/*
* Copyright 2004-2010 the Seasar Foundation and the Others.
*
* Licensed 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.slim3.controller;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import org.slim3.util.WrapRuntimeException;
/**
* The {@link ClassLoader} for hot reloading.
*
* @author higa
* @since 1.0.0
*/
public class HotReloadingClassLoader extends ClassLoader {
/**
* The root package name.
*/
protected String rootPackageName;
/**
* The cool package name.
*/
protected String coolPackageName;
/**
* Constructor
*
* @param parentClassLoader
* the parent class loader.
* @param rootPackageName
* the root package name
* @param coolPackageName
* the cool package name
* @throws NullPointerException
* if the rootPackageName parameter is null or if the
* coolPackageName parameter is null
*/
public HotReloadingClassLoader(ClassLoader parentClassLoader,
String rootPackageName, String coolPackageName)
throws NullPointerException {
super(parentClassLoader);
if (rootPackageName == null) {
throw new NullPointerException(
"The rootPackageName parameter is null.");
}
if (coolPackageName == null) {
throw new NullPointerException(
"The coolPackageName parameter is null.");
}
this.rootPackageName = rootPackageName;
this.coolPackageName = coolPackageName;
}
/**
* Constructor for customization.
*
* @param parentClassLoader
* the parent class loader.
*/
protected HotReloadingClassLoader(ClassLoader parentClassLoader) {
super(parentClassLoader);
}
@Override
public Class<?> loadClass(String className, boolean resolve)
throws ClassNotFoundException {
if (isTarget(className)) {
Class<?> clazz = findLoadedClass(className);
if (clazz != null) {
return clazz;
}
int index = className.lastIndexOf('.');
if (index >= 0) {
String packageName = className.substring(0, index);
if (getPackage(packageName) == null) {
try {
definePackage(
packageName,
null,
null,
null,
null,
null,
null,
null);
} catch (IllegalArgumentException ignore) {
}
}
}
clazz = defineClass(className, resolve);
if (clazz != null) {
return clazz;
}
}
return super.loadClass(className, resolve);
}
/**
* Defines the class.
*
* @param className
* the class name
* @param resolve
* whether the class is resolved
* @return the class
*/
protected Class<?> defineClass(String className, boolean resolve) {
Class<?> clazz;
String path = className.replace('.', '/') + ".class";
InputStream is = getInputStream(path);
if (is != null) {
clazz = defineClass(className, is);
if (resolve) {
resolveClass(clazz);
}
return clazz;
}
return null;
}
/**
* Defines the class.
*
* @param className
* the class name
* @param is
* the input stream
* @return the class
*/
protected Class<?> defineClass(String className, InputStream is) {
return defineClass(className, getBytes(is));
}
/**
* Defines the class.
*
* @param className
* the class name
* @param bytes
* the array of bytes.
* @return the class
*/
protected Class<?> defineClass(String className, byte[] bytes) {
return defineClass(className, bytes, 0, bytes.length);
}
/**
* Returns the input stream.
*
* @param path
* the path
* @return the input stream
*/
protected InputStream getInputStream(String path) {
try {
URL url = getResource(path);
if (url == null) {
return null;
}
URLConnection connection = url.openConnection();
connection.setUseCaches(false);
return connection.getInputStream();
} catch (IOException ignore) {
return null;
}
}
/**
* Returns input stream data as the array of bytes.
*
* @param is
* the input stream
* @return the array of bytes
* @throws RuntimeException
* if {@link IOException} is encountered
*/
protected byte[] getBytes(InputStream is) throws RuntimeException {
byte[] bytes = null;
byte[] buf = new byte[8192];
try {
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int n = 0;
while ((n = is.read(buf, 0, buf.length)) != -1) {
baos.write(buf, 0, n);
}
bytes = baos.toByteArray();
} finally {
if (is != null) {
is.close();
}
}
} catch (IOException e) {
throw new WrapRuntimeException(e);
}
return bytes;
}
/**
* Determines if the class is the target of hot deployment.
*
* @param className
* the class name
* @return whether the class is the target of hot deployment
*/
protected boolean isTarget(String className) {
if (!className.startsWith(rootPackageName + ".")) {
return false;
}
if (className.startsWith(rootPackageName + "." + coolPackageName + ".")) {
return false;
}
return true;
}
}
|