Package org.refcodes.filesystem

Interface FileSystem

  • All Superinterfaces:
    org.refcodes.component.Component, org.refcodes.component.Destroyable
    All Known Implementing Classes:
    ChangeRootFileSystemWrapperImpl, InMemoryFileSystemImpl

    public interface FileSystem
extends org.refcodes.component.Component
    A file system represents an abstraction for any "physical" storage medium where file (handles) can be stored and retrieved. The file (handles) are structured in a hierarchy similar to a file system's hierarchy with folders and files. The hierarchy may be completely virtual (the underlying system just knows of "keys" and directories are simulated by key naming conventions), so the underlying physical file system might be an FTP server or an in-memory Map (with virtual files and folders) or a real file system with a real directory and file hierarchy. The file system only contains file (handle)s, any construct such as a "directory" does not exist from the file system's point of view and therefore cannot be created or removed explicitly. Them are created or removed implicitly when file (handles) are created or removed. An implementation for, lets say, a file system, should take care to remove physical folders from the file system when removing a file (handle) (the corresponding file from the file system's folder) in case the folder from which the file (handle) (file) was removed ends up empty! In turn, when creating a file (handle), the corresponding directory structure must be created in case we have a file system with a "file system nature". File (handles) are never instantiated directly, them are retrieved from the file system as them can be implementation specific. A specific file (handle) instance therefore is always attached to a specific instance of a file system. Using file (handle)s interchangeably between tow different file system instances will (usually) fail. A file system and the file (handle)s are a self contained systems similar to the entities of an O/R mapper being attached to a specific persistence provider. Whenever an operation returns a file (handle), this file (handle) is to be considered the actual working copy and to be used in favor to a previous data file (handle) identifying the same data. The returned file (handle) will provide updated information. A file (handle) in the file system is identified by a unique key, which in turn consists of a path and a name. The path and the name are concatenated by a path separator, usually the slash "/". The path itself might be composed with path separators. Having this, a "file system nature" file system can map the file (handle)s to files in a directory hierarchy on the file system. Any path or key being provided is to be normalized by an implementation of the file system (using the FileSystemUtility) by removing any trailing path separators. Illegal paths will cause an IllegalPathException, IllegalNameException or an IllegalKeyException, i.e. path which do not start with a path separator or have two or more subsequent path separators in then or any other illegal characters.

    • Nested Class Summary

      • Nested classes/interfaces inherited from interface org.refcodes.component.Destroyable

        org.refcodes.component.Destroyable.DestroyAutomaton

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static char PATH_DELIMITER
      The default path delimiter to be used by all implementations if this file system to ensure interoperability.

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      FileHandle createFile​(String aKey)
      Creates a file (handle) with the given key.
      FileHandle createFile​(String aPath, String aName)
      Creates a file (handle) with the given path and name.
      void deleteFile​(FileHandle aFileHandle)
      Deletes a file (handle) from the file system.
      InputStream fromFile​(FileHandle aFromFileHandle)
      An input stream is being provided from which the data of the file (handle) may be read.
      void fromFile​(FileHandle aFromFileHandle, File aToFile)
      The data contained in the given file (handle) is written to the provided file.
      void fromFile​(FileHandle aFromFileHandle, OutputStream aOutputStream)
      The data contained in the given file (handle) is written to the provided output stream.
      FileHandle getFileHandle​(String aKey)
      Gets a file (handle) with the given key from the file system.
      FileHandle getFileHandle​(String aPath, String aName)
      Gets a file (handle) with the given path and name from the file system.
      List<FileHandle> getFileHandles​(String aPath, boolean isRecursively)
      With the behavior of the hasFiles(String, boolean) method, all file (handle)s found for the path are returned.
      boolean hasFile​(String aKey)
      Tests whether the file system knows a file (handle) with the given key.
      boolean hasFile​(String aPath, String aName)
      Tests whether the file system knows a file (handle) with the given path and name.
      boolean hasFile​(FileHandle aFileHandle)
      Returns true in case the given file (handle) exists.
      boolean hasFiles​(String aPath, boolean isRecursively)
      Determines whether there is any file (handle)s found for the given path.
      FileHandle moveFile​(FileHandle aFileHandle, String aNewKey)
      Renames the file (handle), it will be accessible via the provided key.
      FileHandle renameFile​(FileHandle aFileHandle, String aNewName)
      Renames the file (handle), the name part of the key will be renamed to the new name.
      OutputStream toFile​(FileHandle aToFileHandle)
      Returns an output stream which may be used to write (or append, in case data did already exist for the file system) data to a file (handle).
      void toFile​(FileHandle aToFileHandle, byte[] aBuffer)
      Data provided by the given buffer is written to the file (handle) (or appended to the file (handle)'s data in case the file (handle) did already contain data).
      void toFile​(FileHandle aToFileHandle, File aFromFile)
      Data provided by the given input stream is written to the file (handle) (or appended to the file (handle)'s data in case the file (handle) did already contain data).
      void toFile​(FileHandle aToFileHandle, InputStream aInputStream)
      Data provided by the given input stream is written to the file (handle) (or appended to the file (handle)'s data in case the file (handle) did already contain data).

      • Methods inherited from interface org.refcodes.component.Destroyable

        destroy