# com.google.appengine.api.files
Date: 2012-02-24

## Package com.google.appengine.api.files

Interface Summary
FileReadChannel: An `ReadableByteChannel` for reading bytes from an `AppEngineFile`.
FileService: This is the interface for interacting with the Google App Engine File Service.
FileWriteChannel: An `WritableByteChannel` for appending bytes to an `AppEngineFile`.
RecordReadChannel: A channel for reading records from a `FileReadChannel`.
RecordWriteChannel: A `WritableByteChannel` for writing records to an `FileWriteChannel`.

Class Summary
AppEngineFile: An `AppEngineFile` represents a file in one of the Google App Engine file systems.
Crc32c: This class generates a CRC32C checksum, defined by rfc3720 section B.4.
FileServiceFactory: A factory for producing instances of `FileService`.
GSFileOptions: Container class for holding options for creating Google Storage files.
GSFileOptions.GSFileOptionsBuilder: A builder of GSFileOptions.

Enum Summary
AppEngineFile.FileSystem: Represents the back-end storage location of a file.

Exception Summary
FinalizationException: An `Exception` that indicates that a file is in the wrong finalization state.
KeyOrderingException: A `KeyOrderingException` is thrown by the method `FileWriteChannel.write(ByteBuffer, String)` if the `sequenceKey` parameter is not `null` and the backend system already has recorded a last good sequence key for the file and `sequenceKey` is not lexicographically strictly greater than the last good sequence key.
LockException: An exception that indicates one of two possible cases: An exclusive lock on a file is held by a different App Engine request and so the file may not be accessed in this request This request is trying to acquire an exclusive lock on a file but the file is already opened in a different App Engine request