do the following
  
  - Create following folder structure "D:\Workspace\Liferay7\com.mindtree.sample.service\src\main\java\com\mindtree\service\impl"
  
  - Create "SampleService.java" class under "D:\Workspace\Liferay7\com.mindtree.sample.service\src\main\java\com\mindtree\service", add the following code in the class file:
  
  package com.mindtree.service;
  public interface SampleService {
  public int add(int number1, int number2);
  }
  
  - Update the "SampleServiceImpl.java" class under "D:\Workspace\Liferay7\com.mindtree.sample.service\src\main\java\com\mindtree", add the following code in the class file:
  
  package com.mindtree.service.impl;
  import org.osgi.service.component.annotations.Component;
  import com.mindtree.service.SampleService;
  /**
  * @author AtifAliSiddiqui
  */
  @Component(
  immediate = true,
  property = {
  // TODO enter required service properties
  },
  service = SampleService.class
  )
  public class SampleServiceImpl implements SampleService {
  @Override
  public int add(int number1, int number2) {
  // TODO Auto-generated method stub
  return 0;
  }
  // TODO enter required service methods
  }
  
  - Move the "SampleServiceImpl.java" class under "D:\Workspace\Liferay7\com.mindtree.sample.service\src\main\java\com\mindtree\service\impl"
  
• Bundle Activator: 
  We need the OSGI framework to understand the service we created, for this we need to register the service in the framework.
  We can use bundle activator to register our service.
  
  - Create following folder structure "D:\Workspace\Liferay7\com.mindtree.sample.service\src\main\java\com\mindtree\activator"
  - Create "ServiceActivator.java" class under "D:\Workspace\Liferay7\com.mindtree.sample.service\src\main\java\com\mindtree\activator", add the following code in the class file:
  
  package com.mindtree.activator;
  import com.mindtree.service.SampleService;
  import com.mindtree.service.impl.SampleServiceImpl;
  import org.osgi.framework.BundleActivator;
  import org.osgi.framework.BundleContext;
  import org.osgi.framework.ServiceRegistration;
  public class ServiceActivator implements BundleActivator {
  private ServiceRegistration registration;
  @Override
  public void start(BundleContext context) throws Exception {
  registration = context.registerService(SampleService.class.getName(), new SampleServiceImpl(), null);
  System.out.println("###########Service Registered Successfully##############");
  }
  @Override
  public void stop(BundleContext context) throws Exception {
  registration.unregister();
  System.out.println("###########Service Unregistered##############");
  
  }
  }
  
  - Update the "bnd.bnd" under "D:\Workspace\Liferay7\com.mindtree.sample.service\", modify the content:
  
  Bundle-Name: com.mindtree.sample.service
  Bundle-SymbolicName: com.mindtree
  Bundle-Version: 1.0-SNAPSHOT
  Bundle-Activator: com.mindtree.activator.ServiceActivator
  Export-Package: com.mindtree.service
  
• Lets build our Project / Portlet
  
  - In Eclipse select "Run" -> "Run Configurations"
  - Right click "Maven Build" -> New
  - Name :: Build Service
  - Base directory :: ${workspace_loc:/com.mindtree.sample.service}
  - Goal :: clean package
  - Click Apply
  - Click Run
  - Check in Console if the Build is Successful
  
• ​Lets Deploy our Portlet to Liferay
  
  - Start up your Liferay7 instance, if not already running.
  - Copy the "com.mindtree.sample.portlet-1.0-SNAPSHOT.jar" from "D:\Workspace\Liferay7\com.mindtree.sample.portlet\target".
  - Paste "com.mindtree.sample.portlet-1.0-SNAPSHOT.jar" to "D:\Liferay\Community Edition 7.0\liferay-ce-portal-7.0-ga3\deploy".
  - See Liferay console / logs on the deployment of your portlet.
  
  to browse Liferay’s default SOAP web services:
  
  http://localhost:8080/api/axis
  
  To browse Liferay’s default JSON web services, visit this URL:
  
  http://localhost:8080/api/jsonws/
  
  Important:
  Check the namespace given in service.xml. In this case its "Sample".
  Search for contextName = sample.
  
  http://localhost:8080/api/jsonws?contextName=sample