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.impl;
018
019import java.io.BufferedInputStream;
020import java.io.IOException;
021import java.io.InputStream;
022import java.util.ArrayList;
023import java.util.Collections;
024import java.util.List;
025import java.util.Properties;
026import java.util.concurrent.ConcurrentHashMap;
027import java.util.concurrent.ConcurrentMap;
028import java.util.function.Function;
029
030import org.apache.camel.NoFactoryAvailableException;
031import org.apache.camel.spi.ClassResolver;
032import org.apache.camel.spi.FactoryFinder;
033import org.apache.camel.spi.Injector;
034import org.apache.camel.util.CastUtils;
035import org.apache.camel.util.IOHelper;
036
037/**
038 * Default factory finder.
039 */
040public class DefaultFactoryFinder implements FactoryFinder {
041
042    private final ConcurrentMap<String, Class<?>> classMap = new ConcurrentHashMap<>();
043    private final ConcurrentMap<String, Boolean> classesNotFound = new ConcurrentHashMap<>();
044    private final ConcurrentMap<String, Exception> classesNotFoundExceptions = new ConcurrentHashMap<>();
045    private final ClassResolver classResolver;
046    private final String path;
047
048    public DefaultFactoryFinder(ClassResolver classResolver, String resourcePath) {
049        this.classResolver = classResolver;
050        this.path = resourcePath;
051    }
052
053    @Override
054    public String getResourcePath() {
055        return path;
056    }
057
058    @Override
059    public Object newInstance(String key) throws NoFactoryAvailableException {
060        try {
061            return newInstance(key, null);
062        } catch (Exception e) {
063            throw new NoFactoryAvailableException(key, e);
064        }
065    }
066
067    @Override
068    public <T> List<T> newInstances(String key, Injector injector, Class<T> type) throws ClassNotFoundException, IOException {
069        List<Class<T>> list = CastUtils.cast(findClasses(key));
070        List<T> answer = new ArrayList<>(list.size());
071        answer.add(newInstance(key, injector, type));
072        return answer;
073    }
074
075    @Override
076    public Class<?> findClass(String key) throws ClassNotFoundException, IOException {
077        return findClass(key, null);
078    }
079
080    @Override
081    public Class<?> findClass(String key, String propertyPrefix) throws ClassNotFoundException, IOException {
082        final String prefix = propertyPrefix != null ? propertyPrefix : "";
083        final String classKey = prefix + key;
084
085        return addToClassMap(classKey, new ClassSupplier() {
086            @Override
087            public Class<?> get() throws ClassNotFoundException, IOException {
088                return DefaultFactoryFinder.this.newInstance(DefaultFactoryFinder.this.doFindFactoryProperties(key), prefix);
089            }
090        });
091    }
092
093    @Override
094    public Class<?> findClass(String key, String propertyPrefix, Class<?> clazz) throws ClassNotFoundException, IOException {
095        // Just ignore clazz which is only useful for OSGiFactoryFinder
096        return findClass(key, propertyPrefix);
097    }
098
099    private Object newInstance(String key, String propertyPrefix) throws IllegalAccessException,
100        InstantiationException, IOException, ClassNotFoundException {
101        Class<?> clazz = findClass(key, propertyPrefix);
102        return clazz.newInstance();
103    }
104
105    private <T> T newInstance(String key, Injector injector, Class<T> expectedType) throws IOException,
106        ClassNotFoundException {
107        return newInstance(key, injector, null, expectedType);
108    }
109
110    private <T> T newInstance(String key, Injector injector, String propertyPrefix, Class<T> expectedType)
111        throws IOException, ClassNotFoundException {
112        Class<?> type = findClass(key, propertyPrefix);
113        Object value = injector.newInstance(type);
114        if (expectedType.isInstance(value)) {
115            return expectedType.cast(value);
116        } else {
117            throw new ClassCastException("Not instanceof " + expectedType.getName() + " value: " + value);
118        }
119    }
120
121    private List<Class<?>> findClasses(String key) throws ClassNotFoundException, IOException {
122        return findClasses(key, null);
123    }
124
125    private List<Class<?>> findClasses(String key, String propertyPrefix) throws ClassNotFoundException, IOException {
126        Class<?> type = findClass(key, propertyPrefix);
127        return Collections.<Class<?>>singletonList(type);
128    }
129
130    private Class<?> newInstance(Properties properties, String propertyPrefix) throws ClassNotFoundException, IOException {
131        String className = properties.getProperty(propertyPrefix + "class");
132        if (className == null) {
133            throw new IOException("Expected property is missing: " + propertyPrefix + "class");
134        }
135
136        Class<?> clazz = classResolver.resolveClass(className);
137        if (clazz == null) {
138            throw new ClassNotFoundException(className);
139        }
140        return clazz;
141    }
142
143    private Properties doFindFactoryProperties(String key) throws IOException {
144        String uri = path + key;
145
146        InputStream in = classResolver.loadResourceAsStream(uri);
147        if (in == null) {
148            throw new NoFactoryAvailableException(uri);
149        }
150
151        // lets load the file
152        BufferedInputStream reader = null;
153        try {
154            reader = IOHelper.buffered(in);
155            Properties properties = new Properties();
156            properties.load(reader);
157            return properties;
158        } finally {
159            IOHelper.close(reader, key, null);
160            IOHelper.close(in, key, null);
161        }
162    }
163
164    /*
165     * This is a wrapper function to deal with exceptions in lambdas: the exception
166     * is wrapped by a runtime exception (WrappedRuntimeException) which we catch
167     * later on with the only purpose to re-throw the original exception.
168     */
169    protected Class<?> addToClassMap(String key, ClassSupplier mappingFunction) throws ClassNotFoundException, IOException {
170        try {
171            if (classesNotFoundExceptions.containsKey(key) || classesNotFound.containsKey(key)) {
172                Exception e = classesNotFoundExceptions.get(key);
173                if (e == null) {
174                    return null;
175                } else {
176                    throw new WrappedRuntimeException(e);
177                }
178            }
179
180            Class<?> suppliedClass = classMap.computeIfAbsent(key, new Function<String, Class<?>>() {
181                @Override
182                public Class<?> apply(String classKey) {
183                    try {
184                        return mappingFunction.get();
185                    } catch (ClassNotFoundException e) {
186                        classesNotFoundExceptions.put(key, e);
187                        throw new WrappedRuntimeException(e);
188                    } catch (NoFactoryAvailableException e) {
189                        classesNotFoundExceptions.put(key, e);
190                        throw new WrappedRuntimeException(e);
191                    } catch (IOException e) {
192                        throw new WrappedRuntimeException(e);
193                    }
194                }
195            });
196
197            if (suppliedClass == null) {
198                // mark the key as non-resolvable to prevent pointless searching
199                classesNotFound.put(key, Boolean.TRUE);
200            }
201
202            return suppliedClass;
203        } catch (WrappedRuntimeException e) {
204            if (e.getCause() instanceof ClassNotFoundException) {
205                throw (ClassNotFoundException)e.getCause();
206            } else if (e.getCause() instanceof NoFactoryAvailableException) {
207                throw (NoFactoryAvailableException)e.getCause();
208            } else if (e.getCause() instanceof IOException) {
209                throw (IOException)e.getCause();
210            } else {
211                throw new RuntimeException(e.getCause());
212            }
213        }
214    }
215
216    @FunctionalInterface
217    protected interface ClassSupplier {
218        Class<?> get() throws ClassNotFoundException, IOException;
219    }
220
221    private final class WrappedRuntimeException extends RuntimeException {
222        WrappedRuntimeException(Exception e) {
223            super(e);
224        }
225    }
226}