| package org.apache.velocity.util.introspection; |
| |
| /* |
| * 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. |
| */ |
| |
| import org.slf4j.Logger; |
| |
| import java.lang.reflect.Method; |
| |
| /** |
| * This basic function of this class is to return a Method |
| * object for a particular class given the name of a method |
| * and the parameters to the method in the form of an Object[] |
| * |
| * The first time the Introspector sees a |
| * class it creates a class method map for the |
| * class in question. Basically the class method map |
| * is a Hastable where Method objects are keyed by a |
| * concatenation of the method name and the names of |
| * classes that make up the parameters. |
| * |
| * For example, a method with the following signature: |
| * |
| * public void method(String a, StringBuffer b) |
| * |
| * would be mapped by the key: |
| * |
| * "method" + "java.lang.String" + "java.lang.StringBuffer" |
| * |
| * This mapping is performed for all the methods in a class |
| * and stored for |
| * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a> |
| * @author <a href="mailto:bob@werken.com">Bob McWhirter</a> |
| * @author <a href="mailto:szegedia@freemail.hu">Attila Szegedi</a> |
| * @author <a href="mailto:paulo.gaspar@krankikom.de">Paulo Gaspar</a> |
| * @author <a href="mailto:henning@apache.org">Henning P. Schmiedehausen</a> |
| * @version $Id$ |
| */ |
| public class Introspector extends IntrospectorBase |
| { |
| /** |
| * @param log A Logger object to use for the introspector. |
| * @since 1.5 |
| */ |
| public Introspector(final Logger log) |
| { |
| super(log); |
| } |
| |
| /** |
| * Gets the method defined by <code>name</code> and |
| * <code>params</code> for the Class <code>c</code>. |
| * |
| * @param c Class in which the method search is taking place |
| * @param name Name of the method being searched for |
| * @param params An array of Objects (not Classes) that describe the |
| * the parameters |
| * |
| * @return The desired Method object. |
| * @throws IllegalArgumentException When the parameters passed in can not be used for introspection. |
| */ |
| public Method getMethod(final Class c, final String name, final Object[] params) |
| throws IllegalArgumentException |
| { |
| try |
| { |
| return super.getMethod(c, name, params); |
| } |
| catch(MethodMap.AmbiguousException ae) |
| { |
| /* |
| * whoops. Ambiguous. Make a nice log message and return null... |
| */ |
| |
| StringBuffer msg = new StringBuffer("Introspection Error : Ambiguous method invocation ") |
| .append(name) |
| .append("("); |
| |
| for (int i = 0; i < params.length; i++) |
| { |
| if (i > 0) |
| { |
| msg.append(", "); |
| } |
| |
| if (params[i] == null) |
| { |
| msg.append("null"); |
| } |
| else |
| { |
| msg.append(params[i].getClass().getName()); |
| } |
| } |
| |
| msg.append(") for class ") |
| .append(c); |
| |
| log.debug(msg.toString()); |
| } |
| |
| return null; |
| } |
| |
| } |