Article summary

Summary

Discusses how to use the Sling API to query resources that belong to a closed user group (CUG). This article was written based on community feedback from the AEM forums. 

This article uses an Adobe Maven Archetype project to build an OSGi bundle. If you are not familiar with an Adobe Maven Archetype project, it is recommended that you read the following article: Creating your first AEM Service using an Adobe Maven Archetype project.

A special thank you to Ratna Kumar Kotla, a top AEM community member, for testing this community article to ensure it works. 

In this article, an AEM System user is created to obtain resources that belong to a CUG. These users cannot be used to log in normally, only by background processes. The admin user is not a system user, so you cannot use the admin user in a service user mapping like this. You have to create a new system user and assign them the appropriate permissions.If you would like to read more of the background on this change, take a look at https://issues.apache.org/jira/browse/SLING-3854.

This article was tested on AEM 6.1 with a valid system user and it functions as described in the article. 

Note: To run this code on the AEM Publisher Instance, you must create the System user on the Publisher instance. 

Digital Marketing Solution(s) Adobe Experience Manager (Adobe CQ)
Audience
Developer (intermediate)
Required Skills
Java, HTML, Maven
AEM Versions(s) Adobe Experience Manager 6.1

Note:

You can download an AEM package that contains code and the OSGi bundle that are 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 use the Sling API to query AEM resources that belong to a Closed User Group (CUG). 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/SlingQuery.html (assuming you deploy on author). 

Aftering installing the package, it is still necessary to perform these tasks:

  • create an AEM system user (or system user for AEM 6.1) named datacug with the permissions specified in this article
  • map the user with the Sling Mapper service
  • create the Closed User Group, named membersonly, and add the specified Test pages - as described in this article.  

You must perform these tasks, as outlined in this document, prior to running this sample. 

Download

Introduction

You can create an Adobe Experience Manager (AEM) application that queries AEM resources located in the AEM Java Content Repository (JCR) and part of a Closed User Group. To query AEM resources, you can use the Sling API from within an OSGi bundle to retrieve a resource from within the AEM JCR. To use the Sling API from within an OSGi component, you inject an org.apache.sling.api.resource.ResourceResolverFactory instance into the service. See Interface ResourceResolverFactory.

To use the Sling API to query AEM resources that belong to a CUG, you have to use an AEM System user that meet these requirements:

  • belongs to the CUG
  • has read permissions to the AEM resources

For example, consider the following AEM page resouces that are children pages to /content/geometrixx/en/toolbar/contacts

 

AA
AEM Pages that belong to a CUG

Application logic that queries data from the JCR is implemented as an OSGi bundle that is built using Declarative Services (DS) and Maven. DS is used to inject a ResourceResolverFactory instance into the service. The OSGi bundle is a managed component, which means that the OSGi service container creates the ResourceResolverFactory instance.

Note:

Make sure that you pages look like the previous illustration. 

Create a closed user group pages

To follow along with this development article, create a Closed User Group (CUG) named membersonly. To create a CUG, see the following AEM documentation topic: CREATING THE USER GROUP TO BE USED.

After you setup the CUG, create five new pages that are children of this page: 

http://localhost:4502/siteadmin#/content/geometrixx/en/toolbar/contacts

Name the pages Test1, Test2, Test3, Test4, and Test5 (it does not matter what AEM template you use). Next, make these pages part of the membersonly CUG. See APPLYING YOUR CLOSED USER GROUP TO CONTENT PAGES.

Make sure that each Test page has the CUG group defined (under the Advanced tab), as shown in this illustration of Test1 properties dialog.

Props
Test1 page properties

Extend READ permissions to the membersonly group under /content, as shown here. 

memberPermissions
membersonly group has READ permission to /content

Create an AEM application folder structure

Create an AEM application folder structure that contains templates, components, and pages by using CRXDE Lite.

