| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 |
| * |
| * https://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 Avro.File |
| { |
| /// <summary> |
| /// Defines the interface for an object that reads data from a file. |
| /// </summary> |
| /// <typeparam name="T">Type to serialize data to.</typeparam> |
| public interface IFileReader<T> : IDisposable |
| { |
| /// <summary> |
| /// Return the header for the input file or stream. |
| /// </summary> |
| /// <returns>Parsed header from the file or stream.</returns> |
| Header GetHeader(); |
| |
| /// <summary> |
| /// Return the schema as read from the file or stream. |
| /// </summary> |
| /// <returns>Parse schema from the file or stream.</returns> |
| Schema GetSchema(); |
| |
| /// <summary> |
| /// Return the list of keys in the metadata. |
| /// </summary> |
| /// <returns>Metadata keys from the header of the data file.</returns> |
| ICollection<string> GetMetaKeys(); |
| |
| /// <summary> |
| /// Return an enumeration of the remaining entries in the file. |
| /// </summary> |
| /// <returns>An enumeration of the remaining entries in the file.</returns> |
| IEnumerable<T> NextEntries { get; } |
| |
| /// <summary> |
| /// Read the next datum from the file. |
| /// </summary> |
| /// <returns>Next deserialized data entry.</returns> |
| T Next(); |
| |
| /// <summary> |
| /// Returns true if more entries remain in this file. |
| /// </summary> |
| /// <returns>True if more entries remain in this file, false otherwise.</returns> |
| bool HasNext(); |
| |
| /// <summary> |
| /// Return the byte value of a metadata property. |
| /// </summary> |
| /// <param name="key">Key for the metadata entry.</param> |
| /// <returns>Raw bytes of the value of the metadata entry.</returns> |
| /// <exception cref="KeyNotFoundException"> |
| /// There is no metadata entry with the specified <paramref name="key"/>. |
| /// </exception> |
| byte[] GetMeta(string key); |
| |
| /// <summary> |
| /// Return the long value of a metadata property. |
| /// </summary> |
| /// <param name="key">Key for the metadata entry.</param> |
| /// <returns>Metadata value as a long.</returns> |
| /// <exception cref="KeyNotFoundException"> |
| /// There is no metadata entry with the specified <paramref name="key"/>. |
| /// </exception> |
| long GetMetaLong(string key); |
| |
| /// <summary> |
| /// Return the string value of a metadata property. This method assumes that the string is a |
| /// UTF-8 encoded in the header. |
| /// </summary> |
| /// <param name="key">Key for the metadata entry.</param> |
| /// <returns>Metadata value as a string.</returns> |
| /// <exception cref="KeyNotFoundException"> |
| /// There is no metadata entry with the specified <paramref name="key"/>. |
| /// </exception> |
| /// <exception cref="AvroRuntimeException"> |
| /// Encountered an exception while decoding the value as a UTF-8 string. |
| /// </exception> |
| string GetMetaString(string key); |
| |
| /// <summary> |
| /// Return true if past the next synchronization point after a position. |
| /// </summary> |
| /// <param name="position">Position to test.</param> |
| /// <returns> |
| /// True if path the next synchronization point after <paramref name="position"/>, false |
| /// otherwise. |
| /// </returns> |
| bool PastSync(long position); |
| |
| /// <summary> |
| /// Return the last synchronization point before our current position. |
| /// </summary> |
| /// <returns> |
| /// Position of the last synchronization point before our current position. |
| /// </returns> |
| long PreviousSync(); |
| |
| /// <summary> |
| /// Move to a specific, known synchronization point, |
| /// one returned from <see cref="IFileWriter{T}.Sync"/> while writing. |
| /// </summary> |
| /// <param name="position">Position to jump to.</param> |
| void Seek(long position); |
| |
| /// <summary> |
| /// Move to the next synchronization point after a position. |
| /// </summary> |
| /// <param name="position">Position in the stream to start.</param> |
| void Sync(long position); |
| |
| /// <summary> |
| /// Return the current position in the input. |
| /// </summary> |
| /// <returns>Current position in the input.</returns> |
| long Tell(); |
| } |
| } |