/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jasper.servlet;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLClassLoader;
/**
* Class loader for loading servlet class files (corresponding to JSP files) and tag handler class files (corresponding
* to tag files).
*/
public class JasperLoader extends URLClassLoader {
private final String packageName;
public JasperLoader(URL[] urls, ClassLoader parent, String packageName) {
super(urls, parent);
this.packageName = packageName;
}
/**
* Load the class with the specified name. This method searches for classes in the same manner as
* <code>loadClass(String, boolean)</code> with <code>false</code> as the second argument.
*
* @param name Name of the class to be loaded
*
* @exception ClassNotFoundException if the class was not found
*/
@Override
public Class<?> loadClass(String name) throws ClassNotFoundException {
return loadClass(name, false);
}
/**
* Load the class with the specified name, searching using the following algorithm until it finds and returns the
* class. If the class cannot be found, returns <code>ClassNotFoundException</code>.
* <ul>
* <li>Call <code>findLoadedClass(String)</code> to check if the class has already been loaded. If it has, the same
* <code>Class</code> object is returned.</li>
* <li>If the <code>delegate</code> property is set to <code>true</code>, call the <code>loadClass()</code> method
* of the parent class loader, if any.</li>
* <li>Call <code>findClass()</code> to find this class in our locally defined repositories.</li>
* <li>Call the <code>loadClass()</code> method of our parent class loader, if any.</li>
* </ul>
* If the class was found using the above steps, and the <code>resolve</code> flag is <code>true</code>, this method
* will then call <code>resolveClass(Class)</code> on the resulting Class object.
*
* @param name Name of the class to be loaded
* @param resolve If <code>true</code> then resolve the class
*
* @exception ClassNotFoundException if the class was not found
*/
@Override
public synchronized Class<?> loadClass(final String name, boolean resolve) throws ClassNotFoundException {
Class<?> clazz;
// (0) Check our previously loaded class cache
clazz = findLoadedClass(name);
if (clazz != null) {
if (resolve) {
resolveClass(clazz);
}
return clazz;
}
if (!name.startsWith(packageName + '.')) {
// Class is not in org.apache.jsp, therefore, have our
// parent load it
clazz = getParent().loadClass(name);
if (resolve) {
resolveClass(clazz);
}
return clazz;
}
return findClass(name);
}
/**
* Delegate to parent
*
* @see java.lang.ClassLoader#getResourceAsStream(String)
*/
@Override
public InputStream getResourceAsStream(String name) {
InputStream is = getParent().getResourceAsStream(name);
if (is == null) {
URL url = findResource(name);
if (url != null) {
try {
is = url.openStream();
} catch (IOException ignore) {
// Ignore
}
}
}
return is;
}
}