Article summary

Summary

Discusses how to work with Sling Models within an AEM 6.3 project. Sling Models let you map Java objects to Sling resources. Also discusses how to use the Experience Manager Urber 6.3 JAR.

A special thank you to Ratna kumar kotla, top AEM community member, for testing this article to ensure it works.

Digital Marketing Solution(s) Adobe Experience Manager 6.3
Audience Developer
Required Skills CSS, HTML , Java
Version 6.3
Video N/A

Note:

You can download an AEM package that contains the code used in this article. Download the package and deploy using package manager. The purpose of this code is to show the community these concepts in action. That is, it's to illustrate how to write an AEM Sling Servlet that uses Sling Models. This community code is for teaching purposes only and not meant to go into production as is.

You can view the sample community application by using the following URL: http://localhost:4502/content/SlingModel63/en.html (assuming you deploy on author).

Note:

You must configure the System User and specify the system user within the Sling Mapper Service as discussed in this article before this example works correctly. 

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Introduction

You can work with Sling Models when developing with Adobe Experience Manager (AEM) 6.3. That is, when developing an Experience Manager project, you can define a model object (a Java object) and map that object to Sling resources. For more information, see Sling Models.

A Sling Model is implemented as an OSGi bundle. A Java class located in the OSGi bundle is annotated with @Model and the adaptable class (for example, @Model(adaptables = Resource.class). The data members (Fields) use @Inject annotations. These data members map to node properties. Consider the following Java class named UserInfo.

package SlingModel63.core;
 
import javax.inject.Inject;
 
import org.apache.sling.api.resource.Resource;
import org.apache.sling.models.annotations.Model;
  
@Model(adaptables = Resource.class)
public class UserInfo {
    @Inject
    private String firstName;
    @Inject
    private String lastName;
    @Inject
    private String technology;
      
    public String getFirstName() {
        return firstName;
    }
    public String getLastName() {
        return lastName;
    }
    public String getTechnology() {
        return technology;
    }
  
}

As you can see in the code example, the @Model annotation is used. Likewise, each data member in the UserInfo class is annotated using the @Inject annotation. This Java class is mapped to a Sling resource, like the one shown in the following illustatration.

crxde
A JCR node that is used in the Sling Model

Notice that the class members in the UserInfo class map to the String properties that belong to the /content/testsling/slingmodel node. This article walks you through creating a Sling Servlet that uses a Sling Model to map to this resource.

The following illustration shows the output of the Sling Servlet that uses Sling Models. Notice that the values in the node properties are displayed.

Client
An AEM web page displaying values returned from a Sling Servlet that uses Sling Models

Create a dedicated AEM user account

Create a dedicated Experience Manager user account that can access AEM JCR data located at content/customer. The user account must have both read and write privileges, as shown in the following illustration.

users
An AEM user account that has both read and write privileges to content/customers

Create a system user account for AEM 6.3 by performing these tasks: 

1. Open http://localhost:4502/crx/explorer/index.jsp.

2. Login as admin.

3. Click User Administration.

4. Click Create System User named data (data is used in this article).

5. Set the UserId.

6. Click Save

7. Access the AEM user page at http://localhost:4502/useradmin.

8. Select the data user.

9. From the right-hand pane, select the Permissions tab.

10. Expand the content tab and then select the customers row.

11. Click all the checkboxes that represent the permissions (click the top row in permissions for this example).

12. Click the Save button located in the top menu bar (located above the Path heading).

Configure the Experience Manager Sling Map Service

The next step is to configure the Apache Sling Service User Mapper service by adding a new entry. You specify the following value:

slingModel63.core:datawrite=data
where:

  • slingModel63.core – is the Bundle-SymbolicName value of the OSGi bundle this is developed in the upcoming sections of this article.
  • datawrite – the name of the sub service (you reference this value in a Java Map object)
  • data – the user account with data read/write privileges for content/customer. (In AEM 6.3, this must be a System User. 

The following illustration shows an entry for this service.

