Java tutorial
/** * 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.camel.blueprint; import java.lang.reflect.Modifier; import java.util.List; import java.util.Set; import org.apache.camel.RoutesBuilder; import org.apache.camel.spi.PackageScanClassResolver; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.osgi.service.blueprint.container.BlueprintContainer; import org.osgi.service.blueprint.reflect.BeanMetadata; /** * A helper class which will find all {@link org.apache.camel.builder.RouteBuilder} instances on the classpath * * @version $Revision$ */ public class PackageScanRouteBuilderFinder { private static final transient Log LOG = LogFactory.getLog(PackageScanRouteBuilderFinder.class); private final BlueprintCamelContext camelContext; private final String[] packages; private final PackageScanClassResolver resolver; private final BlueprintContainer blueprintContainer; // private final BeanPostProcessor beanPostProcessor; public PackageScanRouteBuilderFinder(BlueprintCamelContext camelContext, String[] packages, ClassLoader classLoader, /*BeanPostProcessor postProcessor,*/ PackageScanClassResolver resolver) { this.camelContext = camelContext; this.blueprintContainer = camelContext.getBlueprintContainer(); this.packages = packages; // this.beanPostProcessor = postProcessor; this.resolver = resolver; // add our provided loader as well resolver.addClassLoader(classLoader); } /** * Appends all the {@link org.apache.camel.builder.RouteBuilder} instances that can be found on the classpath */ public void appendBuilders(List<RoutesBuilder> list) throws IllegalAccessException, InstantiationException { Set<Class<?>> classes = resolver.findImplementations(RoutesBuilder.class, packages); for (Class aClass : classes) { if (LOG.isTraceEnabled()) { LOG.trace("Found RouteBuilder class: " + aClass); } // certain beans should be ignored if (shouldIgnoreBean(aClass)) { if (LOG.isDebugEnabled()) { LOG.debug("Ignoring RouteBuilder class: " + aClass); } continue; } if (!isValidClass(aClass)) { if (LOG.isDebugEnabled()) { LOG.debug("Ignoring invalid RouteBuilder class: " + aClass); } continue; } // type is valid so create and instantiate the builder RoutesBuilder builder = instantiateBuilder(aClass); // if (beanPostProcessor != null) { // Inject the annotated resource // beanPostProcessor.postProcessBeforeInitialization(builder, builder.toString()); // } if (LOG.isDebugEnabled()) { LOG.debug("Adding instantiated RouteBuilder: " + builder); } list.add(builder); } } /** * Lets ignore beans that are explicitly configured in the Spring XML files */ protected boolean shouldIgnoreBean(Class<?> type) { for (BeanMetadata metadata : blueprintContainer.getMetadata(BeanMetadata.class)) { if (BeanMetadata.SCOPE_SINGLETON.equals(metadata.getScope())) { Object bean = blueprintContainer.getComponentInstance(metadata.getId()); if (type.isInstance(bean)) { return true; } } } return false; } /** * Returns true if the object is non-abstract and supports a zero argument constructor */ protected boolean isValidClass(Class type) { if (!Modifier.isAbstract(type.getModifiers()) && !type.isInterface()) { return true; } return false; } @SuppressWarnings("unchecked") protected RoutesBuilder instantiateBuilder(Class type) throws IllegalAccessException, InstantiationException { return (RoutesBuilder) camelContext.getInjector().newInstance(type); } }