/*
* Copyright 2012-2016 the original author or authors.
*
* 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.springframework.boot.cli.archive;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Enumeration;
import java.util.jar.Attributes;
import java.util.jar.Manifest;
import org.springframework.boot.cli.app.SpringApplicationLauncher;
/**
* A launcher for a CLI application that has been compiled and packaged as a jar file.
*
* @author Andy Wilkinson
* @author Phillip Webb
*/
public final class PackagedSpringApplicationLauncher {
/**
* The entry containing the source class.
*/
public static final String SOURCE_ENTRY = "Spring-Application-Source-Classes";
/**
* The entry containing the start class.
*/
public static final String START_CLASS_ENTRY = "Start-Class";
private PackagedSpringApplicationLauncher() {
}
private void run(String[] args) throws Exception {
URLClassLoader classLoader = (URLClassLoader) Thread.currentThread()
.getContextClassLoader();
new SpringApplicationLauncher(classLoader).launch(getSources(classLoader), args);
}
private Object[] getSources(URLClassLoader classLoader) throws Exception {
Enumeration<URL> urls = classLoader.getResources("META-INF/MANIFEST.MF");
while (urls.hasMoreElements()) {
URL url = urls.nextElement();
Manifest manifest = new Manifest(url.openStream());
if (isCliPackaged(manifest)) {
String sources = manifest.getMainAttributes().getValue(SOURCE_ENTRY);
return loadClasses(classLoader, sources.split(","));
}
}
throw new IllegalStateException(
"Cannot locate " + SOURCE_ENTRY + " in MANIFEST.MF");
}
private boolean isCliPackaged(Manifest manifest) {
Attributes attributes = manifest.getMainAttributes();
String startClass = attributes.getValue(START_CLASS_ENTRY);
return getClass().getName().equals(startClass);
}
private Class<?>[] loadClasses(ClassLoader classLoader, String[] names)
throws ClassNotFoundException {
Class<?>[] classes = new Class<?>[names.length];
for (int i = 0; i < names.length; i++) {
classes[i] = classLoader.loadClass(names[i]);
}
return classes;
}
public static void main(String[] args) throws Exception {
new PackagedSpringApplicationLauncher().run(args);
}
}