SlingMapping
An entry in the Apache Sling Service Mapping Service

To create an entry in the Apache Sling Mapper service, perform these tasks:

1. Go to the Apache Sling Mapper service at http://localhost:4502/system/console/configMgr.

2. Click OSGI, Configurations.

2. Scroll to an entry named Apache Sling Service User Mapper Service.

3. Enter the value slingModel63.core:datawrite=data.

4. Click Save.

Setup Maven in your development environment

You can use Maven to build an OSGi bundle that contains a Sling Servlet. Maven manages required JAR files that a Java project needs in its class path. Instead of searching the Internet trying to find and download third-party JAR files to include in your project’s class path, Maven manages these dependencies for you.

You can download Maven 3 from the following URL:

http://maven.apache.org/download.html

After you download and extract Maven, create an environment variable named M3_HOME. Assign the Maven install location to this environment variable. For example:

C:\Programs\Apache\apache-maven-3.0.4

Set up a system environment variable to reference Maven. To test whether you properly setup Maven, enter the following Maven command into a command prompt:

%M3_HOME%\bin\mvn -version

This command provides Maven and Java install details and resembles the following message:

Default locale: en_US, platform encoding: Cp1252
OS name: "windows 7", version: "6.1", arch: "amd64", family: "windows"

Note: It is recommended that you use Maven 3.0.3 or greater. For more information about setting up Maven and the Home variable, see: Maven in 5 Minutes.

Next, copy the Maven configuration file named settings.xml from [install location]\apache-maven-3.0.4\conf\ to your user profile. For example, C:\Users\scottm\.m2\.

You have to configure your settings.xml file to use Adobe’s public repository. For information, see Adobe Public Maven Repository at http://repo.adobe.com/.

Note:

The Adobe repository URL is now made secured. Change http://repo.adobe.com/nexus/content/groups/public/ to https://repo.adobe.com/nexus/content/groups/public/.

Create an AEM Maven 10 archetype project

You can create an archetype project by using the Maven archetype plugin. In this example, assume that the working directory is C:\AdobeCQ.

maven
Maven Archetype 10 generated files

To create an archetype project, perform these steps:

1. Open the command prompt and go to your working directory (for example, C:\AdobeCQ).

2. Run the following Maven command:

mvn archetype:generate -DarchetypeGroupId=com.adobe.granite.archetypes -DarchetypeArtifactId=aem-project-archetype -DarchetypeVersion=10 -DarchetypeRepository=https://repo.adobe.com/nexus/content/groups/public/

3. When prompted, specify the following information:

  • groupId - slingModel63
  • artifactId - slingModel63
  • version - 1.0-SNAPSHOT
  • package - com.foo.community
  • appsFolderName - SlingModel63 
  • artifactName - SlingModel63 
  • componentGroupName - SlingModel63
  • contentFolderName - SlingModel63 
  • cssId - SlingModel63
  • packageGroup -SlingModel63
  • siteName - SlingModel63 

4. WHen prompted, specify Y.

5. Once done, you will see a message like:

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 01:42 min
[INFO] Finished at: 2016-04-25T14:34:19-04:00
[INFO] Final Memory: 16M/463M
[INFO] ------------------------------------------------------------------------

6. Change the working directory to SlingModel63 and then enter the following command.

mvn eclipse:eclipse

After you run this command, you can import the project into Eclipse as discussed in the next section.

Add Java files to the Maven TagSightly10 project using Eclipse

To make it easier to work with the Maven generated project, import it into the Eclipse development environment, as shown in the following illustration.

project
Eclipse Import Dialog

The Eclipse project that you work in to build the OSGi bundle that uses Sling Models is slingModel63 core. You do not have to work in the other projects.

Note:

Do not worry about the errors reported in Eclipse. It does not read the POM file where the APIs are resolved. You build the bundle with Maven. Eclipse is used to edit the Java files and the POM file. Also, delete all files in the project except for the slingModel63.core package. Place the two Java files discussed in this article into this package.

