Service Provider Interface (SPI)

/**
 * Exposes elements of a module so they can be inspected, validated or rewritten.
 * Elements are extractable from modules and can be used to build new modules.
 */
public final class Elements {
    /**
     * Records the elements executed by modules so they can be analyzed.
     * @param modules Modules to extract elements from
     * @return List of elements from the modules
     */
    public static List<Element> getElements(Module... modules);
    
    /**
     * Records the elements executed by modules so they can be analyzed.
     * @param stage Development stage
     * @param modules Modules to extract elements from
     * @return List of elements from the modules
     */
    public static List<Element> getElements(Stage stage, Iterable<? extends Module> modules);
    
    /**
     * Creates a module from the given elements.
     * @param elements Elements to build module from
     * @return Module containing the elements
     */
    public static Module getModule(Iterable<? extends Element> elements);
}

/**
 * A core component of a module or injector. Elements are extractable from modules
 * and can be inspected, validated or rewritten.
 */
public interface Element {
    /**
     * Returns the source object which was used to create this element.
     * @return Source object
     */
    Object getSource();
    
    /**
     * Accepts a visitor for this element.
     * @param visitor Element visitor
     * @return Result from visitor
     */
    <T> T acceptVisitor(ElementVisitor<T> visitor);
    
    /**
     * Writes this element to the given binder.
     * @param binder Binder to write to
     */
    void applyTo(Binder binder);
}

// Extract elements from modules for analysis
public class ModuleAnalyzer {
    public void analyzeModule(Module module) {
        List<Element> elements = Elements.getElements(module);
        
        for (Element element : elements) {
            element.acceptVisitor(new DefaultElementVisitor<Void>() {
                @Override
                public <T> Void visit(Binding<T> binding) {
                    System.out.println("Found binding: " + binding.getKey());
                    return null;
                }
                
                @Override
                public Void visit(PrivateElements privateElements) {
                    System.out.println("Found private module with " + 
                        privateElements.getElements().size() + " elements");
                    return null;
                }
            });
        }
    }
}

// Rewrite modules
public Module rewriteModule(Module originalModule) {
    List<Element> elements = Elements.getElements(originalModule);
    
    // Filter or transform elements as needed
    List<Element> filteredElements = elements.stream()
        .filter(element -> shouldIncludeElement(element))
        .collect(Collectors.toList());
    
    return Elements.getModule(filteredElements);
}