#region Copyright & License

//

// Copyright 2001-2005 The Apache Software Foundation

//

// 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;



namespace log4net.Core

{

    /// <summary>

    /// An evaluator that triggers after specified number of seconds.

    /// </summary>

    /// <remarks>

    /// <para>

    /// This evaluator will trigger if the specified time period 

    /// <see cref="Interval"/> has passed since last check.

    /// </para>

    /// </remarks>

    /// <author>Robert Sevcik</author>

    public class TimeEvaluator : ITriggeringEventEvaluator

    {

        /// <summary>

        /// The time threshold for triggering in seconds. Zero means it won't trigger at all.

        /// </summary>

        private int m_interval;



        /// <summary>

        /// The time of last check. This gets updated when the object is created and when the evaluator triggers.

        /// </summary>

        private DateTime m_lasttime;



        /// <summary>

        /// The default time threshold for triggering in seconds. Zero means it won't trigger at all.

        /// </summary>

        const int DEFAULT_INTERVAL = 0;



        /// <summary>

        /// Create a new evaluator using the <see cref="DEFAULT_INTERVAL"/> time threshold in seconds.

        /// </summary>

        /// <remarks>

        /// <para>

        /// Create a new evaluator using the <see cref="DEFAULT_INTERVAL"/> time threshold in seconds.

        /// </para>

        /// <para>

        /// This evaluator will trigger if the specified time period 

        /// <see cref="Interval"/> has passed since last check.

        /// </para>

        /// </remarks>

        public TimeEvaluator()

            : this(DEFAULT_INTERVAL)

        {

        }



        /// <summary>

        /// Create a new evaluator using the specified time threshold in seconds.

        /// </summary>

        /// <param name="interval">

        /// The time threshold in seconds to trigger after.

        /// Zero means it won't trigger at all.

        /// </param>

        /// <remarks>

        /// <para>

        /// Create a new evaluator using the specified time threshold in seconds.

        /// </para>

        /// <para>

        /// This evaluator will trigger if the specified time period 

        /// <see cref="Interval"/> has passed since last check.

        /// </para>

        /// </remarks>

        public TimeEvaluator(int interval)

        {

            m_interval = interval;

            m_lasttime = DateTime.Now;

        }



        /// <summary>

        /// The time threshold in seconds to trigger after

        /// </summary>

        /// <value>

        /// The time threshold in seconds to trigger after.

        /// Zero means it won't trigger at all.

        /// </value>

        /// <remarks>

        /// <para>

        /// This evaluator will trigger if the specified time period 

        /// <see cref="Interval"/> has passed since last check.

        /// </para>

        /// </remarks>

        public int Interval

        {

            get { return m_interval; }

            set { m_interval = value; }

        }



        /// <summary>

        /// Is this <paramref name="loggingEvent"/> the triggering event?

        /// </summary>

        /// <param name="loggingEvent">The event to check</param>

        /// <returns>This method returns <c>true</c>, if the specified time period 

        /// <see cref="Interval"/> has passed since last check.. 

        /// Otherwise it returns <c>false</c></returns>

        /// <remarks>

        /// <para>

        /// This evaluator will trigger if the specified time period 

        /// <see cref="Interval"/> has passed since last check.

        /// </para>

        /// </remarks>

        public bool IsTriggeringEvent(LoggingEvent loggingEvent)

        {

            if (loggingEvent == null)

            {

                throw new ArgumentNullException("loggingEvent");

            }



            // disable the evaluator if threshold is zero

            if (m_interval == 0) return false;



            lock (this) // avoid triggering multiple times

            {

                TimeSpan passed = DateTime.Now.Subtract(m_lasttime);



                if (passed.TotalSeconds > m_interval)

                {

                    m_lasttime = DateTime.Now;

                    return true;

                }

                else

                {

                    return false;

                }

            }

        }

    }

}