Article summary

Summary

Discusses how to create an Adobe Experience Manager (AEM) HTL component that queries data from the AEM JCR. This article creates an OSGi bundle that uses the JCR Query API to query and filter data. In addition, discusses how to invoke an OSGi bundle operation from the client web page.

This article uses the Sling method named getServiceResourceResolver to obtain a Session instance. This method replaces the use of the getAdministrativeResourceResolver method, which is deprecated in AEM 6.


resolver = resolverFactory.getServiceResourceResolver(param);

For more information, see Service Authentication.

Also discusses how to invoke an AEM service from an HTL Class that extends WCMUsePojo.

NOTE: In AEM 6.2, users must be system users, which effectively means that their node in the JCR is of type rep:SystemUser. See System users

AEM System 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 6.2 with a valid system user and it functions as described in the article. 

A special thank you to community members Dean Anderson and Greg Wells for contributing towards this article. In addition, thank you to Ratna Kumar Kotla for testing it to ensure it works. 

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, JCR SQL. HTML
AEM Versions(s) Adobe Experience Manager 6.2
Video N/A

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 write an OSGi bundle that contains a custom service that uses the getServiceResourceResolver method and how to invoke this from an HTL class that extends WCMUsePOJO. 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/editor.html/content/jcrHtl/en.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 data with the permissions
  • map the user with the Sling Mapper service 

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

Download

Introduction

You can create an Adobe Experience Manager (AEM) HTL (used to be known as Sightly) component that queries data located in the AEM Java Content Repository (JCR). To query data, you use an HTL Java class that extends the WCMUsePojo API and the javax.jcr.query.QueryManager instance that belongs to the JCR Query API. This API supports both searching and querying operations.

For example, assume that your AEM application tracks your organization’s customers. You can develop an AEM HTL component that is able to query the JCR to obtain a customer result set in which a digital marketer is interested.

intro2
JCR data displayed in an AEM web page

Assume that you have customer data in the AEM JCR.

JCRnodes

Using an HTL component that consists of a Java class that extends WCMUsePojo, you can retrieve the JCR data and display it.

Client
An AEM web page that displays data from the AEM JCR

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.

As of AEM 6, you get a session instance (required to work with the JCR API) by using a Sling method named getServiceResourceResolver(). This new method replaces the use of the following depreciated API code:

ResourceResolver resourceResolver = resolverFactory.getAdministrativeResourceResolver(null);
  session = resourceResolver.adaptTo(Session.class);

The following code shows use of the more secure getServiceResourceResolver API call. This code uses a specific AEM System User with JCR read and write privileges to access the AEM JCR.

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);
    session = resolver.adaptTo(Session.class);

Note:

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

Create a dedicated AEM user account

Create a dedicated AEM 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. 

user

Note:

The new user created should be assigned with read access rights at root (/). To create users in this example AEM app, you also need to give the new user JCR write access. 

 

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 (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 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:

jcrHtl.core:datawrite=data

where:

  • jcrHtl.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 6.2, this must be a System User. See the link at this beginning of this article to learn how to create a System user.)

The following illustration shows an entry for this service. 

SlingMapping

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 jcrHtl.core:datawrite=data.

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. 

fileSys
Default files created by a Maven 10 archetype project

To create an Experience Manager 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 - jcrHtl
  • artifactId - jcrHtl
  • version - 1.0-SNAPSHOT
  • package - com.community.htl
  • appsFolderName -  jcrHtl
  • artifactName - jcrHtl
  • componentGroupName - jcrHtl
  • contentFolderName - jcrHtl
  • cssId - jcrHtl
  • packageGroup -jcrHtl
  • siteName - jcrHtl

4. When prompted, specify Y.

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

[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 jcrHTL 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 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.

projectJCR

The next step is to add Java files to the com.community.htl.core package. The Java files that you create in this section use the Java JCR API.

Add the following Java files to the com.community.aem package:

  • A Java class named JCRHeroComponent that extends the WCMUsePojo API
  • A Java class named Customer that stores customer information.
  • A Java interface named CustomerService.
  • A Java class named CustomerServiceImp that implements the CustomerService interface and uses the JCR SQL2 API.