CQAppSetup

The following describes each application folder:

  • application name: contains all of the resources that an application uses. The resources can be templates, pages, components, and so on.
  • components: contains components that your application uses. 
  • page: contains page components. A page component is a script such as a JSP file. 
  • global: contains global components that your application uses.
  • template: contains templates on which you base page components. 
  • src: contains source code that comprises an OSGi component (this development article does not create an OSGi bundle using this folder). 
  • install: contains a compiled OSGi bundles container.

To create an AEM application folder structure:

  1. Go to CRXDE Lite at http://localhost:4502/crx/de/index.jsp
  2. Right-click the apps folder (or the parent folder), select Create, Create Folder.
  3. Enter the folder name into the Create Folder dialog box. Enter jcrquerycug
  4. Repeat steps 1-4 for each folder specified in the previous illustration. 
    Click the Save All button.

Note:

You have to click the Save All button when working in CRXDE Lite for the changes to be made.

Create a template

You can create a template by using CRXDE Lite. An AEM template enables you to define a consistent style for the pages in your application. A template comprises of nodes that specify the page structure. For more information about templates, see Templates.

To create a template, perform these tasks:

1. Go to CRXDE Lite at http://localhost:4502/crx/de/index.jsp.
2. Right-click the template folder (within your application), select Create, Create
Template.
3. Enter the following information into the Create Template dialog box:

  • Label: The name of the template to create. Enter templateCUG
  • Title: The title that is assigned to the template.
  • Description: The description that is assigned to the template.
  • Resource Type: The component's path that is assigned to the template and copied to implementing pages. Enter jcrquerycug/components/page/templateCUG.
  • Ranking: The order (ascending) in which this template will appear in relation to other templates. Setting this value to 1 ensures that the template appears first in the list.

4. Add a path to Allowed Paths. Click on the plus sign and enter the following value: /content(/.*)?
5. Click Next for Allowed Parents.
6. Select OK on Allowed Children.

Create a render component that uses the template

Components are re-usable modules that implement specific application logic to render the content of your web site. You can think of a component as a collection of scripts (for example, JSPs, Java servlets, and so on) that completely realize a specific function. In order to realize this functionality, it is your responsibility as a CQ developer to create scripts that perform specific functionality. For more information about components, see Components.

By default, a component has at least one default script, identical to the name of the component. To create a render component, perform these tasks:

1. Go to CRXDE lite at http://localhost:4502/crx/de/index.jsp.
2. Right-click /apps/jcrquerycug/components/page, then select
Create, Create Component.
3. Enter the following information into the Create Component dialog box:

  • Label: The name of the component to create. Enter templateCUG
  • Title: The title that is assigned to the component.
  • Description: The description that is assigned to the template.
  • Super Type: foundation/components/page.

4. Select Next for Advanced Component Settings and Allowed Parents.
5. Select OK on Allowed Children.
6. Open the templateQueryjsp located at: /apps/jcrquerycug/components/page/templateCUG/templateCUG.jsp.
7. Enter the following JSP code.

<html>
<head>
<title>Hello World !!!</title>
</head>
<body>
<h1>Hello JCR!!!</h1>
<h2>This page will query pages that belong to an AEM CUG</h2>
</body>
</html>

Create a dedicated AEM user account

Create a dedicated AEM user account that can access AEM JCR data located at /content/geometrixx/en/toolbar/contacts. In this example, the datacug user has no permissions to the JCR, as shown in the following illustation (this user only has READ access to resources under /content by being a member of the membersonly group). 

CUGDataPermissions
datacug has no permission to the JCR

Create a System user account for AEM 6.1

To successfully query or persist data in AEM 6.1, you need to create an AEM System user. 

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

2. Login as admin.

3. Click User Administration.

4. Click Create System User named data (datacug 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 datacug user.

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

10. Expand the content tab and then select the permission row at top (for this example, all permissions are granted to datacug). 

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

12. Add the datacug to the Closed User Group named membersonly (this is very important). See ADDING USERS OR GROUPS TO A GROUP.

