IT. Expert System.

All Implemented Interfaces:

Closeable, AutoCloseable, Readable

Direct Known Subclasses:

BufferedReader, CharArrayReader, FilterReader, InputStreamReader, PipedReader, StringReader

public abstract class Reader
extends Object
implements Readable, Closeable

See Also:

Writer

• Field Summary

  Fields

  Modifier and Type	Field and Description
  protected Object	lock The object used to synchronize access to the reader.

• Constructor Summary

  Constructors

  Modifier	Constructor and Description
  protected	Reader() Constructs a new Reader with this as the object used to synchronize critical sections.
  protected	Reader(Object lock) Constructs a new Reader with lock used to synchronize critical sections.

• Method Summary

  Methods

  Modifier and Type	Method and Description
  abstract void	close() Closes this reader.
  void	mark(int readLimit) Sets a mark position in this reader.
  boolean	markSupported() Indicates whether this reader supports the mark() and reset() methods.
  int	read() Reads a single character from this reader and returns it as an integer with the two higher-order bytes set to 0.
  int	read(char[] buf) Reads characters from this reader and stores them in the character array buf starting at offset 0.
  abstract int	read(char[] buf, int offset, int count) Reads at most count characters from this reader and stores them at offset in the character array buf.
  int	read(CharBuffer target) Reads characters and puts them into the target character buffer.
  boolean	ready() Indicates whether this reader is ready to be read without blocking.
  void	reset() Resets this reader's position to the last mark() location.
  long	skip(long charCount) Skips charCount characters in this reader.

  • Methods inherited from class java.lang.Object

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

• Field Detail

  • lock

    protected Object lock

    The object used to synchronize access to the reader.

• Constructor Detail

  • Reader

    protected Reader()

    Constructs a new Reader with this as the object used to synchronize critical sections.

  • Reader

    protected Reader(Object lock)

    Constructs a new Reader with lock used to synchronize critical sections.

    Parameters:

    lock - the Object used to synchronize critical sections.

    Throws:

    NullPointerException - if lock is null.

• Method Detail

  • close

    public abstract void close()
                        throws IOException

    Closes this reader. Implementations of this method should free any resources associated with the reader.

    Specified by:

    close in interface Closeable

    Specified by:

    close in interface AutoCloseable

    Throws:

    IOException - if an error occurs while closing this reader.

  • mark

    public void mark(int readLimit)
              throws IOException

    Sets a mark position in this reader. The parameter readLimit indicates how many characters can be read before the mark is invalidated. Calling reset() will reposition the reader back to the marked position if readLimit has not been surpassed.

    This default implementation simply throws an IOException; subclasses must provide their own implementation.

    Parameters:

    readLimit - the number of characters that can be read before the mark is invalidated.

    Throws:

    IllegalArgumentException - if readLimit < 0.

    IOException - if an error occurs while setting a mark in this reader.

    See Also:

    markSupported(), reset()

  • markSupported

    public boolean markSupported()

    Indicates whether this reader supports the mark() and reset() methods. This default implementation returns false.

    Returns:

    always false.

  • read

    public int read()
             throws IOException

    Reads a single character from this reader and returns it as an integer with the two higher-order bytes set to 0. Returns -1 if the end of the reader has been reached.

    Returns:

    the character read or -1 if the end of the reader has been reached.

    Throws:

    IOException - if this reader is closed or some other I/O error occurs.

  • read

    public int read(char[] buf)
             throws IOException

    Reads characters from this reader and stores them in the character array buf starting at offset 0. Returns the number of characters actually read or -1 if the end of the reader has been reached.

    Parameters:

    buf - character array to store the characters read.

    Returns:

    the number of characters read or -1 if the end of the reader has been reached.

    Throws:

    IOException - if this reader is closed or some other I/O error occurs.

  • read

    public abstract int read(char[] buf,
           int offset,
           int count)
                      throws IOException

    Reads at most count characters from this reader and stores them at offset in the character array buf. Returns the number of characters actually read or -1 if the end of the reader has been reached.

    Parameters:

    buf - the character array to store the characters read.

    offset - the initial position in buffer to store the characters read from this reader.

    count - the maximum number of characters to read.

    Returns:

    the number of characters read or -1 if the end of the reader has been reached.

    Throws:

    IOException - if this reader is closed or some other I/O error occurs.

  • ready

    public boolean ready()
                  throws IOException

    Indicates whether this reader is ready to be read without blocking. Returns true if this reader will not block when read is called, false if unknown or blocking will occur. This default implementation always returns false.

    Returns:

    always false.

    Throws:

    IOException - if this reader is closed or some other I/O error occurs.

    See Also:

    read(), read(char[]), read(char[], int, int)

  • reset

    public void reset()
               throws IOException

    Resets this reader's position to the last mark() location. Invocations of read() and skip() will occur from this new location. If this reader has not been marked, the behavior of reset() is implementation specific. This default implementation throws an IOException.

    Throws:

    IOException - always thrown in this default implementation.

    See Also:

    mark(int), markSupported()

  • skip

    public long skip(long charCount)
              throws IOException

    Skips charCount characters in this reader. Subsequent calls of read methods will not return these characters unless reset is used. This method may perform multiple reads to read charCount characters.

    Returns:

    the number of characters actually skipped.

    Throws:

    IllegalArgumentException - if charCount < 0.

    IOException - if this reader is closed or some other I/O error occurs.

    See Also:

    mark(int), markSupported(), reset()

  • read

    public int read(CharBuffer target)
             throws IOException

    Reads characters and puts them into the target character buffer.

    Specified by:

    read in interface Readable

    Parameters:

    target - the destination character buffer.

    Returns:

    the number of characters put into target or -1 if the end of this reader has been reached before a character has been read.

    Throws:

    IOException - if any I/O error occurs while reading from this reader.

    NullPointerException - if target is null.

    ReadOnlyBufferException - if target is read-only.