Customer class

The following code represents the Customer class that is used to store customer information. This class contains getter and setter methods that modify class members.

package com.community.htl.core;


//This bean holds customer information
public class Customer {
	
	//Define private class members
	private String custId ;
	private String first; 
	private String last; 
	private String address;
	private String description; 
	
	
	public void setCustId(String id)
	{
		this.custId = id; 
	}
	
	public String getCustId()
	{
		return this.custId;
	}
	
	public void setCustFirst(String first)
	{
		this.first = first; 
	}
	
	public String getCustFirst()
	{
		return this.first;
	}
	
	public void setCustLast(String last)
	{
		this.last = last; 
	}
	
	public String getCustLast()
	{
		return this.last;
	}
	
	public void setCustAddress(String address)
	{
		this.address = address; 
	}
	
	public String getCustAddress()
	{
		return this.address;
	}
	
	public void setCustDescription(String description)
	{
		this.description = description; 
	}
	
	public String getCustDescription()
	{
		return this.description;
	}

}

CustomerService interface

The following code represents the CustomerService interface. This interface contains a method signature named getCustomerData. The implementation logic for these method is located in the CustomerServiceImp class. The getCustomerData method uses the JCR API to query customer data from the AEM JCR.

The following Java code represents the CustomerService interface. 

package com.community.htl.core;


import java.util.List;

public interface CustomerService {
    
    
    /*
     * Retrieves customer data from the AEM JCR and returns all customer 
     * data within an XML schema
     *The filter argument specifies one of the following values:
     *     
     *Customer - retrieves all customer data
     *Active Customer- retrieves current customers from the JCR
     *Past Customer - retrieves old customers no longer current customers 
     */
    public List getCustomerData(String filter); 
     
}

CustomerServiceImp class

The CustomerServiceImp 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. 

In this development article, a ResourceResolverFactory instance is injected into the getCustomerData method. This instance is required to create a Session instance that lets you query the AEM JCR. 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 getCustomerData method, you reference the entry that you specified in the Apache Sling Mapper service. You use this to create a Session object, as shown here.

//This is a component so it can provide or consume services
@Component
  
@Service
public class CustomerServiceImpl implements CustomerService {
  
  
/** Default log. */
protected final Logger log = LoggerFactory.getLogger(this.getClass());
      
private Session session;
          
//Inject a Sling ResourceResolverFactory
@Reference
private ResourceResolverFactory resolverFactory;
      
 
 
//Queries the AEM JCR for customer data and returns
//the data within an XML schema   
public String getCustomerData(String filter) {
 
Customer cust = null;
 
List<Customer> custList = new ArrayList<Customer>();
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);
    session = resolver.adaptTo(Session.class);

Note:

When you open a JCR session, there is a reference to the JCR repository object. Every session will consume some memory unless the logout() method is called explicitly. If you do not call this call and create lots of sessions, you risk an out-of-memory exception by your JVM, which terminates the CQ instance. A single leaked session isn’t a problem, but if you have hundreds or thousands of leaked sessions, it might turn into a problem. For more information, see CQ development patterns – Sling ResourceResolver and JCR sessions.

The getCustomerData method returns an XML schema that contains customer data within a string. The JCR Query API is used to query the AEM JCR based on user input. In this example, the Description property of each Customer node stores either of these values:

  • Active Customer
  • Past Customer

Therefore the JCR query is setup to query all customer nodes, only active customer nodes, or only past customer nodes. This is achieved by querying the Description propery of all nt:unstructured nodes and seaching for the string value Customer (for all customer nodes), Active (only active customers), or Past (only past customers). 

//Set the query
// Obtain the query manager for the session ...
javax.jcr.query.QueryManager queryManager = session.getWorkspace().getQueryManager();
        
//Setup the query based on user input      
String sqlStatement="";
       
//Setup the query to get all customer records
if (filter.equals("All Customers"))
   sqlStatement = "SELECT * FROM [nt:unstructured] WHERE CONTAINS(desc, 'Customer')";
else if(filter.equals("Active Customer"))
    sqlStatement = "SELECT * FROM [nt:unstructured] WHERE CONTAINS(desc, 'Active')";
else if(filter.equals("Past Customer"))
    sqlStatement = "SELECT * FROM [nt:unstructured] WHERE CONTAINS(desc, 'Past')";
       	
javax.jcr.query.Query query = queryManager.createQuery(sqlStatement,"JCR-SQL2");

//Execute the query and get the results ...
javax.jcr.query.QueryResult result = query.execute();

In this example, JCR-SQL2 is used to query the AEM JCR. For information, see  http://www.day.com/specs/jcr/2.0/6_Query.html.