To add a user to a group, pull up the group in the Group user interface. Then on the left hand side, select the datacug users. Then click on membersonly and click the members tab. Then drag and drop the user from the left to the members tab, as shown here. 

CUGMembers
Adding a user to an AEM group

Note:

If you do not add datacug user to the CUG named membersonly, the Java code will not be abled to query the pages that belong to the CUG. 

Configure the AEM 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:

com.community.aem.slingapi-bundle:datacug=datacug

where:

  • com.community.aem.slingjcr-bundle – is the Bundle-SymbolicName value of the OSGi bundle this is developed in the upcoming sections of this article.
  • datacug– the name of the sub service (you reference this value in a Java Map object)
  • datacug– the AEM System user account with data read/write privileges (the system user created earlier in this development article).

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 com.community.aem.slingapi-bundle:datacug=datacug.

4. Click Save. 

Setup Maven in your development environment

You can use Maven to build an OSGi bundle that uses the JCR API and is deployed to Experience Manager. 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:

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/.

The following XML code represents a settings.xml file that you can use.

<?xml version="1.0" encoding="UTF-8"?>

<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you 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.
-->

<!--
 | This is the configuration file for Maven. It can be specified at two levels:
 |
 |  1. User Level. This settings.xml file provides configuration for a single user, 
 |                 and is normally provided in ${user.home}/.m2/settings.xml.
 |
 |                 NOTE: This location can be overridden with the CLI option:
 |
 |                 -s /path/to/user/settings.xml
 |
 |  2. Global Level. This settings.xml file provides configuration for all Maven
 |                 users on a machine (assuming they're all using the same Maven
 |                 installation). It's normally provided in 
 |                 ${maven.home}/conf/settings.xml.
 |
 |                 NOTE: This location can be overridden with the CLI option:
 |
 |                 -gs /path/to/global/settings.xml
 |
 | The sections in this sample file are intended to give you a running start at
 | getting the most out of your Maven installation. Where appropriate, the default
 | values (values used when the setting is not specified) are provided.
 |
 |-->
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0" 
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
          xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">
  <!-- localRepository
   | The path to the local repository maven will use to store artifacts.
   |
   | Default: ~/.m2/repository
  <localRepository>/path/to/local/repo</localRepository>
  -->

  <!-- interactiveMode
   | This will determine whether maven prompts you when it needs input. If set to false,
   | maven will use a sensible default value, perhaps based on some other setting, for
   | the parameter in question.
   |
   | Default: true
  <interactiveMode>true</interactiveMode>
  -->

  <!-- offline
   | Determines whether maven should attempt to connect to the network when executing a build.
   | This will have an effect on artifact downloads, artifact deployment, and others.
   |
   | Default: false
  <offline>false</offline>
  -->

  <!-- pluginGroups
   | This is a list of additional group identifiers that will be searched when resolving plugins by their prefix, i.e.
   | when invoking a command line like "mvn prefix:goal". Maven will automatically add the group identifiers
   | "org.apache.maven.plugins" and "org.codehaus.mojo" if these are not already contained in the list.
   |-->
  <pluginGroups>
    <!-- pluginGroup
     | Specifies a further group identifier to use for plugin lookup.
    <pluginGroup>com.your.plugins</pluginGroup>
    -->
  </pluginGroups>

  <!-- proxies
   | This is a list of proxies which can be used on this machine to connect to the network.
   | Unless otherwise specified (by system property or command-line switch), the first proxy
   | specification in this list marked as active will be used.
   |-->
  <proxies>
    <!-- proxy
     | Specification for one proxy, to be used in connecting to the network.
     |
    <proxy>
      <id>optional</id>
      <active>true</active>
      <protocol>http</protocol>
      <username>proxyuser</username>
      <password>proxypass</password>
      <host>proxy.host.net</host>
      <port>80</port>
      <nonProxyHosts>local.net|some.host.com</nonProxyHosts>
    </proxy>
    -->
  </proxies>

