forked from XWxiaowei/JavaCode
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathInputStreamReader.java
More file actions
201 lines (186 loc) · 5.53 KB
/
InputStreamReader.java
File metadata and controls
201 lines (186 loc) · 5.53 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
/*
* Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*/
package java.io;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import sun.nio.cs.StreamDecoder;
/**
* An InputStreamReader is a bridge from byte streams to character streams: It
* reads bytes and decodes them into characters using a specified {@link
* java.nio.charset.Charset charset}. The charset that it uses
* may be specified by name or may be given explicitly, or the platform's
* default charset may be accepted.
*
* <p> Each invocation of one of an InputStreamReader's read() methods may
* cause one or more bytes to be read from the underlying byte-input stream.
* To enable the efficient conversion of bytes to characters, more bytes may
* be read ahead from the underlying stream than are necessary to satisfy the
* current read operation.
*
* <p> For top efficiency, consider wrapping an InputStreamReader within a
* BufferedReader. For example:
*
* <pre>
* BufferedReader in
* = new BufferedReader(new InputStreamReader(System.in));
* </pre>
*
* @see BufferedReader
* @see InputStream
* @see java.nio.charset.Charset
*
* @author Mark Reinhold
* @since JDK1.1
*/
public class InputStreamReader extends Reader {
private final StreamDecoder sd;
/**
* Creates an InputStreamReader that uses the default charset.
*
* @param in An InputStream
*/
public InputStreamReader(InputStream in) {
super(in);
try {
sd = StreamDecoder.forInputStreamReader(in, this, (String)null); // ## check lock object
} catch (UnsupportedEncodingException e) {
// The default encoding should always be available
throw new Error(e);
}
}
/**
* Creates an InputStreamReader that uses the named charset.
*
* @param in
* An InputStream
*
* @param charsetName
* The name of a supported
* {@link java.nio.charset.Charset charset}
*
* @exception UnsupportedEncodingException
* If the named charset is not supported
*/
public InputStreamReader(InputStream in, String charsetName)
throws UnsupportedEncodingException
{
super(in);
if (charsetName == null)
throw new NullPointerException("charsetName");
sd = StreamDecoder.forInputStreamReader(in, this, charsetName);
}
/**
* Creates an InputStreamReader that uses the given charset.
*
* @param in An InputStream
* @param cs A charset
*
* @since 1.4
* @spec JSR-51
*/
public InputStreamReader(InputStream in, Charset cs) {
super(in);
if (cs == null)
throw new NullPointerException("charset");
sd = StreamDecoder.forInputStreamReader(in, this, cs);
}
/**
* Creates an InputStreamReader that uses the given charset decoder.
*
* @param in An InputStream
* @param dec A charset decoder
*
* @since 1.4
* @spec JSR-51
*/
public InputStreamReader(InputStream in, CharsetDecoder dec) {
super(in);
if (dec == null)
throw new NullPointerException("charset decoder");
sd = StreamDecoder.forInputStreamReader(in, this, dec);
}
/**
* Returns the name of the character encoding being used by this stream.
*
* <p> If the encoding has an historical name then that name is returned;
* otherwise the encoding's canonical name is returned.
*
* <p> If this instance was created with the {@link
* #InputStreamReader(InputStream, String)} constructor then the returned
* name, being unique for the encoding, may differ from the name passed to
* the constructor. This method will return <code>null</code> if the
* stream has been closed.
* </p>
* @return The historical name of this encoding, or
* <code>null</code> if the stream has been closed
*
* @see java.nio.charset.Charset
*
* @revised 1.4
* @spec JSR-51
*/
public String getEncoding() {
return sd.getEncoding();
}
/**
* Reads a single character.
*
* @return The character read, or -1 if the end of the stream has been
* reached
*
* @exception IOException If an I/O error occurs
*/
public int read() throws IOException {
return sd.read();
}
/**
* Reads characters into a portion of an array.
*
* @param cbuf Destination buffer
* @param offset Offset at which to start storing characters
* @param length Maximum number of characters to read
*
* @return The number of characters read, or -1 if the end of the
* stream has been reached
*
* @exception IOException If an I/O error occurs
*/
public int read(char cbuf[], int offset, int length) throws IOException {
return sd.read(cbuf, offset, length);
}
/**
* Tells whether this stream is ready to be read. An InputStreamReader is
* ready if its input buffer is not empty, or if bytes are available to be
* read from the underlying byte stream.
*
* @exception IOException If an I/O error occurs
*/
public boolean ready() throws IOException {
return sd.ready();
}
public void close() throws IOException {
sd.close();
}
}