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 */
018package org.apache.bcel;
019
020import java.io.IOException;
021
022import org.apache.bcel.classfile.JavaClass;
023import org.apache.bcel.util.ClassPath;
024import org.apache.bcel.util.SyntheticRepository;
025
026/**
027 * The repository maintains informations about class interdependencies, e.g., whether a class is a sub-class of another.
028 * Delegates actual class loading to SyntheticRepository with current class path by default.
029 *
030 * @see org.apache.bcel.util.Repository
031 * @see SyntheticRepository
032 *
033 */
034public abstract class Repository {
035
036    private static org.apache.bcel.util.Repository repository = SyntheticRepository.getInstance();
037
038    /**
039     * Adds clazz to repository if there isn't an equally named class already in there.
040     *
041     * @return old entry in repository
042     */
043    public static JavaClass addClass(final JavaClass clazz) {
044        final JavaClass old = repository.findClass(clazz.getClassName());
045        repository.storeClass(clazz);
046        return old;
047    }
048
049    /**
050     * Clears the repository.
051     */
052    public static void clearCache() {
053        repository.clear();
054    }
055
056    /**
057     * @return all interfaces implemented by class and its super classes and the interfaces that those interfaces extend,
058     *         and so on. (Some people call this a transitive hull).
059     * @throws ClassNotFoundException if any of the class's superclasses or superinterfaces can't be found
060     */
061    public static JavaClass[] getInterfaces(final JavaClass clazz) throws ClassNotFoundException {
062        return clazz.getAllInterfaces();
063    }
064
065    /**
066     * @return all interfaces implemented by class and its super classes and the interfaces that extend those interfaces,
067     *         and so on
068     * @throws ClassNotFoundException if the named class can't be found, or if any of its superclasses or superinterfaces
069     *         can't be found
070     */
071    public static JavaClass[] getInterfaces(final String className) throws ClassNotFoundException {
072        return getInterfaces(lookupClass(className));
073    }
074
075    /**
076     * @return currently used repository instance
077     */
078    public static org.apache.bcel.util.Repository getRepository() {
079        return repository;
080    }
081
082    /**
083     * @return list of super classes of clazz in ascending order, i.e., Object is always the last element
084     * @throws ClassNotFoundException if any of the superclasses can't be found
085     */
086    public static JavaClass[] getSuperClasses(final JavaClass clazz) throws ClassNotFoundException {
087        return clazz.getSuperClasses();
088    }
089
090    /**
091     * @return list of super classes of clazz in ascending order, i.e., Object is always the last element.
092     * @throws ClassNotFoundException if the named class or any of its superclasses can't be found
093     */
094    public static JavaClass[] getSuperClasses(final String className) throws ClassNotFoundException {
095        return getSuperClasses(lookupClass(className));
096    }
097
098    /**
099     * @return true, if clazz is an implementation of interface inter
100     * @throws ClassNotFoundException if any superclasses or superinterfaces of clazz can't be found
101     */
102    public static boolean implementationOf(final JavaClass clazz, final JavaClass inter) throws ClassNotFoundException {
103        return clazz.implementationOf(inter);
104    }
105
106    /**
107     * @return true, if clazz is an implementation of interface inter
108     * @throws ClassNotFoundException if inter or any superclasses or superinterfaces of clazz can't be found
109     */
110    public static boolean implementationOf(final JavaClass clazz, final String inter) throws ClassNotFoundException {
111        return implementationOf(clazz, lookupClass(inter));
112    }
113
114    /**
115     * @return true, if clazz is an implementation of interface inter
116     * @throws ClassNotFoundException if clazz or any superclasses or superinterfaces of clazz can't be found
117     */
118    public static boolean implementationOf(final String clazz, final JavaClass inter) throws ClassNotFoundException {
119        return implementationOf(lookupClass(clazz), inter);
120    }
121
122    /**
123     * @return true, if clazz is an implementation of interface inter
124     * @throws ClassNotFoundException if clazz, inter, or any superclasses or superinterfaces of clazz can't be found
125     */
126    public static boolean implementationOf(final String clazz, final String inter) throws ClassNotFoundException {
127        return implementationOf(lookupClass(clazz), lookupClass(inter));
128    }
129
130    /**
131     * Equivalent to runtime "instanceof" operator.
132     *
133     * @return true, if clazz is an instance of super_class
134     * @throws ClassNotFoundException if any superclasses or superinterfaces of clazz can't be found
135     */
136    public static boolean instanceOf(final JavaClass clazz, final JavaClass super_class) throws ClassNotFoundException {
137        return clazz.instanceOf(super_class);
138    }
139
140    /**
141     * @return true, if clazz is an instance of super_class
142     * @throws ClassNotFoundException if super_class can't be found
143     */
144    public static boolean instanceOf(final JavaClass clazz, final String super_class) throws ClassNotFoundException {
145        return instanceOf(clazz, lookupClass(super_class));
146    }
147
148    /**
149     * @return true, if clazz is an instance of super_class
150     * @throws ClassNotFoundException if clazz can't be found
151     */
152    public static boolean instanceOf(final String clazz, final JavaClass super_class) throws ClassNotFoundException {
153        return instanceOf(lookupClass(clazz), super_class);
154    }
155
156    /**
157     * @return true, if clazz is an instance of super_class
158     * @throws ClassNotFoundException if either clazz or super_class can't be found
159     */
160    public static boolean instanceOf(final String clazz, final String super_class) throws ClassNotFoundException {
161        return instanceOf(lookupClass(clazz), lookupClass(super_class));
162    }
163
164    /**
165     * Tries to find class source using the internal repository instance.
166     *
167     * @see Class
168     * @return JavaClass object for given runtime class
169     * @throws ClassNotFoundException if the class could not be found or parsed correctly
170     */
171    public static JavaClass lookupClass(final Class<?> clazz) throws ClassNotFoundException {
172        return repository.loadClass(clazz);
173    }
174
175    /**
176     * Lookups class somewhere found on your CLASSPATH, or whereever the repository instance looks for it.
177     *
178     * @return class object for given fully qualified class name
179     * @throws ClassNotFoundException if the class could not be found or parsed correctly
180     */
181    public static JavaClass lookupClass(final String className) throws ClassNotFoundException {
182        return repository.loadClass(className);
183    }
184
185    /**
186     * @return class file object for given Java class by looking on the system class path; returns null if the class file
187     *         can't be found
188     */
189    public static ClassPath.ClassFile lookupClassFile(final String className) {
190        try (final ClassPath path = repository.getClassPath()) {
191            if (path == null) {
192                return null;
193            }
194            return path.getClassFile(className);
195        } catch (final IOException e) {
196            return null;
197        }
198    }
199
200    /**
201     * Removes given class from repository.
202     */
203    public static void removeClass(final JavaClass clazz) {
204        repository.removeClass(clazz);
205    }
206
207    /**
208     * Removes class with given (fully qualified) name from repository.
209     */
210    public static void removeClass(final String clazz) {
211        repository.removeClass(repository.findClass(clazz));
212    }
213
214    /**
215     * Sets repository instance to be used for class loading
216     */
217    public static void setRepository(final org.apache.bcel.util.Repository rep) {
218        repository = rep;
219    }
220}