  <!-- servers
   | This is a list of authentication profiles, keyed by the server-id used within the system.
   | Authentication profiles can be used whenever maven must make a connection to a remote server.
   |-->
  <servers>
    <!-- server
     | Specifies the authentication information to use when connecting to a particular server, identified by
     | a unique name within the system (referred to by the 'id' attribute below).
     | 
     | NOTE: You should either specify username/password OR privateKey/passphrase, since these pairings are 
     |       used together.
     |
    <server>
      <id>deploymentRepo</id>
      <username>repouser</username>
      <password>repopwd</password>
    </server>
    -->
    
    <!-- Another sample, using keys to authenticate.
    <server>
      <id>siteServer</id>
      <privateKey>/path/to/private/key</privateKey>
      <passphrase>optional; leave empty if not used.</passphrase>
    </server>
    -->
  </servers>

  <!-- mirrors
   | This is a list of mirrors to be used in downloading artifacts from remote repositories.
   | 
   | It works like this: a POM may declare a repository to use in resolving certain artifacts.
   | However, this repository may have problems with heavy traffic at times, so people have mirrored
   | it to several places.
   |
   | That repository definition will have a unique id, so we can create a mirror reference for that
   | repository, to be used as an alternate download site. The mirror site will be the preferred 
   | server for that repository.
   |-->
  <mirrors>
    <!-- mirror
     | Specifies a repository mirror site to use instead of a given repository. The repository that
     | this mirror serves has an ID that matches the mirrorOf element of this mirror. IDs are used
     | for inheritance and direct lookup purposes, and must be unique across the set of mirrors.
     |
    <mirror>
      <id>mirrorId</id>
      <mirrorOf>repositoryId</mirrorOf>
      <name>Human Readable Name for this Mirror.</name>
      <url>http://my.repository.com/repo/path</url>
    </mirror>
     -->
  </mirrors>
  
  <!-- profiles
   | This is a list of profiles which can be activated in a variety of ways, and which can modify
   | the build process. Profiles provided in the settings.xml are intended to provide local machine-
   | specific paths and repository locations which allow the build to work in the local environment.
   |
   | For example, if you have an integration testing plugin - like cactus - that needs to know where
   | your Tomcat instance is installed, you can provide a variable here such that the variable is 
   | dereferenced during the build process to configure the cactus plugin.
   |
   | As noted above, profiles can be activated in a variety of ways. One way - the activeProfiles
   | section of this document (settings.xml) - will be discussed later. Another way essentially
   | relies on the detection of a system property, either matching a particular value for the property,
   | or merely testing its existence. Profiles can also be activated by JDK version prefix, where a 
   | value of '1.4' might activate a profile when the build is executed on a JDK version of '1.4.2_07'.
   | Finally, the list of active profiles can be specified directly from the command line.
   |
   | NOTE: For profiles defined in the settings.xml, you are restricted to specifying only artifact
   |       repositories, plugin repositories, and free-form properties to be used as configuration
   |       variables for plugins in the POM.
   |
   |-->
  <profiles>
    <!-- profile
     | Specifies a set of introductions to the build process, to be activated using one or more of the
     | mechanisms described above. For inheritance purposes, and to activate profiles via <activatedProfiles/>
     | or the command line, profiles have to have an ID that is unique.
     |
     | An encouraged best practice for profile identification is to use a consistent naming convention
     | for profiles, such as 'env-dev', 'env-test', 'env-production', 'user-jdcasey', 'user-brett', etc.
     | This will make it more intuitive to understand what the set of introduced profiles is attempting
     | to accomplish, particularly when you only have a list of profile id's for debug.
     |
     | This profile example uses the JDK version to trigger activation, and provides a JDK-specific repo.
    <profile>
      <id>jdk-1.4</id>

      <activation>
        <jdk>1.4</jdk>
      </activation>

      <repositories>
        <repository>
          <id>jdk14</id>
          <name>Repository for JDK 1.4 builds</name>
          <url>http://www.myhost.com/maven/jdk14</url>
          <layout>default</layout>
          <snapshotPolicy>always</snapshotPolicy>
        </repository>
      </repositories>
    </profile>
    -->

