Short Answer
In Adobe Experience Manager (AEM), the ResourceResolver is an API that acts as a service for resolving resources. It maps URLs to content nodes and provides an interface to access or manipulate the content stored in the repository.
Overview of ResourceResolver
Function of ResourceResolver
The ResourceResolver is one of the core concepts in AEM and is essential for:
- Mapping HTTP requests to the correct repository node.
- Reading and modifying content.
- Querying the repository.
- Adapting resources to other types, such as Page or Asset.
How ResourceResolver Works
The ResourceResolver can be thought of as a tool that translates between the AEM content repository structure and the HTTP request space. It does this by:
- Interpreting URLs and paths to find the corresponding node in the JCR (Java Content Repository).
- Providing methods to access and manipulate these nodes.
Using ResourceResolver
Obtaining a ResourceResolver
To work with ResourceResolver, you typically need to obtain an instance through the ResourceResolverFactory. This is done by:
- Injecting ResourceResolverFactory: Use OSGi annotations to inject ResourceResolverFactory into your service or servlet.
- Creating a Map of Authentication Details: Construct a map to pass authentication details if needed.
- Getting ResourceResolver: Call the getResourceResolver method of the ResourceResolverFactory with the authentication map to obtain a ResourceResolver.
Common Operations with ResourceResolver
With a ResourceResolver instance, you can perform operations like:
- Resolving a Resource: Call resolve with a path or URL to get the corresponding Resource.
- Creating a Resource: Use create to add a new resource to the repository.
- Adapting to Other Types: Use adaptTo to convert a Resource to another type for specific operations.
- Deleting a Resource: Obtain a resource and then call delete to remove it from the repository.
- Querying: Execute queries against the repository to retrieve resources based on specific criteria.
Example of Using ResourceResolver
Here’s a simplified example of how to obtain and use a ResourceResolver:
// Inject the ResourceResolverFactory
@Reference
private ResourceResolverFactory resolverFactory;
public void someMethod() {
ResourceResolver resolver = null;
try {
// Create an authentication map (if required)
Map<String, Object> authInfo = new HashMap<>();
authInfo.put(ResourceResolverFactory.SUBSERVICE, "someService");
// Obtain the ResourceResolver
resolver = resolverFactory.getServiceResourceResolver(authInfo);
// Now use the ResourceResolver to resolve a resource
Resource resource = resolver.resolve("/content/myPage");
// Perform operations with the resource...
} catch (LoginException e) {
// Handle login exception
} finally {
if (resolver != null) {
resolver.close();
}
}
}Best Practices
When working with ResourceResolver, it is important to:
- Close the ResourceResolver: Always close the ResourceResolver which you’ve opened after use to avoid memory leaks and resource exhaustion.
- Use Try-With-Resources: If you are using Java 7 or above, you can use try-with-resources for automatic closing.
- Handle Security Correctly: Ensure that service users have the correct permissions and are used securely.
Conclusion
The ResourceResolver in AEM is a crucial API for developers, allowing them to access and manage content resources easily. It provides a bridge between the HTTP world and the JCR content nodes, supporting various operations required for web content management. Proper management and usage of the ResourceResolver are vital in developing efficient, secure, and robust AEM applications.
