| /* |
| * 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.bcel.util; |
| |
| import java.lang.reflect.Method; |
| import java.lang.reflect.Modifier; |
| |
| /** |
| * Java interpreter replacement, i.e., wrapper that uses its own ClassLoader |
| * to modify/generate classes as they're requested. You can take this as a template |
| * for your own applications. |
| * <p> |
| * Call this wrapper with: |
| * </p> |
| * <pre>java org.apache.bcel.util.JavaWrapper <real.class.name> [arguments]</pre> |
| * <p> |
| * To use your own class loader you can set the "bcel.classloader" system property. |
| * </p> |
| * <pre>java org.apache.bcel.util.JavaWrapper -Dbcel.classloader=foo.MyLoader <real.class.name> [arguments]</pre> |
| * |
| * @see ClassLoader |
| */ |
| public class JavaWrapper { |
| |
| private final java.lang.ClassLoader loader; |
| |
| |
| private static java.lang.ClassLoader getClassLoader() { |
| final String s = System.getProperty("bcel.classloader"); |
| if ((s == null) || "".equals(s)) { |
| throw new IllegalArgumentException("The property 'bcel.classloader' must be defined"); |
| } |
| try { |
| return (java.lang.ClassLoader) Class.forName(s).newInstance(); |
| } catch (final Exception e) { |
| throw new RuntimeException(e.toString(), e); |
| } |
| } |
| |
| |
| public JavaWrapper(final java.lang.ClassLoader loader) { |
| this.loader = loader; |
| } |
| |
| |
| public JavaWrapper() { |
| this(getClassLoader()); |
| } |
| |
| |
| /** Runs the main method of the given class with the arguments passed in argv |
| * |
| * @param class_name the fully qualified class name |
| * @param argv the arguments just as you would pass them directly |
| */ |
| public void runMain( final String class_name, final String[] argv ) throws ClassNotFoundException { |
| final Class<?> cl = loader.loadClass(class_name); |
| Method method = null; |
| try { |
| method = cl.getMethod("main", argv.getClass()); |
| /* Method main is sane ? |
| */ |
| final int m = method.getModifiers(); |
| final Class<?> r = method.getReturnType(); |
| if (!(Modifier.isPublic(m) && Modifier.isStatic(m)) || Modifier.isAbstract(m) |
| || (r != Void.TYPE)) { |
| throw new NoSuchMethodException(); |
| } |
| } catch (final NoSuchMethodException no) { |
| System.out.println("In class " + class_name |
| + ": public static void main(String[] argv) is not defined"); |
| return; |
| } |
| try { |
| method.invoke(null, argv); |
| } catch (final Exception ex) { |
| ex.printStackTrace(); |
| } |
| } |
| |
| |
| /** Default main method used as wrapper, expects the fully qualified class name |
| * of the real class as the first argument. |
| */ |
| public static void main( final String[] argv ) throws Exception { |
| /* Expects class name as first argument, other arguments are by-passed. |
| */ |
| if (argv.length == 0) { |
| System.out.println("Missing class name."); |
| return; |
| } |
| final String class_name = argv[0]; |
| final String[] new_argv = new String[argv.length - 1]; |
| System.arraycopy(argv, 1, new_argv, 0, new_argv.length); |
| final JavaWrapper wrapper = new JavaWrapper(); |
| wrapper.runMain(class_name, new_argv); |
| } |
| } |