001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.camel.blueprint;
018
019import java.lang.reflect.Modifier;
020import java.util.List;
021import java.util.Set;
022
023import org.apache.camel.RoutesBuilder;
024import org.apache.camel.spi.PackageScanClassResolver;
025import org.osgi.service.blueprint.container.BlueprintContainer;
026import org.osgi.service.blueprint.reflect.BeanMetadata;
027import org.slf4j.Logger;
028import org.slf4j.LoggerFactory;
029
030/**
031 * A helper class which will find all {@link org.apache.camel.builder.RouteBuilder} instances on the classpath
032 *
033 * @version 
034 */
035public class PackageScanRouteBuilderFinder {
036    private static final Logger LOG = LoggerFactory.getLogger(PackageScanRouteBuilderFinder.class);
037    private final BlueprintCamelContext camelContext;
038    private final String[] packages;
039    private final PackageScanClassResolver resolver;
040    private final BlueprintContainer blueprintContainer;
041
042    public PackageScanRouteBuilderFinder(BlueprintCamelContext camelContext, String[] packages, ClassLoader classLoader,
043                                         PackageScanClassResolver resolver) {
044        this.camelContext = camelContext;
045        this.blueprintContainer = camelContext.getBlueprintContainer();
046        this.packages = packages;
047        this.resolver = resolver;
048        // add our provided loader as well
049        resolver.addClassLoader(classLoader);
050    }
051
052    /**
053     * Appends all the {@link org.apache.camel.builder.RouteBuilder} instances that can be found on the classpath
054     */
055    public void appendBuilders(List<RoutesBuilder> list) throws IllegalAccessException, InstantiationException {
056        Set<Class<?>> classes = resolver.findImplementations(RoutesBuilder.class, packages);
057        for (Class<?> aClass : classes) {
058            LOG.trace("Found RouteBuilder class: {}", aClass);
059
060            // certain beans should be ignored
061            if (shouldIgnoreBean(aClass)) {
062                LOG.debug("Ignoring RouteBuilder class: {}", aClass);
063                continue;
064            }
065
066            if (!isValidClass(aClass)) {
067                LOG.debug("Ignoring invalid RouteBuilder class: {}", aClass);
068                continue;
069            }
070
071            // type is valid so create and instantiate the builder
072            RoutesBuilder builder = instantiateBuilder(aClass);
073            LOG.debug("Adding instantiated RouteBuilder: {}", builder);
074            list.add(builder);
075        }
076    }
077
078    /**
079     * Allows for ignoring beans that are explicitly configured in the Spring XML files
080     */
081    protected boolean shouldIgnoreBean(Class<?> type) {
082        for (Object metadataObject : blueprintContainer.getMetadata(BeanMetadata.class)) {
083            BeanMetadata metadata = (BeanMetadata) metadataObject;
084            if (BeanMetadata.SCOPE_SINGLETON.equals(metadata.getScope())) {
085                Object bean = blueprintContainer.getComponentInstance(metadata.getId());
086                if (type.isInstance(bean)) {
087                    return true;
088                }
089            }
090        }
091        return false;
092    }
093
094    /**
095     * Returns <tt>true</tt>if the class is a public, non-abstract class
096     */
097    protected boolean isValidClass(Class<?> type) {
098        // should skip non public classes
099        if (!Modifier.isPublic(type.getModifiers())) {
100            return false;
101        }
102
103        if (!Modifier.isAbstract(type.getModifiers()) && !type.isInterface()) {
104            return true;
105        }
106        return false;
107    }
108
109    protected RoutesBuilder instantiateBuilder(Class<?> type) throws IllegalAccessException, InstantiationException {
110        return (RoutesBuilder) camelContext.getInjector().newInstance(type);
111    }
112}