001/*
002 * (C) Copyright 2006-2011 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     bstefanescu
018 */
019package org.nuxeo.runtime.test.runner;
020
021import java.lang.annotation.Annotation;
022import java.lang.annotation.Inherited;
023import java.util.ArrayList;
024import java.util.Arrays;
025import java.util.HashSet;
026import java.util.Hashtable;
027import java.util.List;
028import java.util.Map;
029import java.util.Set;
030
031import com.google.common.base.Predicates;
032import com.google.common.collect.ImmutableList;
033import com.google.common.collect.Iterables;
034
035import io.github.lukehutch.fastclasspathscanner.FastClasspathScanner;
036
037/**
038 * @author <a href="mailto:[email protected]">Bogdan Stefanescu</a>
039 */
040public class AnnotationScanner {
041
042    protected final Set<Class<?>> visitedClasses = new HashSet<Class<?>>();
043
044    protected final Map<Class<?>, List<Annotation>> classes = new Hashtable<Class<?>, List<Annotation>>();
045
046    public synchronized void scan(Class<?> clazz) {
047        if (classes.containsKey(clazz)) {
048            return;
049        }
050        collectAnnotations(clazz);
051    }
052
053    public List<? extends Annotation> getAnnotations(Class<?> clazz) {
054        if (!visitedClasses.contains(clazz)) {
055            scan(clazz);
056        }
057        return classes.get(clazz);
058    }
059
060    public <T extends Annotation> T getAnnotation(Class<?> clazz, Class<T> annotationType) {
061        final List<T> annotations = getAnnotations(clazz, annotationType);
062        if (annotations.isEmpty()) {
063            return null;
064        }
065        return Defaults.of(annotationType, annotations);
066    }
067
068    public <T extends Annotation> T getFirstAnnotation(Class<?> clazz, Class<T> annotationType) {
069        List<T> result = getAnnotations(clazz, annotationType);
070        if (result.isEmpty()) {
071            return null;
072        }
073        return result.get(0);
074    }
075
076    @SuppressWarnings("unchecked")
077    public <T extends Annotation> List<T> getAnnotations(Class<?> clazz, Class<T> annotationType) {
078        if (!visitedClasses.contains(clazz)) {
079            scan(clazz);
080        }
081        return (List<T>) ImmutableList.copyOf(Iterables.filter(classes.get(clazz),
082                Predicates.instanceOf(annotationType)));
083    }
084
085    /**
086     * TODO when collecting annotations annotated with {@link Inherited} they will be collected twice.
087     *
088     * @param clazz
089     * @param result
090     * @param visitedClasses
091     */
092    protected List<Annotation> collectAnnotations(Class<?> clazz) {
093        if (visitedClasses.contains(clazz)) {
094            return classes.get(clazz);
095        }
096        visitedClasses.add(clazz);
097        List<Annotation> result = new ArrayList<Annotation>(); // collect only the annotation on this class
098        try {
099            Annotation[] data = clazz.getAnnotations();
100            result.addAll(Arrays.asList(data));
101        } catch (ArrayStoreException cause) {
102            throw new AssertionError(
103                    "Cannot load annotations of " + clazz.getName() + ", check your classpath for missing classes\n" + new FastClasspathScanner().getUniqueClasspathElements(),
104                    cause);
105        }
106        // first scan interfaces
107        for (Class<?> itf : clazz.getInterfaces()) {
108            result.addAll(collectAnnotations(itf));
109        }
110        // collect annotations from super classes
111        Class<?> superClass = clazz.getSuperclass();
112        if (superClass != null) {
113            result.addAll(collectAnnotations(superClass));
114        }
115        classes.put(clazz, result);
116        return result;
117    }
118
119}