    <!--
     | Here is another profile, activated by the system property 'target-env' with a value of 'dev',
     | which provides a specific path to the Tomcat instance. To use this, your plugin configuration
     | might hypothetically look like:
     |
     | ...
     | <plugin>
     |   <groupId>org.myco.myplugins</groupId>
     |   <artifactId>myplugin</artifactId>
     |   
     |   <configuration>
     |     <tomcatLocation>${tomcatPath}</tomcatLocation>
     |   </configuration>
     | </plugin>
     | ...
     |
     | NOTE: If you just wanted to inject this configuration whenever someone set 'target-env' to
     |       anything, you could just leave off the <value/> inside the activation-property.
     |
    <profile>
      <id>env-dev</id>

      <activation>
        <property>
          <name>target-env</name>
          <value>dev</value>
        </property>
      </activation>

      <properties>
        <tomcatPath>/path/to/tomcat/instance</tomcatPath>
      </properties>
    </profile>
    -->
  

<profile>

                <id>adobe-public</id>

                <activation>

                    <activeByDefault>true</activeByDefault>

                </activation>

                <repositories>

                  <repository>

                    <id>adobe</id>

                    <name>Nexus Proxy Repository</name>

                    <url>http://repo.adobe.com/nexus/content/groups/public/</url>

                    <layout>default</layout>

                  </repository>

                </repositories>

                <pluginRepositories>

                  <pluginRepository>

                    <id>adobe</id>

                    <name>Nexus Proxy Repository</name>

                    <url>http://repo.adobe.com/nexus/content/groups/public/</url>

                    <layout>default</layout>

                  </pluginRepository>

                </pluginRepositories>

            </profile>

</profiles>

  <!-- activeProfiles
   | List of profiles that are active for all builds.
   |
  <activeProfiles>
    <activeProfile>alwaysActiveProfile</activeProfile>
    <activeProfile>anotherAlwaysActiveProfile</activeProfile>
  </activeProfiles>
  -->
</settings>

Create an Experience Manager archetype project

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

Maven

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 -DarchetypeRepository=https://repo.adobe.com/nexus/content/groups/public/ -DarchetypeGroupId=com.day.jcr.vault -DarchetypeArtifactId=multimodule-content-package-archetype -DarchetypeVersion=1.0.2 -DgroupId=com.community.aem -DartifactId=slingapi -Dversion=1.0-SNAPSHOT -Dpackage=com.community.aem -DappsFolderName=myproject -DartifactName="My Project" -DcqVersion="5.6.1" -DpackageGroup="My Company"

3. When prompted for additional information, specify Y.

[[INFO] Total time: 14:46.131s
[INFO] Finished at: Wed Mar 27 13:38:58 EDT 2013
[INFO] Final Memory: 10M/184M

 

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 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

Note:

Delete all files and packages created by the Maven project. Keep the com.community.aem package. Add the three Java files to this package as specified in this article. 

The next step is to add Java files that use the Sling API. For information, see Sling API Overview.

Add the following Java files to your project:

  • A Java interface named Query (add this interface to the com.community.aem package)
  • A Java class named QueryImp that implements the Query interface (add this class to the com.community.aem.impl package)

Query interface

The following code represents the Query interface. This interface contains a method signature named getJCRData. The implementation logic for this method is located in the QueryImp class. 

The following Java code represents the Query interface. 

package com.community.aem;

public interface Query {

	
	public String getJCRData(String location) ;
}

QueryImp class

The QueryImpl class uses the following Apache Felix SCR annotations to create the OSGi component:

  • @Component – defines the class as a component
  • @Service - defines the service interface that is provided by the component
  • @Reference – injects a service into the component. 

Note:

For information, see Apache Felix SCR annotations.

