src/main/java/org/apache/felix/scrplugin/tags/annotation/AnnotationTagProviderManager.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.felix.scrplugin.tags.annotation;

import java.util.ArrayList;
import java.util.List;

import org.apache.felix.scrplugin.tags.JavaField;
import org.apache.felix.scrplugin.tags.JavaTag;
import org.apache.felix.scrplugin.tags.annotation.defaulttag.DefaultAnnotationTagProvider;
import org.apache.felix.scrplugin.tags.annotation.sling.SlingAnnotationTagProvider;
import org.apache.maven.plugin.MojoFailureException;

import com.thoughtworks.qdox.model.Annotation;
import com.thoughtworks.qdox.model.JavaClass;

/**
 * Supports mapping of built-in and custom java anntoations to {@link JavaTag}
 * implementations.
 */
public class AnnotationTagProviderManager {

    /**
     * Allows to define additional implementations of the interface
     * {@link org.apache.felix.scrplugin.tags.annotation.AnnotationTagProvider}
     * that provide mappings from custom annotations to
     * {@link org.apache.felix.scrplugin.tags.JavaTag} implementations.
     */
    private final List<AnnotationTagProvider> annotationTagProviders = new ArrayList<AnnotationTagProvider>();

    /**
     * @param annotationTagProviderClasses List of classes that implements
     *            {@link AnnotationTagProvider} interface.
     * @throws MojoFailureException
     */
    public AnnotationTagProviderManager(String[] annotationTagProviderClasses) throws MojoFailureException {

        // always add provider supporting built-in SCR default properties
        annotationTagProviders.add(new DefaultAnnotationTagProvider());
        annotationTagProviders.add(new SlingAnnotationTagProvider());

        // add custom providers defined in pom
        for (int i = 0; i < annotationTagProviderClasses.length; i++) {
            try {
                Class<?> clazz = Class.forName(annotationTagProviderClasses[i]);
                try {
                    annotationTagProviders.add((AnnotationTagProvider) clazz.newInstance());
                } catch (ClassCastException e) {
                    throw new MojoFailureException("Class '" + clazz.getName() + "' "
                            + "does not implement interface '" + AnnotationTagProvider.class.getName() + "'.");
                } catch (InstantiationException e) {
                    throw new MojoFailureException("Unable to instantiate class '" + clazz.getName() + "': "
                            + e.getMessage());
                } catch (IllegalAccessException e) {
                    throw new MojoFailureException("Illegal access to class '" + clazz.getName() + "': "
                            + e.getMessage());
                }
            } catch (ClassNotFoundException ex) {
                throw new MojoFailureException("Annotation provider class '" + annotationTagProviderClasses[i]
                        + "' not found.");
            }
        }

    }

    /**
     * Converts a java annotation to {@link JavaTag} if a mapping can be found.
     *
     * @param annotation Java annotation
     * @param description Description
     * @return Tag declaration or null if no mapping found
     */
    public List<JavaTag> getTags(Annotation annotation, AnnotationJavaClassDescription description) {
        return getTags(annotation, description, null);
    }

    /**
     * Converts a java annotation to {@link JavaTag} if a mapping can be found.
     *
     * @param annotation Java annotation
     * @param description Description
     * @param field Field
     * @return Tag declaration or null if no mapping found
     */
    public List<JavaTag> getTags(Annotation annotation, AnnotationJavaClassDescription description, JavaField field) {
        List<JavaTag> tags = new ArrayList<JavaTag>();

        for (AnnotationTagProvider provider : this.annotationTagProviders) {
            tags.addAll(provider.getTags(annotation, description, field));
        }

        return tags;
    }

    /**
     * Checks if the given class has any SCR plugin java annotations defined.
     * @param pClass Class
     * @return true if SCR plugin java annotation found
     */
    public boolean hasScrPluginAnnotation(JavaClass pClass) {
        for (com.thoughtworks.qdox.model.Annotation annotation : pClass.getAnnotations()) {
            if (getTags(annotation, null).size() > 0) {
                return true;
            }
        }
        return false;
    }
}