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     */
017    package org.apache.camel.blueprint;
018    
019    import java.lang.reflect.Modifier;
020    import java.util.List;
021    import java.util.Set;
022    
023    import org.apache.camel.RoutesBuilder;
024    import org.apache.camel.spi.PackageScanClassResolver;
025    import org.osgi.service.blueprint.container.BlueprintContainer;
026    import org.osgi.service.blueprint.reflect.BeanMetadata;
027    import org.slf4j.Logger;
028    import 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     */
035    public class PackageScanRouteBuilderFinder {
036        private static final transient 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    }