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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      */
FilterReader(Reader in)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      */
read()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      */
read(char cbuf[], int off, int len)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      */
skip(long n)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      */
ready()91     public boolean ready() throws IOException {
92         return in.ready();
93     }
94 
95     /**
96      * Tells whether this stream supports the mark() operation.
97      */
markSupported()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      */
mark(int readAheadLimit)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      */
reset()116     public void reset() throws IOException {
117         in.reset();
118     }
119 
close()120     public void close() throws IOException {
121         in.close();
122     }
123 
124 }
125