001/* 002 * Copyright 2002-2017 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.lang.Nullable; 026import org.springframework.util.ReflectionUtils; 027 028/** 029 * A simple ConstructorExecutor implementation that runs a constructor using reflective 030 * invocation. 031 * 032 * @author Andy Clement 033 * @author Juergen Hoeller 034 * @since 3.0 035 */ 036public class ReflectiveConstructorExecutor implements ConstructorExecutor { 037 038 private final Constructor<?> ctor; 039 040 @Nullable 041 private final Integer varargsPosition; 042 043 044 public ReflectiveConstructorExecutor(Constructor<?> ctor) { 045 this.ctor = ctor; 046 if (ctor.isVarArgs()) { 047 this.varargsPosition = ctor.getParameterCount() - 1; 048 } 049 else { 050 this.varargsPosition = null; 051 } 052 } 053 054 @Override 055 public TypedValue execute(EvaluationContext context, Object... arguments) throws AccessException { 056 try { 057 ReflectionHelper.convertArguments( 058 context.getTypeConverter(), arguments, this.ctor, this.varargsPosition); 059 if (this.ctor.isVarArgs()) { 060 arguments = ReflectionHelper.setupArgumentsForVarargsInvocation( 061 this.ctor.getParameterTypes(), arguments); 062 } 063 ReflectionUtils.makeAccessible(this.ctor); 064 return new TypedValue(this.ctor.newInstance(arguments)); 065 } 066 catch (Exception ex) { 067 throw new AccessException("Problem invoking constructor: " + this.ctor, ex); 068 } 069 } 070 071 public Constructor<?> getConstructor() { 072 return this.ctor; 073 } 074 075}