Class Reader

java.lang.Object
java.io.Reader
All Implemented Interfaces:
AutoCloseable
Direct Known Subclasses:
CharArrayReader, InputStreamReader, StringReader, StringReader
public abstract class Reader extends Object implements AutoCloseable
Abstract class for reading character streams. The only methods that a subclass must implement are read(char[], int, int) and close(). Most subclasses, however, will override some of the methods defined here in order to provide higher efficiency, additional functionality, or both. Since: JDK1.1, CLDC 1.0 See Also:InputStreamReader, Writer

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected Object
    lock
    The object used to synchronize operations on this stream.

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    Reader()
    Create a new character-stream reader whose critical sections will synchronize on the reader itself.
    protected
    Reader(Object lock)
    Create a new character-stream reader whose critical sections will synchronize on the given object.

  • Method Summary

    Modifier and Type
    Method
    Description
    abstract void
    close()
    Close the stream.
    void
    mark(int readAheadLimit)
    Mark the present position in the stream.
    boolean
    markSupported()
    Tell whether this stream supports the mark() operation.
    int
    read()
    Read a single character.
    int
    read(char[] cbuf)
    Read characters into an array.
    abstract int
    read(char[] cbuf, int off, int len)
    Read characters into a portion of an array.
    boolean
    ready()
    Tell whether this stream is ready to be read.
    void
    reset()
    Reset the stream.
    long
    skip(long n)
    Skip characters.

    Methods inherited from class Object

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

  • Field Details

    • lock

      protected Object lock
      The object used to synchronize operations on this stream. For efficiency, a character-stream object may use an object other than itself to protect critical sections. A subclass should therefore use the object in this field rather than this or a synchronized method.

  • Constructor Details

    • Reader

      protected Reader()
      Create a new character-stream reader whose critical sections will synchronize on the reader itself.

    • Reader

      protected Reader(Object lock)
      Create a new character-stream reader whose critical sections will synchronize on the given object. lock - The Object to synchronize on.

  • Method Details

    • close

      public abstract void close() throws IOException
      Close the stream. Once a stream has been closed, further read(), ready(), mark(), or reset() invocations will throw an IOException. Closing a previously-closed stream, however, has no effect.
      Specified by:
      close in interface AutoCloseable
      Throws:
      IOException

    • mark

      public void mark(int readAheadLimit) throws IOException
      Mark the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point. Not all character-input streams support the mark() operation.
      Throws:
      IOException

    • markSupported

      public boolean markSupported()
      Tell whether this stream supports the mark() operation. The default implementation always returns false. Subclasses should override this method.

    • read

      public int read() throws IOException
      Read a single character. This method will block until a character is available, an I/O error occurs, or the end of the stream is reached. Subclasses that intend to support efficient single-character input should override this method.
      Throws:
      IOException

    • read

      public int read(char[] cbuf) throws IOException
      Read characters into an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.
      Throws:
      IOException

    • read

      public abstract int read(char[] cbuf, int off, int len) throws IOException
      Read characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.
      Throws:
      IOException

    • ready

      public boolean ready() throws IOException
      Tell whether this stream is ready to be read.
      Throws:
      IOException

    • reset

      public void reset() throws IOException
      Reset the stream. If the stream has been marked, then attempt to reposition it at the mark. If the stream has not been marked, then attempt to reset it in some way appropriate to the particular stream, for example by repositioning it to its starting point. Not all character-input streams support the reset() operation, and some support reset() without supporting mark().
      Throws:
      IOException

    • skip

      public long skip(long n) throws IOException
      Skip characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached.
      Throws:
      IOException