The following Java code represents the CustomerServiceImp class. For each customer node that is retrieved from the AEM JCR, a new Customer object is created and stored in an ArrayList. This collection object is returned to the class that extends WCMUsePojo and its contents are displayed in the HTL component that appears in the AEM web page.  

package com.community.htl.core;

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 javax.jcr.Repository; 
import javax.jcr.SimpleCredentials; 
import javax.jcr.Node; 
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.util.HashMap; 
import java.util.Map; 
     
import org.apache.jackrabbit.commons.JcrUtils;
    

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; 
   
   
//Sling Imports
import org.apache.sling.api.resource.ResourceResolverFactory;
import org.apache.sling.api.resource.ResourceResolver; 
import org.apache.sling.api.resource.Resource; 
    
    
//This is a component so it can provide or consume services
@Component
    
@Service
public class CustomerServiceImp implements CustomerService {
    
    
/** Default log. */
	protected final Logger log = LoggerFactory.getLogger(this.getClass());
        
private Session session;
            
//Inject a Sling ResourceResolverFactory
@Reference
private ResourceResolverFactory resolverFactory;
        
   
   
//Queries the AEM JCR for customer data and returns
//the data within an XML schema   
public List getCustomerData(String filter) {
   
Customer cust = null;
   
List<Customer> custList = new ArrayList<Customer>();
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);
    session = resolver.adaptTo(Session.class);
      
    
    log.info("IN THE getCustomerData method") ; 
    
    
    //Obtain the query manager for the session ...
    javax.jcr.query.QueryManager queryManager = session.getWorkspace().getQueryManager();
        
//Setup the quesry based on user input     
String sqlStatement="";
       
//Setup the query to get all customer records
if (filter.equals("All Customers"))
  sqlStatement = "SELECT * FROM [nt:unstructured] WHERE CONTAINS(desc, 'Customer')";
else if(filter.equals("Active Customer"))
sqlStatement = "SELECT * FROM [nt:unstructured] WHERE CONTAINS(desc, 'Active')";
else if(filter.equals("Past Customer"))
    sqlStatement = "SELECT * FROM [nt:unstructured] WHERE CONTAINS(desc, 'Past')";
           
javax.jcr.query.Query query = queryManager.createQuery(sqlStatement,"JCR-SQL2");
   
//Execute the query and get the results ...
javax.jcr.query.QueryResult result = query.execute();
   
//Iterate over the nodes in the results ...
javax.jcr.NodeIterator nodeIter = result.getNodes();
   
while ( nodeIter.hasNext() ) {
   
  //For each node-- create a customer instance
  cust = new Customer();
           
 javax.jcr.Node node = nodeIter.nextNode();
             
 //Set all Customer object fields
 cust.setCustFirst(node.getProperty("firstName").getString());
 cust.setCustLast(node.getProperty("lastName").getString());
 cust.setCustAddress(node.getProperty("address").getString());
 cust.setCustDescription(node.getProperty("desc").getString());
             
  //Push Customer to the list
  custList.add(cust);
  }
           
// Log out
 session.logout();    
return custList;               
               
}
catch(Exception e)
{
 e.printStackTrace();
}
return null;
}
   
       
/*
 * Determines if the content/customer node exists
 * This method returns these values:
 * -1 - if customer does not exist
 * 0 - if content/customer node exists; however, contains no children
 * number - the number of children that the content/customer node contains
*/
private int doesCustExist(Node content)
{
try
{
  int index = 0 ;
  int childRecs = 0 ;
        
java.lang.Iterable<Node> custNode = JcrUtils.getChildNodes(content, "customer");
Iterator it = custNode.iterator();
                 
 //only going to be 1 content/customer node if it exists
if (it.hasNext())
 {
 //Count the number of child nodes to customer
 Node customerRoot = content.getNode("customer");
 Iterable itCust = JcrUtils.getChildNodes(customerRoot);
 Iterator childNodeIt = itCust.iterator();
                
//Count the number of customer child nodes
while (childNodeIt.hasNext())
{
 childRecs++;
 childNodeIt.next();
}
 return childRecs;
  }
else
return -1; //content/customer does not exist
}
catch(Exception e)
{
    e.printStackTrace();
}
return 0;
 }
    
  
 }

JCRHeroComponent class

The JCRHeroComponent class extends the WCMUsePojo class and is the entry point used by the  the HTL component. The getSlingScriptHelper().getService() method is how you create a CustomerService object from within a HTL Java class that extends WCMUsePojo.

 

//Use getSlingScriptHelper().getService() to get an instance of the CustomerService
        custService = getSlingScriptHelper().getService(CustomerService.class);

If you attempted to create a Java object by using the new operation or @Reference, the code will not work and an exception is thrown.