In this development article, a ResourceResolverFactory instance is injected into the getJCRData method. This instance is required to create a Resource instance. To inject a ResourceResolverFactory instance, you use the @Reference annotation to define a class member, as shown in the following example.

//Inject a Sling ResourceResolverFactory
@Reference
private ResourceResolverFactory resolverFactory;

Within the getJCRData method, you reference the datacug entry that you specified in the Apache Sling Mapper service. You use datacug to create a Resource object, as shown here.

@Reference
	private ResourceResolverFactory resolverFactory;
	
	/** Default log. */
	protected final Logger log = LoggerFactory.getLogger(this.getClass());
     
@Override
public String getJCRData(String location) {
	
	
	Map<String, Object> param = new HashMap<String, Object>();
	param.put(ResourceResolverFactory.SUBSERVICE, "datacug");
	
	  
	try {
	             
	    
		//Get the title of the AEM web page at this specific location - assume its a value such as /content/geometrixx/en/services
	     ResourceResolver resourceResolver = resolverFactory.getServiceResourceResolver(param);
	     Resource res = resourceResolver.getResource(location);

In this example, the following location is passed to this method: /content/geometrixx/en/toolbar/contacts (this is passed from the JSP). Because the System User used to create a Resource object belongs to the CUG, it has access to the child pages (that belong to the CUG) of contacts (ensure that you setup the child pages at the start of this article). 

The child pages are queried and their details are written to the AEM log file.  The following Java code represents the QueryImpl class. 

package com.community.aem.impl;


import org.w3c.dom.Document;
import org.w3c.dom.Element;
  
  
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
  
import java.io.StringWriter;
import java.util.Iterator;
import java.util.List;
import java.util.ArrayList;
import java.util.HashMap; 
import java.util.Map; 
  
import javax.jcr.Repository; 
import javax.jcr.SimpleCredentials; 
import javax.jcr.Node; 
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
   
import org.apache.jackrabbit.commons.JcrUtils;
  
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
  
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Service;
import javax.jcr.RepositoryException;
import org.apache.felix.scr.annotations.Reference;
import org.apache.jackrabbit.commons.JcrUtils;
  
import javax.jcr.Session;
import javax.jcr.Node; 
import com.community.aem.*; 
 
 //Sling Imports
import org.apache.sling.api.resource.ResourceResolverFactory ; 
import org.apache.sling.api.resource.ResourceResolver; 
import org.apache.sling.api.resource.Resource; 
import com.day.cq.wcm.api.Page; 
import com.day.cq.wcm.api.PageFilter; 
 
//This is a component so it can provide or consume services
@Component
 
  
@Service
public class QueryImp implements Query {
 

	//Inject a Sling ResourceResolverFactory
	@Reference
	private ResourceResolverFactory resolverFactory;
	
	/** Default log. */
	protected final Logger log = LoggerFactory.getLogger(this.getClass());
     
@Override
public String getJCRData(String location) {
	
	
	Map<String, Object> param = new HashMap<String, Object>();
	param.put(ResourceResolverFactory.SUBSERVICE, "datacug");
	
	  
	try {
	             
	    
		//Get the title of the AEM web page at this specific location - assume its a value such as /content/geometrixx/en/services
	     ResourceResolver resourceResolver = resolverFactory.getServiceResourceResolver(param);
	     Resource res = resourceResolver.getResource(location);
		
		
		             
	     //Adapts the resource to another type - in this example to a     com.day.cq.wcm.api.page
	     Page page = res.adaptTo(Page.class);

	     String title = page.getTitle(); // Get the title of the web page


	     //Write out the CUG Pages - the user datacug belongs to the UCG that has access to these pages 
	     Iterator<Page> it = page.listChildren() ;

	     while (it.hasNext()) {
	
	    	 	String name = (String) it.next().getPath(); 
	    	 	log.info("**** CUG Child pages are: "+name);
	     }


return title ; // return title of the page 
}
catch (Exception e)
{
    e.printStackTrace()  ; 
}
         
return null;
    }
 
}

Modify the Maven POM file

Modify the POM files to successfully build the OSGi bundle. In the POM file located at C:\AdobeCQ\slingapi\bundle, add the following dependencies.

