ReplacedMethodOverride.cs :  » Inversion-of-Control-Dependency-Injection » Spring.net » Spring » Objects » Factory » Support » C# / CSharp Open Source

#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

#region Imports

using System;
using System.Collections.Specialized;
using System.Reflection;
using System.Text;
using Spring.Util;

#endregion

namespace Spring.Objects.Factory.Support{
  /// <summary>
  /// Represents the replacement of a method on a managed object by the IoC
  /// container.
  /// </summary>
  /// <remarks>
  /// <p>
  /// Note that this mechanism is <i>not</i> intended as a generic means of
  /// inserting crosscutting code: use AOP for that.
  /// </p>
  /// </remarks>
  /// <author>Rod Johnson</author>
  /// <author>Rick Evans (.NET)</author>
    [Serializable]
    public sealed class ReplacedMethodOverride : MethodOverride
  {
    private readonly string methodReplacerObjectName;
    private StringCollection typeIdentifiers = new StringCollection();

    /// <summary>
    /// Creates a new instance of the
    /// <see cref="ReplacedMethodOverride"/> class.
    /// </summary>
    /// <param name="methodName">
    /// The name of the method that is to be overridden.
    /// </param>
    /// <param name="methodReplacerObjectName">
    /// The object name of the <see cref="Spring.Objects.Factory.Support.IMethodReplacer"/>
    /// instance in the surrounding IoC container. 
    /// </param>
    /// <exception cref="System.ArgumentNullException">
    /// If either of the supplied arguments is <see langword="null"/> or
    /// contains only whitespace character(s).
    /// </exception>
    public ReplacedMethodOverride(string methodName, string methodReplacerObjectName)
      : base(methodName)
    {
      AssertUtils.ArgumentHasText(methodReplacerObjectName, "methodReplacerObjectName");
      this.methodReplacerObjectName = methodReplacerObjectName;
    }

    /// <summary>
    /// Add a fragment of a <see cref="System.Type"/> instance's <see cref="System.Type.FullName"/>
    /// such as <c>'Exception</c> or <c>System.Excep</c> to identify an argument
    /// <see cref="System.Type"/> for a dependency injected method.
    /// </summary>
    /// <param name="identifier">
    /// A (sub) string of a <see cref="System.Type"/> instance's <see cref="System.Type.FullName"/>.
    /// </param>
    /// <exception cref="System.ArgumentNullException">
    /// If the supplied <paramref name="identifier"/> is <see langword="null"/> or
    /// contains only whitespace character(s).
    /// </exception>
    /// <seeaso cref="Spring.Objects.Factory.Support.MethodOverride.Matches(MethodInfo)"/> 
    public void AddTypeIdentifier(string identifier)
    {
      AssertUtils.ArgumentHasText(identifier, "identifier");
      this.typeIdentifiers.Add(identifier);
    }

    /// <summary>
    /// The object name of the <see cref="Spring.Objects.Factory.Support.IMethodReplacer"/>
    /// instance in the surrounding IoC container. 
    /// </summary>
    public string MethodReplacerObjectName
    {
      get { return methodReplacerObjectName; }
    }

    /// <summary>
    /// Does this <see cref="Spring.Objects.Factory.Support.MethodOverride"/>
    /// match the supplied <paramref name="method"/>?
    /// </summary>
    /// <param name="method">The method to be checked.</param>
    /// <returns>
    /// <see lang="true"/> if this override matches the supplied <paramref name="method"/>.
    /// </returns>
    /// <exception cref="System.ArgumentNullException">
    /// If the supplied <paramref name="method"/> is <see langword="null"/>.
    /// </exception>
    public override bool Matches(MethodInfo method)
    {
      AssertUtils.ArgumentNotNull(method, "method");
      if (MethodName != method.Name && !(method.Name.EndsWith(MethodName)))
      {
        // can't ever match...
        return false;
      }
      if (!IsOverloaded)
      {
        // no need to worry about overloading...
        return true;
      }
      // if we get to here, we need to insist on precise argument matching...
      ParameterInfo[] parameters = method.GetParameters();
      if (this.typeIdentifiers.Count != parameters.Length)
      {
        return false;
      }
      for (int i = 0; i < typeIdentifiers.Count; ++i)
      {
        string identifier = this.typeIdentifiers[i];
        ParameterInfo parameter = parameters[i];
        if (parameter.ParameterType.FullName.IndexOf(identifier) == -1)
        {
          // this parameter cannot match, so neither can the whole override...
          return false;
        }
      }
      return true;
    }

    /// <summary>
    /// A <see cref="System.String"/> that represents the current
    /// <see cref="System.Object"/>.
    /// </summary>
    /// <returns>
    /// A <see cref="System.String"/> that represents the current
    /// <see cref="System.Object"/>.
    /// </returns>
    public override string ToString()
    {
      return new StringBuilder(GetType().Name).Append(" for method '")
        .Append(MethodName).Append("'; will call object '").Append(this.methodReplacerObjectName)
        .Append("'.").ToString();
    }
  }
}