Package javax.mail.util

Class SharedFileInputStream

java.lang.Object
java.io.InputStream
java.io.FilterInputStream
java.io.BufferedInputStream
javax.mail.util.SharedFileInputStream
All Implemented Interfaces:
Closeable, AutoCloseable, SharedInputStream
public class SharedFileInputStream extends BufferedInputStream implements SharedInputStream
A SharedFileInputStream is a BufferedInputStream that buffers data from the file and supports the mark and reset methods. It also supports the newStream method that allows you to create other streams that represent subsets of the file. A RandomAccessFile object is used to access the file data.

Note that when the SharedFileInputStream is closed, all streams created with the newStream method are also closed. This allows the creator of the SharedFileInputStream object to control access to the underlying file and ensure that it is closed when needed, to avoid leaking file descriptors. Note also that this behavior contradicts the requirements of SharedInputStream and may change in a future release.

Since:
JavaMail 1.4

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected long
    bufpos
    The file offset that corresponds to the first byte in the read buffer.
    protected int
    bufsize
    The normal size of the read buffer.
    protected long
    datalen
    The amount of data in this subset of the file.
    protected RandomAccessFile
    in
    The file containing the data.
    protected long
    start
    The file offset of the start of data in this subset of the file.

    Fields inherited from class java.io.BufferedInputStream

    buf, count, marklimit, markpos, pos

  • Constructor Summary

    Constructors
    Constructor
    Description
    SharedFileInputStream(File file)
    Creates a SharedFileInputStream for the file.
    SharedFileInputStream(File file, int size)
    Creates a SharedFileInputStream with the specified buffer size.
    SharedFileInputStream(String file)
    Creates a SharedFileInputStream for the named file
    SharedFileInputStream(String file, int size)
    Creates a SharedFileInputStream with the specified buffer size.

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    available()
    Returns the number of bytes that can be read from this input stream without blocking.
    void
    close()
    Closes this input stream and releases any system resources associated with the stream.
    protected void
    finalize()
    Force this stream to close.
    long
    getPosition()
    Return the current position in the InputStream, as an offset from the beginning of the InputStream.
    void
    mark(int readlimit)
    See the general contract of the mark method of InputStream.
    boolean
    markSupported()
    Tests if this input stream supports the mark and reset methods.
    InputStream
    newStream(long start, long end)
    Return a new InputStream representing a subset of the data from this InputStream, starting at start (inclusive) up to end (exclusive).
    int
    read()
    See the general contract of the read method of InputStream.
    int
    read(byte[] b, int off, int len)
    Reads bytes from this stream into the specified byte array, starting at the given offset.
    void
    reset()
    See the general contract of the reset method of InputStream.
    long
    skip(long n)
    See the general contract of the skip method of InputStream.

    Methods inherited from class java.io.FilterInputStream

    read

    Methods inherited from class java.io.InputStream

    nullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo

    Methods inherited from class java.lang.Object

    clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • in

      protected RandomAccessFile in
      The file containing the data. Shared by all related SharedFileInputStreams.

    • bufsize

      protected int bufsize
      The normal size of the read buffer.

    • bufpos

      protected long bufpos
      The file offset that corresponds to the first byte in the read buffer.

    • start

      protected long start
      The file offset of the start of data in this subset of the file.

    • datalen

      protected long datalen
      The amount of data in this subset of the file.

  • Constructor Details

    • SharedFileInputStream

      public SharedFileInputStream(File file) throws IOException
      Creates a SharedFileInputStream for the file.
      Parameters:
      file - the file
      Throws:
      IOException

    • SharedFileInputStream

      public SharedFileInputStream(String file) throws IOException
      Creates a SharedFileInputStream for the named file
      Parameters:
      file - the file
      Throws:
      IOException

    • SharedFileInputStream

      public SharedFileInputStream(File file, int size) throws IOException
      Creates a SharedFileInputStream with the specified buffer size.
      Parameters:
      file - the file
      size - the buffer size.
      Throws:
      IllegalArgumentException - if size <= 0.
      IOException

    • SharedFileInputStream

      public SharedFileInputStream(String file, int size) throws IOException
      Creates a SharedFileInputStream with the specified buffer size.
      Parameters:
      file - the file
      size - the buffer size.
      Throws:
      IllegalArgumentException - if size <= 0.
      IOException

  • Method Details

    • read

      public int read() throws IOException
      See the general contract of the read method of InputStream.
      Overrides:
      read in class BufferedInputStream
      Returns:
      the next byte of data, or -1 if the end of the stream is reached.
      Throws:
      IOException - if an I/O error occurs.

    • read

      public int read(byte[] b, int off, int len) throws IOException
      Reads bytes from this stream into the specified byte array, starting at the given offset.

      This method implements the general contract of the corresponding read method of the InputStream class.

      Overrides:
      read in class BufferedInputStream
      Parameters:
      b - destination buffer.
      off - offset at which to start storing bytes.
      len - maximum number of bytes to read.
      Returns:
      the number of bytes read, or -1 if the end of the stream has been reached.
      Throws:
      IOException - if an I/O error occurs.

    • skip

      public long skip(long n) throws IOException
      See the general contract of the skip method of InputStream.
      Overrides:
      skip in class BufferedInputStream
      Parameters:
      n - the number of bytes to be skipped.
      Returns:
      the actual number of bytes skipped.
      Throws:
      IOException - if an I/O error occurs.

    • available

      public int available() throws IOException
      Returns the number of bytes that can be read from this input stream without blocking.
      Overrides:
      available in class BufferedInputStream
      Returns:
      the number of bytes that can be read from this input stream without blocking.
      Throws:
      IOException - if an I/O error occurs.

    • mark

      public void mark(int readlimit)
      See the general contract of the mark method of InputStream.
      Overrides:
      mark in class BufferedInputStream
      Parameters:
      readlimit - the maximum limit of bytes that can be read before the mark position becomes invalid.
      See Also:

    • reset

      public void reset() throws IOException
      See the general contract of the reset method of InputStream.

      If markpos is -1 (no mark has been set or the mark has been invalidated), an IOException is thrown. Otherwise, pos is set equal to markpos.

      Overrides:
      reset in class BufferedInputStream
      Throws:
      IOException - if this stream has not been marked or if the mark has been invalidated.
      See Also:

    • markSupported

      public boolean markSupported()
      Tests if this input stream supports the mark and reset methods. The markSupported method of SharedFileInputStream returns true.
      Overrides:
      markSupported in class BufferedInputStream
      Returns:
      a boolean indicating if this stream type supports the mark and reset methods.
      See Also:

    • close

      public void close() throws IOException
      Closes this input stream and releases any system resources associated with the stream.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Overrides:
      close in class BufferedInputStream
      Throws:
      IOException - if an I/O error occurs.

    • getPosition

      public long getPosition()
      Return the current position in the InputStream, as an offset from the beginning of the InputStream.
      Specified by:
      getPosition in interface SharedInputStream
      Returns:
      the current position

    • newStream

      public InputStream newStream(long start, long end)
      Return a new InputStream representing a subset of the data from this InputStream, starting at start (inclusive) up to end (exclusive). start must be non-negative. If end is -1, the new stream ends at the same place as this stream. The returned InputStream will also implement the SharedInputStream interface.
      Specified by:
      newStream in interface SharedInputStream
      Parameters:
      start - the starting position
      end - the ending position + 1
      Returns:
      the new stream

    • finalize

      protected void finalize() throws Throwable
      Force this stream to close.
      Overrides:
      finalize in class Object
      Throws:
      Throwable