  • org.apache.felix.scr
  • org.apache.felix.scr.annotations
  • org.apache.jackrabbit
  • org.apache.sling

The following XML represents this POM file.
 

<?xml version="1.0" encoding="UTF-8"?>
<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/maven-v4_0_0.xsd ">
    <modelVersion>4.0.0</modelVersion>
    <!-- ====================================================================== -->
    <!-- P A R E N T P R O J E C T D E S C R I P T I O N -->
    <!-- ====================================================================== -->
    <parent>
        <groupId>com.community.aem</groupId>
        <artifactId>slingapi</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <!-- ====================================================================== -->
    <!-- P R O J E C T D E S C R I P T I O N -->
    <!-- ====================================================================== -->

    <artifactId>slingapi-bundle</artifactId>
    <packaging>bundle</packaging>
    <name>My Project Bundle</name>

<dependencies>
         
          
        
      <dependency>
        <groupId>com.adobe.aem</groupId>
        <artifactId>aem-api</artifactId>
        <version>6.0.0.1</version>
        <scope>provided</scope>
    </dependency>
         
         
   <dependency>
    <groupId>org.apache.sling</groupId>
    <artifactId>org.apache.sling.api</artifactId>
    <version>2.8.0</version>
</dependency>
  
         
        <dependency>
            <groupId>org.osgi</groupId>
            <artifactId>org.osgi.compendium</artifactId>
        </dependency>
        <dependency>
            <groupId>org.osgi</groupId>
            <artifactId>org.osgi.core</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.felix</groupId>
            <artifactId>org.apache.felix.scr.annotations</artifactId>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
        </dependency>
           
            
        <dependency>
         <groupId>org.apache.felix</groupId>
     
         <artifactId>org.osgi.core</artifactId>
     
         <version>1.4.0</version>
      </dependency>
           
          
            
    <dependency>
    <groupId>org.apache.jackrabbit</groupId>
    <artifactId>jackrabbit-core</artifactId>
    <version>2.4.3</version>
    </dependency>
         
    <dependency>
    <groupId>org.apache.jackrabbit</groupId>
    <artifactId>jackrabbit-jcr-commons</artifactId>
    <version>2.4.3</version>
    </dependency>
   <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
        </dependency>
             
     
           
      <dependency>
         <groupId>javax.jcr</groupId>
         <artifactId>jcr</artifactId>
         <version>2.0</version>
      </dependency>
         
       <dependency>
            <groupId>com.day.cq.wcm</groupId>
            <artifactId>cq-wcm-api</artifactId>
            <version>5.5.0</version>
            <scope>provided</scope>
        </dependency>
           
        <dependency>
            <groupId>com.day.cq</groupId>
            <artifactId>cq-commons</artifactId>
            <version>5.5.0</version>
            <scope>provided</scope>
        </dependency>
                 
    </dependencies>
    <!-- ====================================================================== -->
    <!-- B U I L D D E F I N I T I O N -->
    <!-- ====================================================================== -->
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.felix</groupId>
                <artifactId>maven-scr-plugin</artifactId>
                <executions>
                    <execution>
                        <id>generate-scr-descriptor</id>
                        <goals>
                            <goal>scr</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.felix</groupId>
                <artifactId>maven-bundle-plugin</artifactId>
                <extensions>true</extensions>
                <configuration>
                    <instructions>
                        <Bundle-SymbolicName>com.community.aem.slingapi-bundle</Bundle-SymbolicName>
                    </instructions>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.sling</groupId>
                <artifactId>maven-sling-plugin</artifactId>
                <configuration>
                    <slingUrl>http://${crx.host}:${crx.port}/apps/myproject/install</slingUrl>
                    <usePut>true</usePut>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-javadoc-plugin</artifactId>
                 <configuration>
                    <excludePackageNames>
                        *.impl
                    </excludePackageNames>
                 </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Build the OSGi bundle using Maven

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

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

Deploy the bundle to Experience Manager

Once you deploy the OSGi bundle, you are able to invoke the getJCRData method defined in the QueryImp class (this is shown later in this development article).

