001/*
002 * (C) Copyright 2006-2011 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     bstefanescu
018 *
019 * $Id$
020 */
021
022package org.nuxeo.ecm.platform.rendering.fm.extensions;
023
024import java.lang.reflect.Constructor;
025import java.util.List;
026
027import freemarker.template.TemplateMethodModelEx;
028import freemarker.template.TemplateModelException;
029
030/**
031 * @author <a href="mailto:[email protected]">Bogdan Stefanescu</a>
032 */
033public class NewMethod implements TemplateMethodModelEx {
034
035    public Object exec(List arguments) throws TemplateModelException {
036        int size = arguments.size();
037        if (size < 1) {
038            throw new TemplateModelException("Invalid number of arguments for new(class, ...) method");
039        }
040
041        Class<?> klass;
042        try {
043            String className = (String) arguments.get(0);
044            klass = Class.forName(className);
045            if (size == 1) {
046                return klass.newInstance();
047            }
048        } catch (ReflectiveOperationException e) {
049            throw new TemplateModelException("Failed to isntantiate the object", e);
050        }
051        arguments.remove(0);
052        Object[] ar = arguments.toArray();
053        size--;
054        Constructor<?>[] ctors = klass.getConstructors();
055        for (Constructor<?> ctor : ctors) {
056            Class<?>[] params = ctor.getParameterTypes(); // this is cloning params
057            if (params.length == size) { // try this one
058                try {
059                    return ctor.newInstance(ar);
060                } catch (ReflectiveOperationException e) {
061                    // continue
062                }
063            }
064        }
065        throw new TemplateModelException("No suitable constructor found");
066    }
067
068}