Apache Sling Engine Implementation

This module is part of the Apache Sling project and implements the core Sling request processing pipeline.

Overview

org.apache.sling.engine provides the Sling engine bundle that:

• registers the main servlet via OSGi HTTP Whiteboard
• resolves resources and dispatches requests
• manages Sling filter chains and request/response wrapping
• exposes request processor and filter processor metrics via JMX
• supports both javax.servlet (legacy) and jakarta.servlet through adapter classes

Requirements

• Java 17
• Maven

Build and test

# Build and package (skip tests)
mvn clean install -DskipTests

# Full build with tests
mvn clean install

# Run all tests
mvn test

# Run a single test class
mvn test -Dtest=SlingRequestPathInfoTest

# Run tests with a name pattern
mvn test -Dtest="*FilterChain*"

# License header check (Apache RAT)
mvn apache-rat:check

# Check formatting (Spotless, inherited from parent POM)
mvn spotless:check

# Apply formatting
mvn spotless:apply

# Run Japex microbenchmarks
mvn test -Pbenchmarks

Repository layout

pom.xml                          Maven build descriptor
bnd.bnd                          OSGi bundle manifest instructions
src/
  main/java/org/apache/sling/engine/
    *.java                       Public API
    impl/                        Internal implementation
      adapter/                   javax <-> jakarta servlet adapters
      console/                   Web Console plugins
      debug/                     RequestProgressTracker integration
      filter/                    Sling filter chain management
      helper/                    Servlet context/request listener helpers
      log/                       Request logging support
      parameters/                Request parameter and multipart handling
      request/                   Request data and dispatching
    jmx/                         JMX MBean interfaces
    servlets/                    Error handler servlet API
  test/java/                     Unit tests
  test/resources/japex/          Benchmark configurations

Notes

• OSGi Declarative Services annotations are used (org.osgi.service.component.annotations).
• The bundle imports javax.servlet with a compatibility range and supports Jakarta Servlet API in parallel.