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;
028import org.apache.camel.util.StringHelper;
029
030/**
031 * Default class resolver that uses regular class loader to load classes.
032 */
033public class DefaultClassResolver implements ClassResolver, CamelContextAware {
034
035    private CamelContext camelContext;
036
037    public DefaultClassResolver() {
038    }
039
040    public DefaultClassResolver(CamelContext camelContext) {
041        this.camelContext = camelContext;
042    }
043
044    public void setCamelContext(CamelContext camelContext) {
045        this.camelContext = camelContext;
046    }
047
048    public CamelContext getCamelContext() {
049        return camelContext;
050    }
051
052    public Class<?> resolveClass(String name) {
053        Class<?> answer = loadClass(name, DefaultClassResolver.class.getClassLoader());
054        if (answer == null && getApplicationContextClassLoader() != null) {
055            // fallback and use application context class loader
056            answer = loadClass(name, getApplicationContextClassLoader());
057        }
058        return answer;
059    }
060
061    public <T> Class<T> resolveClass(String name, Class<T> type) {
062        Class<T> answer = CastUtils.cast(loadClass(name, DefaultClassResolver.class.getClassLoader()));
063        if (answer == null && getApplicationContextClassLoader() != null) {
064            // fallback and use application context class loader
065            answer = CastUtils.cast(loadClass(name, getApplicationContextClassLoader()));
066        }
067        return answer;
068    }
069
070    public Class<?> resolveClass(String name, ClassLoader loader) {
071        return loadClass(name, loader);
072    }
073
074    public <T> Class<T> resolveClass(String name, Class<T> type, ClassLoader loader) {
075        return CastUtils.cast(loadClass(name, loader));
076    }
077
078    public Class<?> resolveMandatoryClass(String name) throws ClassNotFoundException {
079        Class<?> answer = resolveClass(name);
080        if (answer == null) {
081            throw new ClassNotFoundException(name);
082        }
083        return answer;
084    }
085
086    public <T> Class<T> resolveMandatoryClass(String name, Class<T> type) throws ClassNotFoundException {
087        Class<T> answer = resolveClass(name, type);
088        if (answer == null) {
089            throw new ClassNotFoundException(name);
090        }
091        return answer;
092    }
093
094    public Class<?> resolveMandatoryClass(String name, ClassLoader loader) throws ClassNotFoundException {
095        Class<?> answer = resolveClass(name, loader);
096        if (answer == null) {
097            throw new ClassNotFoundException(name);
098        }
099        return answer;
100    }
101
102    public <T> Class<T> resolveMandatoryClass(String name, Class<T> type, ClassLoader loader) throws ClassNotFoundException {
103        Class<T> answer = resolveClass(name, type, loader);
104        if (answer == null) {
105            throw new ClassNotFoundException(name);
106        }
107        return answer;
108    }
109
110    public InputStream loadResourceAsStream(String uri) {
111        StringHelper.notEmpty(uri, "uri");
112        return ObjectHelper.loadResourceAsStream(uri, getApplicationContextClassLoader());
113    }
114
115    public URL loadResourceAsURL(String uri) {
116        StringHelper.notEmpty(uri, "uri");
117        return ObjectHelper.loadResourceAsURL(uri, getApplicationContextClassLoader());
118    }
119
120    public Enumeration<URL> loadResourcesAsURL(String uri) {
121        return loadAllResourcesAsURL(uri);
122    }
123
124    public Enumeration<URL> loadAllResourcesAsURL(String uri) {
125        StringHelper.notEmpty(uri, "uri");
126        return ObjectHelper.loadResourcesAsURL(uri);
127    }
128
129    protected Class<?> loadClass(String name, ClassLoader loader) {
130        StringHelper.notEmpty(name, "name");
131        return ObjectHelper.loadClass(name, loader);
132    }
133
134    protected ClassLoader getApplicationContextClassLoader() {
135        return camelContext != null ? camelContext.getApplicationContextClassLoader() : null;
136    }
137
138}