NOTE: if you specify a protected or private method this method will call {@link + * Method#setAccessible} to make the method accessible. If you're writing secure code or need + * to run in a sandbox, don't use this functionality. + * + * @throws IllegalArgumentException if the supplied method name does not correspond to a + * non-static zero-argument method of the supplied instance's class. + */ + public static Runnable asRunnable (Object instance, String methodName) + { + Class clazz = instance.getClass(); + Method method = findMethod(clazz, methodName); + if (Modifier.isStatic(method.getModifiers())) { + throw new IllegalArgumentException( + clazz.getName() + "." + methodName + "() must not be static"); + } + return new MethodRunner(method, instance); + } + + /** + * Creates a runnable that invokes the specified static method via reflection. + * + *
NOTE: if you specify a protected or private method this method will call {@link + * Method#setAccessible} to make the method accessible. If you're writing secure code or need + * to run in a sandbox, don't use this functionality. + * + * @throws IllegalArgumentException if the supplied method name does not correspond to a static + * zero-argument method of the supplied class. + */ + public static Runnable asRunnable (Class clazz, String methodName) + { + Method method = findMethod(clazz, methodName); + if (!Modifier.isStatic(method.getModifiers())) { + throw new IllegalArgumentException( + clazz.getName() + "." + methodName + "() must be static"); + } + return new MethodRunner(method, null); + } + + protected static Method findMethod (Class clazz, String methodName) + { + for (Method method : clazz.getDeclaredMethods()) { + if (method.getName().equals(methodName) && method.getParameterTypes().length == 0) { + if (!method.isAccessible()) { + method.setAccessible(true); + } + return method; + } + } + throw new IllegalArgumentException(clazz.getName() + "." + methodName + "() not found"); + } + + protected static class MethodRunner implements Runnable + { + public MethodRunner (Method method, Object instance) { + _method = method; + _instance = instance; + } + + public void run () { + try { + _method.invoke(_instance); + } catch (IllegalAccessException iae) { + log.warning("Failed to invoke " + _method.getName() + ": " + iae); + } catch (InvocationTargetException ite) { + log.warning("Invocation of " + _method.getName() + " failed", ite); + } + } + + protected Method _method; + protected Object _instance; + } + + protected Runnables () + { + // no constructy + } +} diff --git a/src/java/com/samskivert/util/tests/RunnablesTest.java b/src/java/com/samskivert/util/tests/RunnablesTest.java new file mode 100644 index 00000000..ebd9439a --- /dev/null +++ b/src/java/com/samskivert/util/tests/RunnablesTest.java @@ -0,0 +1,62 @@ +// +// $Id$ +// +// samskivert library - useful routines for java programs +// Copyright (C) 2001-2008 Michael Bayne +// +// This library is free software; you can redistribute it and/or modify it +// under the terms of the GNU Lesser General Public License as published +// by the Free Software Foundation; either version 2.1 of the License, or +// (at your option) any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// Lesser General Public License for more details. +// +// You should have received a copy of the GNU Lesser General Public +// License along with this library; if not, write to the Free Software +// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + +package com.samskivert.util.tests; + +import org.junit.*; +import static org.junit.Assert.*; + +import com.samskivert.util.Runnables; + +/** + * Does something extraordinary. + */ +public class RunnablesTest +{ + @Test(expected=IllegalArgumentException.class) public void testWrapStaticFail () + { + Runnables.asRunnable(this, "staticMethod"); + } + + @Test(expected=IllegalArgumentException.class) public void testWrapNonStaticFail () + { + Runnables.asRunnable(RunnablesTest.class, "instanceMethod"); + } + + @Test public void testWrapInstance () + { + Runnables.asRunnable(this, "instanceMethod"); + } + + @Test public void testWrapStatic () + { + Runnables.asRunnable(RunnablesTest.class, "staticMethod"); + } + + protected void instanceMethod () + { + // noop! + } + + protected static void staticMethod () + { + // noop! + } +}