Module jakarta.mail
Package jakarta.mail.util

Class SharedFileInputStream

  • All Implemented Interfaces:
    SharedInputStream, java.io.Closeable, java.lang.AutoCloseable
    public class SharedFileInputStream
extends java.io.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.

    Author:
    Bill Shannon

    • 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 java.io.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​(java.io.File file)
      Creates a SharedFileInputStream for the file.
      SharedFileInputStream​(java.io.File file, int size)
      Creates a SharedFileInputStream with the specified buffer size.
      SharedFileInputStream​(java.lang.String file)
      Creates a SharedFileInputStream for the named file
      SharedFileInputStream​(java.lang.String file, int size)
      Creates a SharedFileInputStream with the specified buffer size.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      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.
      java.io.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, transferTo

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • in

        protected java.io.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 Detail

      • SharedFileInputStream

        public SharedFileInputStream​(java.io.File file)
                      throws java.io.IOException
        Creates a SharedFileInputStream for the file.
        Parameters:
        file - the file
        Throws:
        java.io.IOException - for errors opening the file

      • SharedFileInputStream

        public SharedFileInputStream​(java.lang.String file)
                      throws java.io.IOException
        Creates a SharedFileInputStream for the named file
        Parameters:
        file - the file
        Throws:
        java.io.IOException - for errors opening the file

      • SharedFileInputStream

        public SharedFileInputStream​(java.io.File file,
                             int size)
                      throws java.io.IOException
        Creates a SharedFileInputStream with the specified buffer size.
        Parameters:
        file - the file
        size - the buffer size.
        Throws:
        java.io.IOException - for errors opening the file
        java.lang.IllegalArgumentException - if size ≤ 0.

      • SharedFileInputStream

        public SharedFileInputStream​(java.lang.String file,
                             int size)
                      throws java.io.IOException
        Creates a SharedFileInputStream with the specified buffer size.
        Parameters:
        file - the file
        size - the buffer size.
        Throws:
        java.io.IOException - for errors opening the file
        java.lang.IllegalArgumentException - if size ≤ 0.

    • Method Detail

      • read

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

      • read

        public int read​(byte[] b,
                int off,
                int len)
         throws java.io.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 java.io.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:
        java.io.IOException - if an I/O error occurs.

      • skip

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

      • available

        public int available()
              throws java.io.IOException
        Returns the number of bytes that can be read from this input stream without blocking.
        Overrides:
        available in class java.io.BufferedInputStream
        Returns:
        the number of bytes that can be read from this input stream without blocking.
        Throws:
        java.io.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 java.io.BufferedInputStream
        Parameters:
        readlimit - the maximum limit of bytes that can be read before the mark position becomes invalid.
        See Also:
        reset()

      • reset

        public void reset()
           throws java.io.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 java.io.BufferedInputStream
        Throws:
        java.io.IOException - if this stream has not been marked or if the mark has been invalidated.
        See Also:
        mark(int)

      • 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 java.io.BufferedInputStream
        Returns:
        a boolean indicating if this stream type supports the mark and reset methods.
        See Also:
        InputStream.mark(int), InputStream.reset()

      • close

        public void close()
           throws java.io.IOException
        Closes this input stream and releases any system resources associated with the stream.
        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        Overrides:
        close in class java.io.BufferedInputStream
        Throws:
        java.io.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 java.io.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 java.lang.Throwable
        Force this stream to close.
        Overrides:
        finalize in class java.lang.Object
        Throws:
        java.lang.Throwable