UserInfo class

In the SlingModel63.core package, create a Java class named UserInfo. This class uses Sling Model annotations. The following Java code represents this class.

package com.foo.community.core;

import javax.inject.Inject;
 
import org.apache.sling.api.resource.Resource;
import org.apache.sling.models.annotations.Model;
  
@Model(adaptables = Resource.class)
public class UserInfo {
    @Inject
    private String firstName;
    @Inject
    private String lastName;
    @Inject
    private String technology;
      
    public String getFirstName() {
        return firstName;
    }
    public String getLastName() {
        return lastName;
    }
    public String getTechnology() {
        return technology;
    }
  
}

SlingModels class

Add a Java file to the SlingModel63.core package named SlingModels. The Java class that you create in this section extends the Java class named org.apache.sling.api.servlets.SlingAllMethodsServlet. This class is required to define an AEM Sling Servlet. For information, see Class SlingAllMethodsServlet.

The SlingModels class uses the following Sling Servlet annotation:

@SlingServlet(paths="/bin/slingmodel", methods="GET")

Notice that this servlet is defined as a GET. Later in this development article, an AJAX GET operation is used to invoke this operation.

The following Java code represents this class.

package com.foo.community.core;

import java.io.IOException;

import javax.servlet.ServletException;
  
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.sling.SlingServlet;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.resource.ResourceResolver;
import org.apache.sling.api.resource.ResourceResolverFactory;
import org.apache.sling.api.resource.ValueMap;
import org.apache.sling.api.servlets.SlingAllMethodsServlet;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.List;
import java.util.ArrayList;
import org.apache.sling.api.resource.Resource; 
import javax.jcr.Node; 
import java.util.Map;
import java.util.HashMap ; 
  
  
  
@SlingServlet(paths="/bin/slingmodel63", methods="GET")
public class SlingModels extends SlingAllMethodsServlet{
  
    private static final long serialVersionUID = 1L;
    Logger logger = LoggerFactory.getLogger(this.getClass());
    @Reference
    ResourceResolverFactory resolverFactory;    
    ResourceResolver resourceResolver;
    
    
    public void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response)throws ServletException,IOException{
        logger.info("inside sling model test servlet");
        response.setContentType("text/html");
        
        Map<String, Object> param = new HashMap<String, Object>();
        param.put(ResourceResolverFactory.SUBSERVICE, "datawrite");
        ResourceResolver resolver = null;
          
        try {
                     
        	//Invoke the adaptTo method to create a Session used to create a QueryManager
            resolver = resolverFactory.getServiceResourceResolver(param);
            Resource resource = resolver.getResource("/content/testsling/slingmodel");
           
                   
            ValueMap valueMap=resource.adaptTo(ValueMap.class);
            
            response.getWriter().write("Output from ValueMap is First Name: "+valueMap.get("firstName").toString()+" Last Name: "+valueMap.get("lastName").toString()+" Technology: "+valueMap.get("technology").toString()+"");
              
            UserInfo userInfo = resource.adaptTo(UserInfo.class);
            response.getWriter().write("Output from Sling Model is First Name: "+userInfo.getFirstName()+" Last Name: "+userInfo.getLastName()+" Technology: "+userInfo.getTechnology());
                      
        } catch (Exception e) {
            logger.error(e.getMessage());
        }
        finally{
            
        	//if(resourceResolver.isLive())
            	//resourceResolver.close();
        }
          
      
    }
  
}

Notice that the Resource object's adaptTo method is used to UserInfo object:

UserInfo userInfo = resource.adaptTo(UserInfo.class);

This is possible because Sling Model annotations are used in the UserInfo class. Finally this servlet returns the value of the UserInfo object.

 

response.getWriter().write("Output from Sling Model is First Name: "+userInfo.getFirstName()+" Last Name: "+userInfo.getLastName()+" Technology: "+userInfo.getTechnology());

Modify the Maven POM file

Add the following POM dependency to the POM file located at C:\AdobeCQ\slingModel63.

 <dependency>
               <groupId>com.adobe.aem</groupId>
               <artifactId>uber-jar</artifactId>
               <version>6.3.0</version>
               <!-- for AEM6.1 use this version     : <version>6.1.0</version> -->
               <!-- for AEM6.1 SP1 use this version : <version>6.1.0-SP1-B0001</version> -->
               <!-- for AEM6.1 SP2 use this version : <version>6.1.0-SP2</version> -->
               <!-- for AEM6.2 use this version     : <version>6.2.0</version> -->
               <classifier>obfuscated-apis</classifier>
               <scope>provided</scope>
           </dependency>
             
           <dependency>
               <groupId>org.apache.geronimo.specs</groupId>
               <artifactId>geronimo-atinject_1.0_spec</artifactId>
               <version>1.0</version>
               <scope>provided</scope>
           </dependency>

You need to modify two POM files. The first one is the parent POM file shown in this illustration.

PPom
Parent POM

Add the dependency shown above to the Parent POM file. In the following POM file, notice this plugin element.

<plugin>
<groupId>org.apache.felix</groupId>
<artifactId>maven-scr-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.felix</groupId>
<artifactId>maven-bundle-plugin</artifactId>
<extensions>true</extensions>
<configuration>
<instructions>
<Bundle-SymbolicName>SlingModel63-Core</Bundle-SymbolicName>
<Sling-Model-Packages>SlingModel63.core</Sling-Model-Packages>
</instructions>
</configuration>
</plugin>

This is required to ensure the model is adaptable. In this example, the UserInfo class is located in the SlingModel63.core package. Without this plugin element, the model returns null. Next modify the POM file located at C:\AdobeCQ\slingModel63\core.

The following code represents this POM file.

<?xml version="1.0" encoding="UTF-8"?>
<!--
 |  Copyright 2015 Adobe Systems Incorporated
 |
 |  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.
-->
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>slingModel63</groupId>
        <artifactId>slingModel63</artifactId>
        <version>1.0-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>
    <artifactId>slingModel63.core</artifactId>
    <packaging>bundle</packaging>
    <name>slingModel63 - Core</name>
    <description>Core bundle for slingModel63</description>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.felix</groupId>
                <artifactId>maven-scr-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.apache.felix</groupId>
                <artifactId>maven-bundle-plugin</artifactId>
                <extensions>true</extensions>
                <configuration>
                    <instructions>
                        <!--
                        <Embed-Dependency>
                            artifactId1,
                            artifactId2;inline=true
                        </Embed-Dependency>
                        -->
                        <Sling-Model-Packages>
                            com.foo.community.core
                        </Sling-Model-Packages>
                    </instructions>
                </configuration>
            </plugin>
        </plugins>
    </build>
    <profiles>
        <!-- Development profile: install only the bundle -->
        <profile>
            <id>autoInstallBundle</id>
            <activation>
                <activeByDefault>false</activeByDefault>
            </activation>
            <build>
                <plugins>
                    <plugin>
                        <groupId>org.apache.sling</groupId>
                        <artifactId>maven-sling-plugin</artifactId>
                        <configuration>
                            <!-- Note that this requires /apps/slingModel63/install to exist!!          -->
                            <!--    This is typically the case when ui.apps is deployed first                -->
                            <!--    Otherwise, create /apps/slingModel63/install manually (CRXDE|Lite)  -->
                            <slingUrlSuffix>/apps/slingModel63/install/</slingUrlSuffix>
                            <failOnError>true</failOnError>
                        </configuration>
                    </plugin>
                </plugins>
            </build>
        </profile>
    </profiles>
    <dependencies>
     
 <!-- OSGi Dependencies -->
             
        <dependency>
            <groupId>com.adobe.aem</groupId>
            <artifactId>uber-jar</artifactId>
            <classifier>obfuscated-apis</classifier>
        </dependency>
  
        <dependency>
            <groupId>org.apache.geronimo.specs</groupId>
            <artifactId>geronimo-atinject_1.0_spec</artifactId>
        </dependency>
        <dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>servlet-api</artifactId>
    <version>2.5</version>
</dependency>
 
