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FilterReader
  public
  
  
  abstract
  class
  FilterReader
  
  
  
  
    extends Reader
  
  
  
  
  
  
  
    
      
        
          Known direct subclasses
          
  
  
    
  
  
    
      
        | PushbackReader | 
        
          A character-stream reader that allows characters to be pushed back into the
 stream. 
          
    
         | 
       
      
    
   
   
         
       | 
    
  
  
  
    
  Abstract class for reading filtered character streams.
 The abstract class FilterReader itself
 provides default methods that pass all requests to
 the contained stream. Subclasses of FilterReader
 should override some of these methods and may also provide
 additional methods and fields.
Summary
Fields | 
  
    
    protected
    
    
    Reader | 
    
      in
      The underlying character-input stream.
      
    
 
     | 
  
  
Public methods | 
  
  
  
    
        
        
        
        
        
        void
     | 
  
    
      
      close()
      
      
        Closes the stream and releases any system resources associated with
 it.
        
    
 
      
     | 
  
  
  
  
  
    
        
        
        
        
        
        void
     | 
  
    
      
      mark(int readAheadLimit)
      
      
        Marks the present position in the stream.
        
    
 
      
     | 
  
  
  
  
  
    
        
        
        
        
        
        boolean
     | 
  
    
      
      markSupported()
      
      
        Tells whether this stream supports the mark() operation.
        
    
 
      
     | 
  
  
  
  
  
    
        
        
        
        
        
        int
     | 
  
    
      
      read()
      
      
        Reads a single character.
        
    
 
      
     | 
  
  
  
  
  
    
        
        
        
        
        
        int
     | 
  
    
      
      read(char[] cbuf, int off, int len)
      
      
        Reads characters into a portion of an array.
        
    
 
      
     | 
  
  
  
  
  
    
        
        
        
        
        
        boolean
     | 
  
    
      
      ready()
      
      
        Tells whether this stream is ready to be read.
        
    
 
      
     | 
  
  
  
  
  
    
        
        
        
        
        
        void
     | 
  
    
      
      reset()
      
      
        Resets the stream.
        
    
 
      
     | 
  
  
  
  
  
    
        
        
        
        
        
        long
     | 
  
    
      
      skip(long n)
      
      
        Skips characters.
        
    
 
      
     | 
  
  
Inherited methods | 
  
    From class
      
        
          java.io.Reader
        
      
    
    
      
  
  
  
    
        abstract
        
        
        
        
        void
     | 
  
    
      
      close()
      
      
        Closes the stream and releases any system resources associated with
 it.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        
        
        void
     | 
  
    
      
      mark(int readAheadLimit)
      
      
        Marks the present position in the stream.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        
        
        boolean
     | 
  
    
      
      markSupported()
      
      
        Tells whether this stream supports the mark() operation.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        static
        
        
        Reader
     | 
  
    
      
      nullReader()
      
      
        Returns a new Reader that reads no characters.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        
        
        int
     | 
  
    
      
      read()
      
      
        Reads a single character.
        
    
 
      
     | 
   
  
  
  
  
    
        abstract
        
        
        
        
        int
     | 
  
    
      
      read(char[] cbuf, int off, int len)
      
      
        Reads characters into a portion of an array.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        
        
        int
     | 
  
    
      
      read(char[] cbuf)
      
      
        Reads characters into an array.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        
        
        int
     | 
  
    
      
      read(CharBuffer target)
      
      
        Attempts to read characters into the specified character buffer.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        
        
        boolean
     | 
  
    
      
      ready()
      
      
        Tells whether this stream is ready to be read.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        
        
        void
     | 
  
    
      
      reset()
      
      
        Resets the stream.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        
        
        long
     | 
  
    
      
      skip(long n)
      
      
        Skips characters.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        
        
        long
     | 
  
    
      
      transferTo(Writer out)
      
      
        Reads all characters from this reader and writes the characters to the
 given writer in the order that they are read.
        