The JCRHeroComponent class invokes the CustomerService object's getCustomerData method that returns a List instance that contains a JCR result set that is displayed in the HTL component (see the illustration shown at the beginning of this development article).

The following code represents the entire JCRHeroComponent Java class.

package com.community.htl.core;

import com.adobe.cq.sightly.WCMUsePojo;
  
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import javax.jcr.Node; 

import com.community.htl.core.Customer; 
  
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.resource.ResourceResolver;
import org.apache.sling.api.resource.ValueMap;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
 
public class JCRHeroComponent
extends WCMUsePojo
{
 
     /** The hero text bean. */
    private List <Customer> custList = null ;  
    
    private List<Customer> lBean = null;
       
    //Inject a Service that can retrieve data from the JCR! 
     private CustomerService custService;
      
    public List<Customer> getLBean() {
        return this.lBean;
   }
    
   public void setLBean(List<Customer> items) {         
       this.lBean = items; 
   }
         
    @Override
    public void activate() throws Exception {
          
          
        String filter ="";   
        Node currentNode = getResource().adaptTo(Node.class);
         
       if(currentNode.hasProperty("jcr:Heading"))
           filter = currentNode.getProperty("./jcr:Heading").getString();
           
       //Use getSlingScriptHelper().getService() to get an instance of the CustomerService
        custService = getSlingScriptHelper().getService(CustomerService.class);
        
        //Get cust data from the AEM JCR
        custList = custService.getCustomerData("All Customers") ; 
        setLBean(custList);  
    }
  
}

Modify the Maven POM file

Add the following POM dependencies to the POM file located at C:\AdobeCQ\jcrHTL.

<dependency>
               <groupId>com.adobe.aem</groupId>
               <artifactId>uber-jar</artifactId>
               <version>6.2.0</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>

Modify the POM files to successfully build the OSGi bundle. In the POM file located at jcrHtl\core, 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"?>
<!--
 |  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>jcrHtl</groupId>
        <artifactId>jcrHtl</artifactId>
        <version>1.0-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>
    <artifactId>jcrHtl.core</artifactId>
    <packaging>bundle</packaging>
    <name>jcrHtl - Core</name>
    <description>Core bundle for jcrHtl</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.community.htl.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/jcrHtl/install to exist!!          -->
                            <!--    This is typically the case when ui.apps is deployed first                -->
                            <!--    Otherwise, create /apps/jcrHtl/install manually (CRXDE|Lite)  -->
                            <slingUrlSuffix>/apps/jcrHtl/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>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 component by using Maven, perform these steps:

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

Note:

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

Create the HTL Front End Component

When you use the Maven Archetype 10 archetype to create an AEM project, a default front end project is created, as shown in the following illustration:

HomeView
The default nodes under apps

Add HTL code

For the purpose of this article, the HTL code is written within a Maven Archetype 10 default component located here:

/apps/jcrHtl/components/content/helloworld/helloworld.html

Add the following code.

AEM JCR HTL Example: 
<div data-sly-use.v="com.community.htl.core.JCRHeroComponent">
<b>Here are the JCR Data Query results:</b>

    <ul data-sly-list="${v.lBean}"> 
		<h3>Customer Record</h3>
		 <li><b>First Name</b> - ${item.custFirst}</li>
		<li><b>Last Name</b> - ${item.custLast}</li>
        <li><b>Address</b> - ${item.custAddress}</li>
        <li><b>Description</b> - ${item.custDescription}</li>

    </ul>   
</div>

In this example, notice data-sly-use.v references the Java component: com.community.htl.core.JCRHeroComponent.

The code:

data-sly-list="${v.lBean}" maps to the data member of the JCRHeroComponent class named lBean, which is a Java List object, where each element is a Customer object.

Next notice these lines of code:

<li><b>First Name</b> - ${item.custFirst}</li>
<li><b>Last Name</b> - ${item.custLast}</li>
<li><b>Address</b> - ${item.custAddress}</li>
<li><b>Description</b> - ${item.custDescription}</li
>

This is how you write out the value stored in each Customer object in the HTL frontend. That is, 

${item.custFirst}

invokes the Customer object's getCustFirst method, which returns the value of the first data member in the Customer object. This is how you can use Java and HTL to write out the JCR content to an HTL component. 

View the output of the HTL component

To access the component, enter the following URL:

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

The following illustration shows the HTL component.

Client
An HTL component displaying JCR content

Note:

You can add more nodes under /content/customer and see them displayed in this AEM web page. 

See also

Congratulations, you have just created an AEM HTL component that queries JCR data by using JCR SQL2. 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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