| /* |
| * 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.commons.jocl; |
| |
| import java.lang.reflect.Constructor; |
| import java.lang.reflect.InvocationTargetException; |
| |
| /** |
| * Miscellaneous {@link Constructor} related utility functions. |
| * |
| * @author Rodney Waldhoff |
| * @version $Revision$ $Date$ |
| */ |
| public class ConstructorUtil { |
| /** |
| * Returns a {@link Constructor} for the given method signature, or <tt>null</tt> |
| * if no such <tt>Constructor</tt> can be found. |
| * |
| * @param type the (non-<tt>null</tt>) type of {@link Object} the returned {@link Constructor} should create |
| * @param argTypes a non-<tt>null</tt> array of types describing the parameters to the {@link Constructor}. |
| * @return a {@link Constructor} for the given method signature, or <tt>null</tt> |
| * if no such <tt>Constructor</tt> can be found. |
| * @see #invokeConstructor |
| */ |
| public static Constructor getConstructor(Class type, Class[] argTypes) { |
| if(null == type || null == argTypes) { |
| throw new NullPointerException(); |
| } |
| Constructor ctor = null; |
| try { |
| ctor = type.getConstructor(argTypes); |
| } catch(Exception e) { |
| ctor = null; |
| } |
| if(null == ctor) { |
| // no directly declared matching constructor, |
| // look for something that will work |
| // XXX this should really be more careful to |
| // adhere to the jls mechanism for late binding |
| Constructor[] ctors = type.getConstructors(); |
| for(int i=0;i<ctors.length;i++) { |
| Class[] paramtypes = ctors[i].getParameterTypes(); |
| if(paramtypes.length == argTypes.length) { |
| boolean canuse = true; |
| for(int j=0;j<paramtypes.length;j++) { |
| if(paramtypes[j].isAssignableFrom(argTypes[j])) { |
| continue; |
| } else { |
| canuse = false; |
| break; |
| } |
| } |
| if(canuse == true) { |
| ctor = ctors[i]; |
| break; |
| } |
| } |
| } |
| } |
| return ctor; |
| } |
| |
| /** |
| * Creates a new instance of the specified <tt><i>type</i></tt> |
| * using a {@link Constructor} described by the given parameter types |
| * and values. |
| * |
| * @param type the type of {@link Object} to be created |
| * @param argTypes a non-<tt>null</tt> array of types describing the parameters to the {@link Constructor}. |
| * @param argValues a non-<tt>null</tt> array containing the values of the parameters to the {@link Constructor}. |
| * @return a new instance of the specified <tt><i>type</i></tt> |
| * using a {@link Constructor} described by the given parameter types |
| * and values. |
| * @exception InstantiationException |
| * @exception IllegalAccessException |
| * @exception InvocationTargetException |
| */ |
| public static Object invokeConstructor(Class type, Class[] argTypes, Object[] argValues) throws InstantiationException, IllegalAccessException, InvocationTargetException { |
| return ConstructorUtil.getConstructor(type,argTypes).newInstance(argValues); |
| } |
| } |
| |
| |