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      1 /*
      2  * Copyright (c) 1996, 2005, Oracle and/or its affiliates. All rights reserved.
      3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
      4  *
      5  * This code is free software; you can redistribute it and/or modify it
      6  * under the terms of the GNU General Public License version 2 only, as
      7  * published by the Free Software Foundation.  Oracle designates this
      8  * particular file as subject to the "Classpath" exception as provided
      9  * by Oracle in the LICENSE file that accompanied this code.
     10  *
     11  * This code is distributed in the hope that it will be useful, but WITHOUT
     12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
     13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
     14  * version 2 for more details (a copy is included in the LICENSE file that
     15  * accompanied this code).
     16  *
     17  * You should have received a copy of the GNU General Public License version
     18  * 2 along with this work; if not, write to the Free Software Foundation,
     19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
     20  *
     21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
     22  * or visit www.oracle.com if you need additional information or have any
     23  * questions.
     24  */
     25 
     26 package java.io;
     27 
     28 
     29 /**
     30  * Abstract class for reading filtered character streams.
     31  * The abstract class <code>FilterReader</code> itself
     32  * provides default methods that pass all requests to
     33  * the contained stream. Subclasses of <code>FilterReader</code>
     34  * should override some of these methods and may also provide
     35  * additional methods and fields.
     36  *
     37  * @author      Mark Reinhold
     38  * @since       JDK1.1
     39  */
     40 
     41 public abstract class FilterReader extends Reader {
     42 
     43     /**
     44      * The underlying character-input stream.
     45      */
     46     protected Reader in;
     47 
     48     /**
     49      * Creates a new filtered reader.
     50      *
     51      * @param in  a Reader object providing the underlying stream.
     52      * @throws NullPointerException if <code>in</code> is <code>null</code>
     53      */
     54     protected FilterReader(Reader in) {
     55         super(in);
     56         this.in = in;
     57     }
     58 
     59     /**
     60      * Reads a single character.
     61      *
     62      * @exception  IOException  If an I/O error occurs
     63      */
     64     public int read() throws IOException {
     65         return in.read();
     66     }
     67 
     68     /**
     69      * Reads characters into a portion of an array.
     70      *
     71      * @exception  IOException  If an I/O error occurs
     72      */
     73     public int read(char cbuf[], int off, int len) throws IOException {
     74         return in.read(cbuf, off, len);
     75     }
     76 
     77     /**
     78      * Skips characters.
     79      *
     80      * @exception  IOException  If an I/O error occurs
     81      */
     82     public long skip(long n) throws IOException {
     83         return in.skip(n);
     84     }
     85 
     86     /**
     87      * Tells whether this stream is ready to be read.
     88      *
     89      * @exception  IOException  If an I/O error occurs
     90      */
     91     public boolean ready() throws IOException {
     92         return in.ready();
     93     }
     94 
     95     /**
     96      * Tells whether this stream supports the mark() operation.
     97      */
     98     public boolean markSupported() {
     99         return in.markSupported();
    100     }
    101 
    102     /**
    103      * Marks the present position in the stream.
    104      *
    105      * @exception  IOException  If an I/O error occurs
    106      */
    107     public void mark(int readAheadLimit) throws IOException {
    108         in.mark(readAheadLimit);
    109     }
    110 
    111     /**
    112      * Resets the stream.
    113      *
    114      * @exception  IOException  If an I/O error occurs
    115      */
    116     public void reset() throws IOException {
    117         in.reset();
    118     }
    119 
    120     public void close() throws IOException {
    121         in.close();
    122     }
    123 
    124 }
    125