﻿//
//   Copyright 2015 Blu Age Corporation - Plano, Texas
//
//   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.Generic;

namespace Summer.Batch.Extra.Sort
{
    /// <summary>
    /// Interface that abstracts a record reader.
    /// </summary>
    /// <typeparam name="T">&nbsp;the type of the records</typeparam>
    public interface IRecordReader<out T> : IDisposable
    {
        /// <summary>
        /// Reads a record.
        /// </summary>
        /// <returns>the read record, or <c>null</c> if the end has been reached</returns>
        T Read();

        /// <summary>
        /// Reads the header.
        /// </summary>
        /// <param name="headerSize">the size of the header</param>
        /// <returns>the header as a list of records</returns>
        IEnumerable<T> ReadHeader(int headerSize);
    }
}