Module java.base
Package java.io

Class FilterOutputStream

java.lang.Object
java.io.OutputStream
java.io.FilterOutputStream
All Implemented Interfaces:
Closeable, Flushable, AutoCloseable
Direct Known Subclasses:
BufferedOutputStream, CheckedOutputStream, CipherOutputStream, DataOutputStream, DeflaterOutputStream, DigestOutputStream, InflaterOutputStream, PrintStream
public class FilterOutputStream extends OutputStream
This class is the superclass of all classes that filter output streams. These streams sit on top of an already existing output stream (the underlying output stream) which it uses as its basic sink of data, but possibly transforming the data along the way or providing additional functionality.

The class FilterOutputStream itself simply overrides all methods of OutputStream with versions that pass all requests to the underlying output stream. Subclasses of FilterOutputStream may further override some of these methods as well as provide additional methods and fields.

Since:
1.0

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected OutputStream
    out
    The underlying output stream to be filtered.

  • Constructor Summary

    Constructors
    Constructor
    Description
    FilterOutputStream​(OutputStream out)
    Creates an output stream filter built on top of the specified underlying output stream.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    close()
    Closes this output stream and releases any system resources associated with the stream.
    void
    flush()
    Flushes this output stream and forces any buffered output bytes to be written out to the stream.
    void
    write​(byte[] b)
    Writes b.length bytes to this output stream.
    void
    write​(byte[] b, int off, int len)
    Writes len bytes from the specified byte array starting at offset off to this output stream.
    void
    write​(int b)
    Writes the specified byte to this output stream.

    Methods declared in class java.io.OutputStream

    nullOutputStream

    Methods declared in class java.lang.Object

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

  • Field Details

    • out

      protected OutputStream out
      The underlying output stream to be filtered.

  • Constructor Details

    • FilterOutputStream

      public FilterOutputStream​(OutputStream out)
      Creates an output stream filter built on top of the specified underlying output stream.
      Parameters:
      out - the underlying output stream to be assigned to the field this.out for later use, or null if this instance is to be created without an underlying stream.

  • Method Details

    • write

      public void write​(int b) throws IOException
      Writes the specified byte to this output stream.

      The write method of FilterOutputStream calls the write method of its underlying output stream, that is, it performs out.write(b).

      Implements the abstract write method of OutputStream.

      Specified by:
      write in class OutputStream
      Parameters:
      b - the byte.
      Throws:
      IOException - if an I/O error occurs.

    • write

      public void write​(byte[] b) throws IOException
      Writes b.length bytes to this output stream.

      The write method of FilterOutputStream calls its write method of three arguments with the arguments b, 0, and b.length.

      Note that this method does not call the one-argument write method of its underlying output stream with the single argument b.

      Overrides:
      write in class OutputStream
      Parameters:
      b - the data to be written.
      Throws:
      IOException - if an I/O error occurs.
      See Also:
      write(byte[], int, int)

    • write

      public void write​(byte[] b, int off, int len) throws IOException
      Writes len bytes from the specified byte array starting at offset off to this output stream.

      The write method of FilterOutputStream calls the write method of one argument on each byte to output.

      Note that this method does not call the write method of its underlying output stream with the same arguments. Subclasses of FilterOutputStream should provide a more efficient implementation of this method.

      Overrides:
      write in class OutputStream
      Parameters:
      b - the data.
      off - the start offset in the data.
      len - the number of bytes to write.
      Throws:
      IOException - if an I/O error occurs.
      See Also:
      write(int)

    • flush

      public void flush() throws IOException
      Flushes this output stream and forces any buffered output bytes to be written out to the stream.

      The flush method of FilterOutputStream calls the flush method of its underlying output stream.

      Specified by:
      flush in interface Flushable
      Overrides:
      flush in class OutputStream
      Throws:
      IOException - if an I/O error occurs.
      See Also:
      out

    • close

      public void close() throws IOException
      Closes this output stream and releases any system resources associated with the stream.

      When not already closed, the close method of FilterOutputStream calls its flush method, and then calls the close method of its underlying output stream.

      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Overrides:
      close in class OutputStream
      Throws:
      IOException - if an I/O error occurs.
      See Also:
      flush(), out