001/*
002 * Copyright 2002-2014 the original author or authors.
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 *      https://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
017package org.springframework.expression.spel.support;
018
019import java.lang.reflect.Constructor;
020
021import org.springframework.expression.AccessException;
022import org.springframework.expression.ConstructorExecutor;
023import org.springframework.expression.EvaluationContext;
024import org.springframework.expression.TypedValue;
025import org.springframework.util.ReflectionUtils;
026
027/**
028 * A simple ConstructorExecutor implementation that runs a constructor using reflective
029 * invocation.
030 *
031 * @author Andy Clement
032 * @author Juergen Hoeller
033 * @since 3.0
034 */
035public class ReflectiveConstructorExecutor implements ConstructorExecutor {
036
037        private final Constructor<?> ctor;
038
039        private final Integer varargsPosition;
040
041
042        public ReflectiveConstructorExecutor(Constructor<?> ctor) {
043                this.ctor = ctor;
044                if (ctor.isVarArgs()) {
045                        Class<?>[] paramTypes = ctor.getParameterTypes();
046                        this.varargsPosition = paramTypes.length - 1;
047                }
048                else {
049                        this.varargsPosition = null;
050                }
051        }
052
053        @Override
054        public TypedValue execute(EvaluationContext context, Object... arguments) throws AccessException {
055                try {
056                        if (arguments != null) {
057                                ReflectionHelper.convertArguments(context.getTypeConverter(), arguments, this.ctor, this.varargsPosition);
058                        }
059                        if (this.ctor.isVarArgs()) {
060                                arguments = ReflectionHelper.setupArgumentsForVarargsInvocation(this.ctor.getParameterTypes(), arguments);
061                        }
062                        ReflectionUtils.makeAccessible(this.ctor);
063                        return new TypedValue(this.ctor.newInstance(arguments));
064                }
065                catch (Exception ex) {
066                        throw new AccessException("Problem invoking constructor: " + this.ctor, ex);
067                }
068        }
069
070        public Constructor<?> getConstructor() {
071                return this.ctor;
072        }
073
074}