        <dependency>
            <groupId>org.apache.felix</groupId>
            <artifactId>org.apache.felix.scr</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.felix</groupId>
            <artifactId>org.apache.felix.scr.annotations</artifactId>
        </dependency>
        <dependency>
            <groupId>biz.aQute</groupId>
            <artifactId>bndlib</artifactId>
        </dependency>
        <dependency>
            <groupId>org.osgi</groupId>
            <artifactId>org.osgi.core</artifactId>
        </dependency>
        <dependency>
            <groupId>org.osgi</groupId>
            <artifactId>org.osgi.compendium</artifactId>
        </dependency>
        <!-- Other Dependencies -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
        </dependency>
        <dependency>
            <groupId>javax.jcr</groupId>
            <artifactId>jcr</artifactId>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
        </dependency>
        <dependency>
            <groupId>com.adobe.aem</groupId>
            <artifactId>aem-api</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.sling</groupId>
            <artifactId>org.apache.sling.models.api</artifactId>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-all</artifactId>
        </dependency>
        <dependency>
            <groupId>junit-addons</groupId>
            <artifactId>junit-addons</artifactId>
        </dependency>
    </dependencies>
</project>

Build the OSGi bundle using Maven

To build the OSGi bundle by using Maven, perform these steps:

  1. Open the command prompt and go to the C:\AdobeCQ\slingModel63.
  2. Run the following maven command: mvn -PautoInstallPackage install.
  3. The OSGi component can be found in the following folder:  C:\AdobeCQ\slingModel63\core\target. The file name of the OSGi component is slingModel63.core-1.0-SNAPSHOT.jar.

The command -PautoInstallPackage automatically deploys the OSGi bundle to AEM.

Modify the SlingModel63 page to invoke the Servlet

Modify the SlingModel63 example page to perform a GET request to the Sling Servlet that was created in this development article. In this example, a JQuery Ajax GET request is made and the data returned from the Sling Servlet is displayed in the page.Delete page.html and replace it with page.jsp located here: /apps/SlingModel62/components/structure/page. 

CRXDE2
Add a file name page.jsp

Add the following code to page.jsp. 

<%@include file="/libs/foundation/global.jsp"%>
<cq:includeClientLib categories="cq.jquery" />
<html>
<head>
<meta charset="UTF-8">
<title>Adobe Experience Manager Sling Model Page</title>
<style>
body {background-color:lightgray}
h1   {color:red}
p    {color:green}
</style>
</style>
<script>
 
$(document).ready(function() {
   
    $('body').hide().fadeIn(5000);
          
$('#submit').click(function() {
    var failure = function(err) {
             alert("Unable to retrive data "+err);
   };
   
 
    //Use JQuery AJAX to perform a GET to the AEM Sling Servlet that uses Sling Models
    $.ajax({
         type: 'GET',    
         url:'/bin/slingmodel63',
         success: function(msg){
             $('#json').val(msg);   
         }
     });
  });
      
}); // end ready
</script>
</head>
     
<title>Adobe Experience Manager Sling Model Page</title>
     
<body>
       
            
<h1>Adobe Experience Manager Sling Model </h1>
           
</div>
           
<form method="#">
             
 <table border="1" align="left">
   
 
 <tr>
 <td></td>
   
  <td>
<textarea id="json" rows="15" cols="50">
</textarea>
 </td>
   
 </tr> 
   
 <tr>
 <td></td>
 <td>
<input type="button" value="Get Sling Model Data"  name="submit" id="submit">
 
 </td>
   
 </tr> 
   
 </table>
  
</form>
     
             
  
   
</body>
   
</html>

View an AEM web page that displays Sling Servlet data

The final task is to view the example page that displays data from the Sling Servlet that uses Sling Models. Enter the following URL into a web browser: 

http://localhost:4502/content/SlingModel62/en.html

The following page appears. Click Get Sling Model Data and you will view the data. 

Client
Data returned from the Sling Servlet that uses a Sling Model

See also

Join the AEM community at: Adobe Experience Manager Community

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