OSGi

Deploy the OSGi bundle by performing these steps:

  1. Login to Apache Felix Web Console at http://server:port/system/console/bundles (default admin user = admin with password= admin).
  2. Click the Bundles tab, sort the bundle list by Id, and note the Id of the last bundle.
  3. Click the Install/Update button.
  4. Browse to the bundle JAR file you just built using Maven. (C:\AdobeCQ\slingapi\bundle\target).
  5. Click Install.
  6. Click the Refresh Packages button.
  7. Check the bundle with the highest Id.
  8. Click Active. Your new bundle should now be listed with the status Active.
    If the status is not Active, check the CQ error.log for exceptions.

Modify the TemplateCUG JSP

Modify the templateCUG.jsp file to invoke the getJCRData method that is defined by the QueryImpl class that uses the Sling API. The argument of this method is a string value that specifies the location of the JCR content. For example, /content/geometrixx/en/toolbar/contacts.

To invoke this service, you call sling.getService method as shown in the following example.

<%@include file="/libs/foundation/global.jsp"%>
<%@taglib prefix="cq" uri="http://www.day.com/taglibs/cq/1.0" %>
<h1>TemplateSling Page</h1>
<%
//create a custom.sling.Query instance
com.community.aem.Query wfService = sling.getService(com.community.aem.Query.class);

%>
<h2>Use the AEM Sling API to get title of the resource at /content/geometrixx/en/toolbar/contacts</h2>
  
<h3>The title of the page is: <%=  wfService.getJCRData("/content/geometrixx/en/toolbar/contacts")%></h3>

Modify the templateCUG JSP file

  1. Go to CRXDE Lite at http://localhost:4502/crx/de/index.jsp
  2. Double-click /apps/jcrquerycug/components/page/templateCUG/templateCUG.jsp.
  3. Replace the JSP code with the new code shown in this section.
  4. Click Save All.

Create an AEM web page that queries the JCR

The final task is to create a site that contains a page that is based on the templateCUG (the template created earlier in this development article). When the page is loaded, the service is invoked and the child pages that belong to the CUG are queries. The CUG page's data is written to the AEM log file, as shown here.

**** CUG Child pages are: /content/geometrixx/en/toolbar/contacts/Test1

**** CUG Child pages are: /content/geometrixx/en/toolbar/contacts/Test2

**** CUG Child pages are: /content/geometrixx/en/toolbar/contacts/Test3

**** CUG Child pages are: /content/geometrixx/en/toolbar/contacts/Test4

**** CUG Child pages are: /content/geometrixx/en/toolbar/contacts/Test5

The following illustration shows the client AEM web page. 

ClientPage
Client AEM web page displays data returned by the Sling API

Create a AEM web page that queries and persists data from the AEM JCR:

  1. Go to the CQ Websites page at http://localhost:4502/siteadmin#/content.
  2. Select New Page.
  3. Specify the title of the page in the Title field.
  4. Specify the name of the page in the Name field.
  5. Select templateCUG from the template list that appears. This value represents the template that is created in this development article. If you do not see it, then repeat the steps in this development article. For example, if you made a typing mistake when entering in path information, the template will not show up in the New Page dialog box.
  6. Open the new page that you created by double-clicking it in the right pane. The new page opens in a web browser. You should see a page similar to the previous illustration.
  7. To interact with the application in the Touch UI view, ensure that you place in the page in Preview mode. 

See also

Congratulations, you have just created an AEM 6.1 application that queries JCR data by using the Sling API> Please refer to the AEM community page for other articles that discuss how to build AEM services/applications by using an Adobe Maven Archetype project.

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