#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.Runtime.Serialization;
using Spring.Util;
namespace Spring.Expressions{
/// <summary>
/// Represents unary minus operator.
/// </summary>
/// <author>Aleksandar Seovic</author>
[Serializable]
public class OpUnaryMinus : UnaryOperator
{
/// <summary>
/// Create a new instance
/// </summary>
public OpUnaryMinus():base()
{
}
/// <summary>
/// Create a new instance from SerializationInfo
/// </summary>
protected OpUnaryMinus(SerializationInfo info, StreamingContext context)
: base(info, context)
{
}
/// <summary>
/// Returns a value for the unary plus operator 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 n = GetValue(Operand, context, evalContext );
if (!NumberUtils.IsNumber(n))
{
throw new ArgumentException(
"Specified operand is not a number. Only numbers support unary minus operator.");
}
return NumberUtils.Negate(n);
}
}
}
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