/* Copyright (c) 2006 Google Inc.
*
* 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.
*/
using System;
using System.Collections;
using System.Text;
using System.Xml;
using Google.GData.Client;
namespace Google.GData.Extensions{
/// <summary>
/// Extensible enum type used in many places.
/// </summary>
public abstract class EnumConstruct : IExtensionElement
{
/// <summary>
/// constructor
/// </summary>
/// <param name="enumType">the type used to initialize</param>
protected EnumConstruct(string enumType)
{
this.enumType = enumType;
readOnly = false;
}
/// <summary>
/// Creates a new EnumConstruct instance with a specific type and value.
/// When this constructor is used the instance has a constant value and
/// may not be modified by the setValue() API.
/// </summary>
/// <param name="enumType">the type used to initialize</param>
/// <param name="initialValue">the initial value of the type</param>
protected EnumConstruct(string enumType, string initialValue)
{
this.enumType = enumType;
this.value = initialValue;
readOnly = true;
}
/// <summary>
/// Construct value cannot be changed
/// </summary>
private bool readOnly;
/// <summary>
/// holds the enumType property
/// </summary>
protected string enumType = null;
/// <summary>
/// Accessor Method for the enumType
/// </summary>
public string Type
{
get { return enumType; }
}
/// <summary>
/// String Value
/// </summary>
protected string value;
/// <summary>
/// Accessor Method for the value
/// </summary>
public string Value
{
get { return value; }
set
{
if (readOnly)
{
throw new ArgumentException(enumType + " instance is read only");
}
this.value = value;
}
}
/// <summary>
/// Equal operator overload
/// </summary>
/// <param name="o">the object to compare to</param>
/// <returns>bool</returns>
public bool equals(Object o)
{
//
// Two EnumConstant instances are considered equal of they are of the
// same concrete subclass and have the same type/value strings. If
// a subtype adds additional member elements that effect the equivalence
// test, it *must* override this implemention.
//
if (o == null || !this.GetType().Equals(o.GetType()))
{
return false;
}
EnumConstruct ec = (EnumConstruct)o;
return Type.Equals(ec.Type) && value.Equals(ec.value);
}
#region overloaded for persistence
//////////////////////////////////////////////////////////////////////
/// <summary>Returns the constant representing this XML element.</summary>
//////////////////////////////////////////////////////////////////////
public string XmlName
{
get { return Type; }
}
/// <summary>
/// Persistence method for the EnumConstruct object
/// </summary>
/// <param name="writer">the xmlwriter to write into</param>
public void Save(XmlWriter writer)
{
if (Utilities.IsPersistable(this.value))
{
writer.WriteStartElement(BaseNameTable.gDataPrefix, XmlName, BaseNameTable.gNamespace);
writer.WriteAttributeString("value", this.value);
writer.WriteEndElement();
}
}
#endregion
}
}
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