Package db.buffers

Interface ManagedBufferFile

All Superinterfaces:
BufferFile
All Known Implementing Classes:
LocalManagedBufferFile, ManagedBufferFileAdapter
public interface ManagedBufferFile extends BufferFile
BufferFile facilitates read/write access to buffer oriented file. Access to related resources, such as parameters and change data, is also facilitated.

  • Method Details

    • getNextChangeDataFile

      BufferFile getNextChangeDataFile(boolean getFirst) throws IOException
      Get the next change data file which corresponds to this buffer file. This method acts like an iterator which each successive invocation returning the next available file. Null is returned when no more files are available. The invoker is responsible for closing each file returned. It is highly recommended that each file be closed prior to requesting the next file.
      Parameters:
      getFirst - causes the iterator to reset and return the first available file.
      Throws:
      IOException - if an I/O error occurs

    • getSaveChangeDataFile

      BufferFile getSaveChangeDataFile() throws IOException
      Returns a temporary change data buffer file which should be used to store a application-level ChangeSet associated with this new buffer file version. The getSaveFile method must be successfully invoked prior to invoking this method.
      Returns:
      change data file or null if one is not available.
      Throws:
      IOException - if an I/O error occurs

    • getForwardModMapData

      byte[] getForwardModMapData(int oldVersion) throws IOException
      Returns a bit map corresponding to all buffers modified since oldVersion. This identifies all buffers contained within the oldVersion which have been modified during any revision up until this file version. Buffers added since oldVersion are not identified NOTE: The bit mask may identify empty/free buffers within this file version.
      Parameters:
      oldVersion - indicates the older version of this file for which a change map will be returned. This method may only be invoked if this file is at version 2 or higher, has an associated BufferFileManager and the oldVersion related files still exist.
      Returns:
      ModMap buffer change map data
      Throws:
      IOException - if an I/O error occurs

    • getSaveFile

      ManagedBufferFile getSaveFile() throws IOException
      Returns a Save file if available. Returns null if a save can not be performed. This method may block for an extended period of time if the pre-save process has not already completed. This method does not accept a monitor since a remote TaskMonitor does not yet exist.
      Throws:
      IOException - if an I/O error occurs

    • saveCompleted

      void saveCompleted(boolean commit) throws IOException
      After getting the save file, this method must be invoked to terminate the save.
      Parameters:
      commit - if true the save file will be reopened as read-only for update. If false, the save file will be deleted and the object will become invalid.
      Throws:
      IOException

    • canSave

      boolean canSave() throws IOException
      Returns true if a save file is provided for creating a new version of this buffer file.
      Throws:
      IOException - if an I/O error occurs
      See Also:

    • setVersionComment

      void setVersionComment(String comment) throws IOException
      Set the comment which will be associated with this buffer file if saved. The comment must be set prior to invoking close or setReadOnly.
      Parameters:
      comment - comment text
      Throws:
      IOException - if an I/O error occurs

    • getCheckinID

      long getCheckinID() throws IOException
      Returns the checkin ID corresponding to this buffer file. The returned value is only valid if this buffer file has an associated buffer file manager and is either being created (see isReadOnly) or is intended for update (see canSave).
      Throws:
      IOException - if an I/O error occurs