| /* |
| * 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.tools.ant.util; |
| |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| import org.apache.tools.ant.BuildException; |
| import java.lang.reflect.Field; |
| |
| /** |
| * Utility class to handle reflection on java objects. |
| * The class contains static methods to call reflection |
| * methods, catch any exceptions, converting them |
| * to BuildExceptions. |
| */ |
| // CheckStyle:FinalClassCheck OFF - backward compatible |
| public class ReflectUtil { |
| |
| /** private constructor */ |
| private ReflectUtil() { |
| } |
| |
| /** |
| * Call a method on the object with no parameters. |
| * @param obj the object to invoke the method on. |
| * @param methodName the name of the method to call |
| * @return the object returned by the method |
| */ |
| public static Object invoke(Object obj, String methodName) { |
| try { |
| Method method; |
| method = obj.getClass().getMethod( |
| methodName, (Class[]) null); |
| return method.invoke(obj, (Object[]) null); |
| } catch (Exception t) { |
| throwBuildException(t); |
| return null; // NotReached |
| } |
| } |
| |
| /** |
| * Call a method on the object with no parameters. |
| * Note: Unlike the invoke method above, this |
| * calls class or static methods, not instance methods. |
| * @param obj the object to invoke the method on. |
| * @param methodName the name of the method to call |
| * @return the object returned by the method |
| */ |
| public static Object invokeStatic(Object obj, String methodName) { |
| try { |
| Method method; |
| method = ((Class) obj).getMethod( |
| methodName, (Class[]) null); |
| return method.invoke(obj, (Object[]) null); |
| } catch (Exception t) { |
| throwBuildException(t); |
| return null; // NotReached |
| } |
| } |
| |
| /** |
| * Call a method on the object with one argument. |
| * @param obj the object to invoke the method on. |
| * @param methodName the name of the method to call |
| * @param argType the type of argument. |
| * @param arg the value of the argument. |
| * @return the object returned by the method |
| */ |
| public static Object invoke( |
| Object obj, String methodName, Class argType, Object arg) { |
| try { |
| Method method; |
| method = obj.getClass().getMethod( |
| methodName, new Class[] {argType}); |
| return method.invoke(obj, new Object[] {arg}); |
| } catch (Exception t) { |
| throwBuildException(t); |
| return null; // NotReached |
| } |
| } |
| |
| /** |
| * Call a method on the object with two argument. |
| * @param obj the object to invoke the method on. |
| * @param methodName the name of the method to call |
| * @param argType1 the type of the first argument. |
| * @param arg1 the value of the first argument. |
| * @param argType2 the type of the second argument. |
| * @param arg2 the value of the second argument. |
| * @return the object returned by the method |
| */ |
| public static Object invoke( |
| Object obj, String methodName, Class argType1, Object arg1, |
| Class argType2, Object arg2) { |
| try { |
| Method method; |
| method = obj.getClass().getMethod( |
| methodName, new Class[] {argType1, argType2}); |
| return method.invoke(obj, new Object[] {arg1, arg2}); |
| } catch (Exception t) { |
| throwBuildException(t); |
| return null; // NotReached |
| } |
| } |
| |
| /** |
| * Get the value of a field in an object. |
| * @param obj the object to look at. |
| * @param fieldName the name of the field in the object. |
| * @return the value of the field. |
| * @throws BuildException if there is an error. |
| */ |
| public static Object getField(Object obj, String fieldName) |
| throws BuildException { |
| try { |
| Field field = obj.getClass().getDeclaredField(fieldName); |
| field.setAccessible(true); |
| return field.get(obj); |
| } catch (Exception t) { |
| throwBuildException(t); |
| return null; // NotReached |
| } |
| } |
| |
| /** |
| * A method to convert an invocationTargetException to |
| * a buildexception and throw it. |
| * @param t the invocation target exception. |
| * @throws BuildException the converted exception. |
| */ |
| public static void throwBuildException(Exception t) |
| throws BuildException { |
| throw toBuildException(t); |
| } |
| |
| /** |
| * A method to convert an invocationTargetException to |
| * a buildexception. |
| * @param t the invocation target exception. |
| * @return the converted exception. |
| * @since ant 1.7.1 |
| */ |
| public static BuildException toBuildException(Exception t) { |
| if (t instanceof InvocationTargetException) { |
| Throwable t2 = ((InvocationTargetException) t) |
| .getTargetException(); |
| if (t2 instanceof BuildException) { |
| return (BuildException) t2; |
| } |
| return new BuildException(t2); |
| } else { |
| return new BuildException(t); |
| } |
| } |
| |
| /** |
| * A method to test if an object responds to a given |
| * message (method call) |
| * @param o the object |
| * @param methodName the method to check for |
| * @return true if the object has the method. |
| * @throws BuildException if there is a problem. |
| */ |
| public static boolean respondsTo(Object o, String methodName) |
| throws BuildException { |
| try { |
| Method[] methods = o.getClass().getMethods(); |
| for (int i = 0; i < methods.length; i++) { |
| if (methods[i].getName().equals(methodName)) { |
| return true; |
| } |
| } |
| return false; |
| } catch (Exception t) { |
| throw toBuildException(t); |
| } |
| } |
| } |