/**
*
* Copyright 2005 The Apache Software Foundation
*
* 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.apache.geronimo.kernel;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import org.apache.geronimo.kernel.basic.BasicKernelFactory;
/**
* @version $Rev: 355877 $ $Date: 2005-12-11 03:48:27 +0100 (Sun, 11 Dec 2005) $
*/
public abstract class KernelFactory {
public static final String KERNEL_FACTORY_KEY = KernelFactory.class.getName();
public static KernelFactory newInstance() {
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
if (classLoader == null) {
classLoader = KernelFactory.class.getClassLoader();
}
// System property
try {
String kernelFactoryName = System.getProperty(KERNEL_FACTORY_KEY);
if (kernelFactoryName != null) {
return createKernelFactory(kernelFactoryName, classLoader);
}
} catch (SecurityException se) {
}
// Jar Service Specification - http://java.sun.com/j2se/1.3/docs/guide/jar/jar.html
String serviceId = "META-INF/services/" + KERNEL_FACTORY_KEY;
InputStream inputStream = null;
try {
inputStream = classLoader.getResourceAsStream(serviceId);
if (inputStream != null) {
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"));
String kernelFactoryName = reader.readLine();
reader.close();
if (kernelFactoryName != null && kernelFactoryName.length() > 0) {
return createKernelFactory(kernelFactoryName, classLoader);
}
}
} catch (Exception ignored) {
} finally {
if (inputStream != null) {
try {
inputStream.close();
} catch (IOException ignored) {
}
inputStream = null;
}
}
// Default is the basic kernel
return new BasicKernelFactory();
}
private static KernelFactory createKernelFactory(String className, ClassLoader classLoader) {
try {
return (KernelFactory) classLoader.loadClass(className).newInstance();
} catch (ClassCastException e) {
throw new KernelFactoryError("Kernel factory class does not implement KernelFactory: " + className);
} catch (ClassNotFoundException e) {
throw new KernelFactoryError("Kernel factory class not found: " + className);
} catch (Exception e) {
throw new KernelFactoryError("Unable to instantiate kernel factory class: " + className, e);
}
}
public abstract Kernel createKernel(String kernelName);
}