Architecture

AEM architecture

Java Content Repository (JCR)

• Standard API to access data (separate from underlying implementation)
• Hierarchical Database that looks like a file system, Data represented in Tree structure
• Supports mechanisms like querying, full text search, permissions, transactions, versioning, event management and more
• Supports structured and unstructured content
• One of the implementation: Apache Jackrabbit Oak
• Supports file system features like: hierarchy, locking, access control, binaries

JCR visualized in CRX:

Example properties:

• jcr:primaryType- basic information about the node, determine some required properties that a node have
• jcr:mixinTypes - additional property that extend functionality of primary type, similar to interface in java

Sling

• RESTful framework for web applications based on content repository (JCR) - provides REST API for JCR-based applications
• Resource oriented - most resources maps to JCR nodes
• Sling decomposes the URL, resolves the resource to be rendered from the path, locates the script to render the resource and then renders the requested resource

** Sling script resolution diagram **

Documentation

• Sling URL decomposition