Package org.eclipse.net4j.util.io

Class DelegatingInputStream

java.lang.Object
java.io.InputStream
org.eclipse.net4j.util.io.DelegatingInputStream
All Implemented Interfaces:
Closeable, AutoCloseable
Direct Known Subclasses:
XORInputStream
public class DelegatingInputStream extends InputStream
A DelegatingInputStream contains some other input stream, which it uses as its basic source of data, possibly transforming the data along the way or providing additional functionality. The class DelegatingInputStream itself simply overrides all (see note below) methods of InputStream with versions that pass all requests to the contained input stream. Subclasses of DelegatingInputStream may further override some of these methods and may also provide additional methods and fields.

Note: The only difference to FilterInputStream is that DelegatingInputStream does not override InputStream.read(byte[]) or InputStream.read(byte[], int, int) but rather exposes the original implementations of InputStream which call read() instead of their delegate counterparts.

Author:
Eike Stepper

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected InputStream
    in
    The input stream to be filtered.

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    DelegatingInputStream(InputStream in)
    Creates a DelegatingInputStream by assigning the argument in to the field this.in so as to remember it for later use.

  • 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.
    InputStream
    getDelegate()
     
    void
    mark(int readlimit)
    Marks the current position in this input stream.
    boolean
    markSupported()
    Tests if this input stream supports the mark and reset methods.
    int
    read()
    Reads the next byte of data from this input stream.
    void
    reset()
    Repositions this stream to the position at the time the mark method was last called on this input stream.
    long
    skip(long n)
    Skips over and discards n bytes of data from the input stream.

    Methods inherited from class java.io.InputStream

    nullInputStream, read, read, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo

    Methods inherited from class java.lang.Object

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

  • Field Details

    • in

      protected volatile InputStream in
      The input stream to be filtered.

  • Constructor Details

    • DelegatingInputStream

      protected DelegatingInputStream(InputStream in)
      Creates a DelegatingInputStream by assigning the argument in to the field this.in so as to remember it for later use.
      Parameters:
      in - the underlying input stream, or null if this instance is to be created without an underlying stream.

  • Method Details

    • getDelegate

      public InputStream getDelegate()

    • read

      public int read() throws IOException
      Reads the next byte of data from this input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

      This method simply performs in.read() and returns the result.

      Specified by:
      read in class InputStream
      Returns:
      the next byte of data, or -1 if the end of the stream is reached.
      Throws:
      IOException - if an I/O error occurs.
      See Also:

    • skip

      public long skip(long n) throws IOException
      Skips over and discards n bytes of data from the input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. The actual number of bytes skipped is returned.

      This method simply performs in.skip(n).

      Overrides:
      skip in class InputStream
      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.

      This method simply performs in.available() and returns the result.

      Overrides:
      available in class InputStream
      Returns:
      the number of bytes that can be read from the input stream without blocking.
      Throws:
      IOException - if an I/O error occurs.
      See Also:

    • close

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

    • mark

      public void mark(int readlimit)
      Marks the current position in this input stream. A subsequent call to the reset method repositions this stream at the last marked position so that subsequent reads re-read the same bytes.

      The readlimit argument tells this input stream to allow that many bytes to be read before the mark position gets invalidated.

      This method simply performs in.mark(readlimit).

      Overrides:
      mark in class InputStream
      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
      Repositions this stream to the position at the time the mark method was last called on this input stream.

      This method simply performs in.reset().

      Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parse, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails. If this happens within readlimit bytes, it allows the outer code to reset the stream and try another parser.

      Overrides:
      reset in class InputStream
      Throws:
      IOException - if the 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. This method simply performs in.markSupported().
      Overrides:
      markSupported in class InputStream
      Returns:
      true if this stream type supports the mark and reset method; false otherwise.
      See Also: