SJSASFactory.java

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package com.sun.enterprise.deployment.annotation.factory;

import org.glassfish.apf.AnnotationHandler;
import org.glassfish.apf.AnnotationInfo;
import org.glassfish.apf.AnnotationProcessor;
import org.glassfish.apf.AnnotationProcessorException;
import org.glassfish.apf.HandlerProcessingResult;
import org.glassfish.apf.factory.Factory;
import org.glassfish.apf.impl.AnnotationProcessorImpl;
import org.glassfish.hk2.api.ActiveDescriptor;
import org.glassfish.hk2.api.ServiceLocator;
import org.glassfish.hk2.utilities.BuilderHelper;
import org.jvnet.hk2.annotations.Service;

import javax.annotation.PostConstruct;
import javax.inject.Inject;
import javax.inject.Singleton;

import java.lang.annotation.Annotation;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * This factory is responsible for initializing a ready to use
 * AnnotationProcessor. 
 *
 * @author Shing Wai Chan
 */
@Service
@Singleton
public class SJSASFactory extends Factory {

    @Inject
    private ServiceLocator locator;

    private Set<String> annotationClassNames = new HashSet<String>();

    private AnnotationProcessorImpl systemProcessor=null;

    public AnnotationProcessor getAnnotationProcessor() {
        AnnotationProcessorImpl processor =
            Factory.getDefaultAnnotationProcessor();
        processor.setDelegate(systemProcessor);
        return processor;
    }

    @SuppressWarnings("unchecked")
    public Set<String> getAnnotations() {
        return (HashSet<String>)((HashSet<String>)annotationClassNames).clone();
    }
    
    private static String getAnnotationHandlerForStringValue(ActiveDescriptor<AnnotationHandler> onMe) {
        Map<String, List<String>> metadata = onMe.getMetadata();
        List<String> answers = metadata.get(AnnotationHandler.ANNOTATION_HANDLER_METADATA);
        if (answers == null || answers.isEmpty()) return null;
        
        return answers.get(0);
    }

    @SuppressWarnings({ "unused", "unchecked" })
    @PostConstruct
    private void postConstruct() {
        if (systemProcessor != null) return;
        
        // initialize our system annotation processor...            
        systemProcessor = new AnnotationProcessorImpl();
        for (ActiveDescriptor<?> i : locator.getDescriptors(BuilderHelper.createContractFilter(
                AnnotationHandler.class.getName()))) {
            ActiveDescriptor<AnnotationHandler> descriptor = (ActiveDescriptor<AnnotationHandler>) i;
            
            String annotationTypeName = getAnnotationHandlerForStringValue(descriptor);
            if (annotationTypeName == null) continue;
                
            systemProcessor.pushAnnotationHandler(annotationTypeName, new LazyAnnotationHandler(descriptor)); 
            annotationClassNames.add("L" +
                    annotationTypeName.
                    replace('.', '/') + ";");
        }
        
        
    }
    
    private class LazyAnnotationHandler implements AnnotationHandler {
        private final ActiveDescriptor<AnnotationHandler> descriptor;
        private AnnotationHandler handler;
        
        private LazyAnnotationHandler(ActiveDescriptor<AnnotationHandler> descriptor) {
            this.descriptor = descriptor;
        }
        
        private AnnotationHandler getHandler() {
            if (handler != null) return handler;
            
            handler = locator.getServiceHandle(descriptor).getService();
            return handler;
        }

        @Override
        public Class<? extends Annotation> getAnnotationType() {
            return getHandler().getAnnotationType();
        }

        @Override
        public HandlerProcessingResult processAnnotation(
                AnnotationInfo element) throws AnnotationProcessorException {
            return getHandler().processAnnotation(element);
        }

        @Override
        public Class<? extends Annotation>[] getTypeDependencies() {
            return getHandler().getTypeDependencies();
        }
        
    }
}