#region License
/*
* Copyright 2002-2005 the original author or authors.
*
* Licensed 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.
*/
#endregion
using System;
using System.Collections;
using System.Reflection;
using System.Runtime.Serialization;
using Spring.Core.TypeResolution;
using Spring.Util;
using Spring.Reflection.Dynamic;
namespace Spring.Expressions{
/// <summary>
/// Represents parsed method node in the navigation expression.
/// </summary>
/// <author>Aleksandar Seovic</author>
[Serializable]
public class ConstructorNode : NodeWithArguments
{
private SafeConstructor constructor;
private IDictionary namedArgs;
private bool isParamArray = false;
private Type paramArrayType;
private int argumentCount;
/// <summary>
/// Create a new instance
/// </summary>
public ConstructorNode()
{
}
/// <summary>
/// Create a new instance
/// </summary>
public ConstructorNode(Type type)
:base(type.FullName)
{
}
/// <summary>
/// Create a new instance from SerializationInfo
/// </summary>
protected ConstructorNode(SerializationInfo info, StreamingContext context)
: base(info, context)
{
}
/// <summary>
/// Creates new instance of the type defined by this node.
/// </summary>
/// <param name="context">Context to evaluate expressions against.</param>
/// <param name="evalContext">Current expression evaluation context.</param>
/// <returns>Node's value.</returns>
protected override object Get(object context, EvaluationContext evalContext)
{
object[] argValues = ResolveArguments(evalContext);
IDictionary namedArgValues = ResolveNamedArguments(evalContext);
if (constructor == null)
{
lock(this)
{
if (constructor == null)
{
constructor = InitializeNode(argValues, namedArgValues);
}
}
}
object[] paramValues = (isParamArray ? ReflectionUtils.PackageParamArray(argValues, argumentCount, paramArrayType) : argValues);
object instance = constructor.Invoke(paramValues);
if (namedArgValues != null)
{
SetNamedArguments(instance, namedArgValues);
}
return instance;
}
/// <summary>
/// Determines the type of object that should be instantiated.
/// </summary>
/// <param name="typeName">
/// The type name to resolve.
/// </param>
/// <returns>
/// The type of object that should be instantiated.
/// </returns>
/// <exception cref="TypeLoadException">
/// If the type cannot be resolved.
/// </exception>
protected virtual Type GetObjectType(string typeName)
{
return TypeResolutionUtils.ResolveType(typeName);
}
/// <summary>
/// Initializes this node by caching necessary constructor and property info.
/// </summary>
/// <param name="argValues"></param>
/// <param name="namedArgValues"></param>
private SafeConstructor InitializeNode(object[] argValues, IDictionary namedArgValues)
{
SafeConstructor ctor = null;
Type objectType = GetObjectType(this.getText().Trim());
// cache constructor info
ConstructorInfo ci = GetBestConstructor(objectType, argValues);
if (ci == null)
{
throw new ArgumentException(
String.Format("Constructor for the type [{0}] with a specified " +
"number and types of arguments does not exist.",
objectType.FullName));
}
else
{
ParameterInfo[] parameters = ci.GetParameters();
if (parameters.Length > 0)
{
ParameterInfo lastParameter = parameters[parameters.Length - 1];
isParamArray = lastParameter.GetCustomAttributes(typeof(ParamArrayAttribute), false).Length > 0;
if (isParamArray)
{
paramArrayType = lastParameter.ParameterType.GetElementType();
argumentCount = parameters.Length;
}
}
ctor = new SafeConstructor(ci);
}
// cache named args info
if (namedArgValues != null)
{
namedArgs = new Hashtable(namedArgValues.Count);
foreach (string name in namedArgValues.Keys)
{
this.namedArgs[name] = Expression.ParseProperty(name);
}
}
return ctor;
}
/// <summary>
/// Sets the named arguments (properties).
/// </summary>
/// <param name="instance">Instance to set property values on.</param>
/// <param name="namedArgValues">Argument (property) name to value mappings.</param>
private void SetNamedArguments(object instance, IDictionary namedArgValues)
{
foreach (string name in namedArgValues.Keys)
{
IExpression property = (IExpression) namedArgs[name];
property.SetValue(instance, namedArgValues[name]);
}
}
private static ConstructorInfo GetBestConstructor(Type type, object[] argValues)
{
ConstructorInfo[] candidates = GetCandidateConstructors(type, argValues.Length);
if (candidates.Length > 0)
{
return ReflectionUtils.GetConstructorByArgumentValues(candidates, argValues);
}
return null;
}
private static ConstructorInfo[] GetCandidateConstructors(Type type, int argCount)
{
ConstructorInfo[] ctors = type.GetConstructors(BindingFlags.Instance|BindingFlags.Public|BindingFlags.NonPublic);
ArrayList matches = new ArrayList();
foreach (ConstructorInfo ctor in ctors)
{
ParameterInfo[] parameters = ctor.GetParameters();
if (parameters.Length == argCount)
{
matches.Add(ctor);
}
else if (parameters.Length > 0)
{
ParameterInfo lastParameter = parameters[parameters.Length - 1];
if (lastParameter.GetCustomAttributes(typeof(ParamArrayAttribute), false).Length > 0)
{
matches.Add(ctor);
}
}
}
return (ConstructorInfo[]) matches.ToArray(typeof(ConstructorInfo));
}
}
}
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