Spring Framework example source code file (AnnotationMetadataReadingVisitor.java)

This example Spring Framework source code file (AnnotationMetadataReadingVisitor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

annotation, annotation, annotationmetadata, annotationvisitor, hashset, linkedhashmap, map, map, method, object, object, reflection, set, set, string, string, util

The Spring Framework AnnotationMetadataReadingVisitor.java source code

/*
 * Copyright 2002-2008 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.core.type.classreading;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;

import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.Type;
import org.objectweb.asm.commons.EmptyVisitor;

import org.springframework.core.type.AnnotationMetadata;

/**
 * ASM class visitor which looks for the class name and implemented types as
 * well as for the annotations defined on the class, exposing them through
 * the {@link org.springframework.core.type.AnnotationMetadata} interface.
 *
 * @author Juergen Hoeller
 * @author Mark Fisher
 * @since 2.5
 */
class AnnotationMetadataReadingVisitor extends ClassMetadataReadingVisitor implements AnnotationMetadata {

	private final Map<String, Map attributesMap = new LinkedHashMap>();

	private final Map<String, Set metaAnnotationMap = new LinkedHashMap>();


	public AnnotationVisitor visitAnnotation(final String desc, boolean visible) {
		final String className = Type.getType(desc).getClassName();
		final Map<String, Object> attributes = new LinkedHashMap();
		return new EmptyVisitor() {
			public void visit(String name, Object value) {
				// Explicitly defined annotation attribute value.
				attributes.put(name, value);
			}
			public void visitEnd() {
				try {
					Class annotationClass = getClass().getClassLoader().loadClass(className);
					// Check declared default values of attributes in the annotation type.
					Method[] annotationAttributes = annotationClass.getMethods();
					for (int i = 0; i < annotationAttributes.length; i++) {
						Method annotationAttribute = annotationAttributes[i];
						String attributeName = annotationAttribute.getName();
						Object defaultValue = annotationAttribute.getDefaultValue();
						if (defaultValue != null && !attributes.containsKey(attributeName)) {
							attributes.put(attributeName, defaultValue);
						}
					}
					// Register annotations that the annotation type is annotated with.
					Annotation[] metaAnnotations = annotationClass.getAnnotations();
					Set<String> metaAnnotationTypeNames = new HashSet();
					for (Annotation metaAnnotation : metaAnnotations) {
						metaAnnotationTypeNames.add(metaAnnotation.annotationType().getName());
					}
					metaAnnotationMap.put(className, metaAnnotationTypeNames);
				}
				catch (ClassNotFoundException ex) {
					// Class not found - can't determine meta-annotations.
				}
				attributesMap.put(className, attributes);
			}
		};
	}


	public Set<String> getAnnotationTypes() {
		return this.attributesMap.keySet();
	}

	public boolean hasAnnotation(String annotationType) {
		return this.attributesMap.containsKey(annotationType);
	}

	public Set<String> getMetaAnnotationTypes(String annotationType) {
		return this.metaAnnotationMap.get(annotationType);
	}

	public boolean hasMetaAnnotation(String metaAnnotationType) {
		Collection<Set allMetaTypes = this.metaAnnotationMap.values();
		for (Set<String> metaTypes : allMetaTypes) {
			if (metaTypes.contains(metaAnnotationType)) {
				return true;
			}
		}
		return false;
	}

	public Map<String, Object> getAnnotationAttributes(String annotationType) {
		return this.attributesMap.get(annotationType);
	}

}