How to Create Custom Adapters in Adobe CQ / AEM

Prerequisite: http://sling.apache.org/documentation/the-sling-engine/adapters.html

Use Case: You often have a case where you want to adaptTo from existing object to custom Object or Provide adapter functionality for custom object to existing object.

Solution: There are mainly two ways you can use adaptTo

Case 1: You want existing object to be adaptable to custom object. For example you have a specific kind of node and you want Node or Resource to be adaptable to this object.

CustomObject myCustomObject   = resource.adaptTo(CustomObject.class)
Or
CustomObject myCustomObject   = node.adaptTo(CustomObject.class)
Or
CustomObject myCustomObject   = <ANY Adaptable OBJECT>.adaptTo(CustomObject.class)

Case 2: You want custom object to be adaptable to existing object. For example you have specific kind of resource and you want this to be adaptable to existing resource.

Node node = CustomObject.adaptTo(Node.class)
Or
Resource resource = CustomObject.adaptTo(Resource.class)
Or
<Any OOTB Adaptable> myObject   = MycustomObject.adaptTo(<Any OOTB Adaptable>.class)

Case 1: Example

Here is how your CustomAdapter will look like

Case 2: Example

for this you can use slingAdaptable class https://dev.day.com/docs/en/cq/5-6/javadoc/org/apache/sling/api/adapter/SlingAdaptable.html

One example (You can find more example here) http://svn.apache.org/repos/asf/sling/trunk/bundles/resourceresolver/src/main/java/org/apache/sling/resourceresolver/impl/ResourceResolverImpl.java

In pom.xml you need following include. You can always find dependencies from HOST:PORT/system/console/depfinder

<dependency>

    <groupId>org.apache.sling</groupId>

    <artifactId>org.apache.sling.api</artifactId>

    <version>2.2.4</version>

    <scope>provided</scope>

</dependency>

<dependency>

      <groupId>org.apache.sling</groupId>

       <artifactId>org.apache.sling.adapter</artifactId>

        <version>2.0.10</version>

        <scope>provided</scope>

</dependency>

Let me know if you have any question.