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.InputStream;
020import java.net.URL;
021import java.util.Enumeration;
022
023import org.apache.camel.CamelContext;
024import org.apache.camel.CamelContextAware;
025import org.apache.camel.spi.ClassResolver;
026import org.apache.camel.util.CastUtils;
027import org.apache.camel.util.ObjectHelper;
028
029/**
030 * Default class resolver that uses regular class loader to load classes.
031 */
032public class DefaultClassResolver implements ClassResolver, CamelContextAware {
033
034    private CamelContext camelContext;
035
036    public DefaultClassResolver() {
037    }
038
039    public DefaultClassResolver(CamelContext camelContext) {
040        this.camelContext = camelContext;
041    }
042
043    public void setCamelContext(CamelContext camelContext) {
044        this.camelContext = camelContext;
045    }
046
047    public CamelContext getCamelContext() {
048        return camelContext;
049    }
050
051    public Class<?> resolveClass(String name) {
052        Class<?> answer = loadClass(name, DefaultClassResolver.class.getClassLoader());
053        if (answer == null && getApplicationContextClassLoader() != null) {
054            // fallback and use application context class loader
055            answer = loadClass(name, getApplicationContextClassLoader());
056        }
057        return answer;
058    }
059
060    public <T> Class<T> resolveClass(String name, Class<T> type) {
061        Class<T> answer = CastUtils.cast(loadClass(name, DefaultClassResolver.class.getClassLoader()));
062        if (answer == null && getApplicationContextClassLoader() != null) {
063            // fallback and use application context class loader
064            answer = CastUtils.cast(loadClass(name, getApplicationContextClassLoader()));
065        }
066        return answer;
067    }
068
069    public Class<?> resolveClass(String name, ClassLoader loader) {
070        return loadClass(name, loader);
071    }
072
073    public <T> Class<T> resolveClass(String name, Class<T> type, ClassLoader loader) {
074        return CastUtils.cast(loadClass(name, loader));
075    }
076
077    public Class<?> resolveMandatoryClass(String name) throws ClassNotFoundException {
078        Class<?> answer = resolveClass(name);
079        if (answer == null) {
080            throw new ClassNotFoundException(name);
081        }
082        return answer;
083    }
084
085    public <T> Class<T> resolveMandatoryClass(String name, Class<T> type) throws ClassNotFoundException {
086        Class<T> answer = resolveClass(name, type);
087        if (answer == null) {
088            throw new ClassNotFoundException(name);
089        }
090        return answer;
091    }
092
093    public Class<?> resolveMandatoryClass(String name, ClassLoader loader) throws ClassNotFoundException {
094        Class<?> answer = resolveClass(name, loader);
095        if (answer == null) {
096            throw new ClassNotFoundException(name);
097        }
098        return answer;
099    }
100
101    public <T> Class<T> resolveMandatoryClass(String name, Class<T> type, ClassLoader loader) throws ClassNotFoundException {
102        Class<T> answer = resolveClass(name, type, loader);
103        if (answer == null) {
104            throw new ClassNotFoundException(name);
105        }
106        return answer;
107    }
108
109    public InputStream loadResourceAsStream(String uri) {
110        ObjectHelper.notEmpty(uri, "uri");
111        return ObjectHelper.loadResourceAsStream(uri, getApplicationContextClassLoader());
112    }
113
114    public URL loadResourceAsURL(String uri) {
115        ObjectHelper.notEmpty(uri, "uri");
116        return ObjectHelper.loadResourceAsURL(uri, getApplicationContextClassLoader());
117    }
118
119    public Enumeration<URL> loadResourcesAsURL(String uri) {
120        return loadAllResourcesAsURL(uri);
121    }
122
123    public Enumeration<URL> loadAllResourcesAsURL(String uri) {
124        ObjectHelper.notEmpty(uri, "uri");
125        return ObjectHelper.loadResourcesAsURL(uri);
126    }
127
128    protected Class<?> loadClass(String name, ClassLoader loader) {
129        ObjectHelper.notEmpty(name, "name");
130        return ObjectHelper.loadClass(name, loader);
131    }
132
133    protected ClassLoader getApplicationContextClassLoader() {
134        return camelContext != null ? camelContext.getApplicationContextClassLoader() : null;
135    }
136
137}