    
 
      
     | 
   
  
     
   
 | 
  
    From class
      
        
          java.lang.Object
        
      
    
    
      
  
  
  
    
        
        
        
        
        
        Object
     | 
  
    
      
      clone()
      
      
        Creates and returns a copy of this object.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        
        
        boolean
     | 
  
    
      
      equals(Object obj)
      
      
        Indicates whether some other object is "equal to" this one.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        
        
        void
     | 
  
    
      
      finalize()
      
      
        Called by the garbage collector on an object when garbage collection
 determines that there are no more references to the object.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        final
        
        Class<?>
     | 
  
    
      
      getClass()
      
      
        Returns the runtime class of this Object.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        
        
        int
     | 
  
    
      
      hashCode()
      
      
        Returns a hash code value for the object.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        final
        
        void
     | 
  
    
      
      notify()
      
      
        Wakes up a single thread that is waiting on this object's
 monitor.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        final
        
        void
     | 
  
    
      
      notifyAll()
      
      
        Wakes up all threads that are waiting on this object's monitor.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        
        
        String
     | 
  
    
      
      toString()
      
      
        Returns a string representation of the object.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        final
        
        void
     | 
  
    
      
      wait(long timeoutMillis, int nanos)
      
      
        Causes the current thread to wait until it is awakened, typically
 by being notified or interrupted, or until a
 certain amount of real time has elapsed.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        final
        
        void
     | 
  
    
      
      wait(long timeoutMillis)
      
      
        Causes the current thread to wait until it is awakened, typically
 by being notified or interrupted, or until a
 certain amount of real time has elapsed.
        
    
 
      
     | 
   
  
  
  
  
    
        
        
        
        final
        
        void
     | 
  
    
      
      wait()
      
      
        Causes the current thread to wait until it is awakened, typically
 by being notified or interrupted.
        
    
 
      
     | 
   
  
     
   
 | 
  
    From interface
      
        
          java.io.Closeable
        
      
    
    
      
  
  
  
    
        abstract
        
        
        
        
        void
     | 
  
    
      
      close()
      
      
        Closes this stream and releases any system resources associated
 with it.
        
    
 
      
     | 
   
  
     
   
 | 
| 
  
 | 
| 
  
 | 
Fields
    in
    
protected Reader in
    
    
    
  The underlying character-input stream.
    
 
Protected constructors
    FilterReader
    
protected FilterReader (Reader in)
    
    
    
  Creates a new filtered reader.
    
    | Parameters | 
      
        in | 
        
          Reader: a Reader object providing the underlying stream. | 
      
    
      
  
 
Public methods
    close
    
public void close ()
    
    
    
  Closes the stream and releases any system resources associated with
 it.  Once the stream has been closed, further read(), ready(),
 mark(), reset(), or skip() invocations will throw an IOException.
 Closing a previously closed stream has no effect.
      
  
 
    mark
    
public void mark (int readAheadLimit)
    
    
    
  Marks the present position in the stream.
    
    | Parameters | 
      
        readAheadLimit | 
        
          int: Limit on the number of characters that may be
                         read while still preserving the mark.  After
                         reading this many characters, attempting to
                         reset the stream may fail. | 
      
    
      
  
 
    markSupported
    
public boolean markSupported ()
    
    
    
  Tells whether this stream supports the mark() operation.
    
      | Returns | 
      
        boolean | 
        true if and only if this stream supports the mark operation. | 
      
    
 
    read
    
public int read ()
    
    
    
  Reads a single character.
    
      | Returns | 
      
        int | 
        The character read, as an integer in the range 0 to 65535
             (0x00-0xffff), or -1 if the end of the stream has
             been reached | 
      
    
      
  
 
    read
    
public int read (char[] cbuf, 
                int off, 
                int len)
    
    
    
  Reads characters into a portion of an array.
    
    | Parameters | 
      
        cbuf | 
        
          char: Destination buffer | 
      
      
        off | 
        
          int: Offset at which to start storing characters | 
      
      
        len | 
        
          int: Maximum number of characters to read | 
      
    
    
      | Returns | 
      
        int | 
        The number of characters read, or -1 if the end of the
             stream has been reached | 
      
    
      
  
 
    ready
    
public boolean ready ()
    
    
    
  Tells whether this stream is ready to be read.
    
      | Returns | 
      
        boolean | 
        True if the next read() is guaranteed not to block for input,
 false otherwise.  Note that returning false does not guarantee that the
 next read will block. | 
      
    
      
  
 
    reset
    
public void reset ()
    
    
    
  Resets the stream.
      
  
 
    skip
    
public long skip (long n)
    
    
    
  Skips characters.
    
    | Parameters | 
      
        n | 
        
          long: The number of characters to skip | 
      
    
    
      | Returns | 
      
        long | 
        The number of characters actually skipped | 
      
    
      
  
 
 
 
  
  
    
  
 
  
    
    
      
       
    
    
  
  
  Content and code samples on this page are subject to the licenses described in the Content License. Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
  Last updated 2025-02-10 UTC.
  
  
  
    
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