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.spi;
018    
019    import java.lang.annotation.Annotation;
020    import java.util.Set;
021    
022    /**
023     * A resolver that can find resources based on package scanning.
024     */
025    public interface PackageScanClassResolver {
026    
027        /**
028         * Sets the ClassLoader instances that should be used when scanning for
029         * classes. If none is set then the context classloader will be used.
030         *
031         * @param classLoaders loaders to use when scanning for classes
032         * @deprecated will be removed in Camel 3.0. Use {@link #addClassLoader(ClassLoader)} instead.
033         */
034        @Deprecated
035        void setClassLoaders(Set<ClassLoader> classLoaders);
036    
037        /**
038         * Gets the ClassLoader instances that should be used when scanning for classes.
039         * <p/>
040         * This implementation will return a new unmodifiable set containing the classloaders.
041         * Use the {@link #addClassLoader(ClassLoader)} method if you want to add new classloaders
042         * to the class loaders list.
043         *
044         * @return the class loaders to use
045         */
046        Set<ClassLoader> getClassLoaders();
047    
048        /**
049         * Adds the class loader to the existing loaders
050         *
051         * @param classLoader the loader to add
052         */
053        void addClassLoader(ClassLoader classLoader);
054    
055        /**
056         * Attempts to discover classes that are annotated with to the annotation.
057         *
058         * @param annotation   the annotation that should be present on matching classes
059         * @param packageNames one or more package names to scan (including subpackages) for classes
060         * @return the classes found, returns an empty set if none found
061         */
062        Set<Class<?>> findAnnotated(Class<? extends Annotation> annotation, String... packageNames);
063    
064        /**
065         * Attempts to discover classes that are annotated with to the annotation.
066         *
067         * @param annotations   the annotations that should be present (any of them) on matching classes
068         * @param packageNames one or more package names to scan (including subpackages) for classes
069         * @return the classes found, returns an empty set if none found
070         */
071        Set<Class<?>> findAnnotated(Set<Class<? extends Annotation>> annotations, String... packageNames);
072    
073        /**
074         * Attempts to discover classes that are assignable to the type provided. In
075         * the case that an interface is provided this method will collect
076         * implementations. In the case of a non-interface class, subclasses will be
077         * collected.
078         *
079         * @param parent       the class of interface to find subclasses or implementations of
080         * @param packageNames one or more package names to scan (including subpackages) for classes
081         * @return the classes found, returns an empty set if none found
082         */
083        Set<Class<?>> findImplementations(Class<?> parent, String... packageNames);
084    
085        /**
086         * Attempts to discover classes filter by the provided filter
087         *
088         * @param filter  filter to filter desired classes.
089         * @param packageNames one or more package names to scan (including subpackages) for classes
090         * @return the classes found, returns an empty set if none found
091         */
092        Set<Class<?>> findByFilter(PackageScanFilter filter, String... packageNames);
093        
094        /**
095         * Add a filter that will be applied to all scan operations
096         * 
097         * @param filter filter to filter desired classes in all scan operations
098         */
099        void addFilter(PackageScanFilter filter);
100    
101        /**
102         * Removes the filter
103         *
104         * @param filter filter to filter desired classes in all scan operations
105         */
106        void removeFilter(PackageScanFilter filter);
107    }