Class FileByteStore

java.lang.Object
uk.ac.starlink.table.storage.FileByteStore
All Implemented Interfaces:
ByteStore

public class FileByteStore extends Object implements ByteStore
ByteStore implementation which uses a temporary file.
Since:
11 Jul 2008
Author:
Mark Taylor
  • Constructor Summary

    Constructors
    Constructor
    Description
    Constructs a new FileByteStore which uses a temporary file as backing store.
    Constructs a new FileByteStore which uses the given file as a backing store.
  • Method Summary

    Modifier and Type
    Method
    Description
    void
    Tidies up.
    static void
    copy(File file, OutputStream out)
    Utility method to copy the contents of a file to an output stream.
    void
    Takes all the data written so far into this store's sink stream and copies it to a destination stream.
    Returns the file used by this store.
    long
    Returns the number of bytes currently stored in this object.
    Returns an output stream which can be used to write to the store.
    Returns an array of byte buffers containing the bytes written to this store.
    static ByteBuffer[]
    Returns a read-only ByteBuffer array representing the contents of a file, with default maximum buffer length.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Constructor Details

    • FileByteStore

      public FileByteStore(File file) throws IOException
      Constructs a new FileByteStore which uses the given file as a backing store. Nothing is done to mark this file as temporary.
      Parameters:
      file - location of the backing file which will be used
      Throws:
      IOException - if there is some I/O-related problem with opening the file
      SecurityException - if the current security context does not allow writing to a temporary file
    • FileByteStore

      public FileByteStore() throws IOException
      Constructs a new FileByteStore which uses a temporary file as backing store. The temporary file will be written to the default temporary directory, given by the value of the java.io.tmpdir system property.
      Throws:
      IOException - if there is some I/O-related problem with opening the file
      SecurityException - if the current security context does not allow writing to a temporary file
  • Method Details

    • getFile

      public File getFile()
      Returns the file used by this store.
      Returns:
      file
    • getOutputStream

      public OutputStream getOutputStream()
      Description copied from interface: ByteStore
      Returns an output stream which can be used to write to the store. May be called multiple times; always returns the same object. Note that this is not in general buffered - it is the responsibility of the user to take steps like wrapping it in a BufferedOutputStream for efficiency if required.
      Specified by:
      getOutputStream in interface ByteStore
      Returns:
      data sink stream
    • getLength

      public long getLength()
      Description copied from interface: ByteStore
      Returns the number of bytes currently stored in this object.
      Specified by:
      getLength in interface ByteStore
      Returns:
      byte count
    • copy

      public void copy(OutputStream out) throws IOException
      Description copied from interface: ByteStore
      Takes all the data written so far into this store's sink stream and copies it to a destination stream. The output stream is not closed.
      Specified by:
      copy in interface ByteStore
      Parameters:
      out - data destination stream
      Throws:
      IOException
    • toByteBuffers

      public ByteBuffer[] toByteBuffers() throws IOException
      Description copied from interface: ByteStore
      Returns an array of byte buffers containing the bytes written to this store. The stored bytes are all of the bytes from the first buffer in the returned array, followed by all in the second, etc. In many cases the returned array will, and probably should, contain a single buffer, but if the written byte count exceeds Integer.MAX_VALUE, more than one will be required. The limit of each buffer indicates the number of bytes it contains.

      Usual usage will be to write all data, then call this method once; this model may affect implementation decisions about efficiency.

      Specified by:
      toByteBuffers in interface ByteStore
      Returns:
      byte buffer containing bytes written
      Throws:
      IOException - if there is an I/O error
    • copy

      public static void copy(File file, OutputStream out) throws IOException
      Utility method to copy the contents of a file to an output stream. The stream is not closed.
      Parameters:
      file - file
      out - destination stream
      Throws:
      IOException
    • toByteBuffers

      public static ByteBuffer[] toByteBuffers(File file) throws IOException
      Returns a read-only ByteBuffer array representing the contents of a file, with default maximum buffer length. If the file can be represented in a single ByteBuffer the result will be a single-element array; otherwise the concatenation of the buffers in the result gives the file content.
      Parameters:
      file - file
      Returns:
      mapped byte buffers
      Throws:
      IOException
    • close

      public void close()
      Description copied from interface: ByteStore
      Tidies up. Should be called when the data in this object is no longer required. This object may no longer be usable following a call to this method.
      Specified by:
      close in interface ByteStore