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JavaTM 2 Platform Std. Ed. v1.3 |
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java.lang.Object
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+--java.io.Reader
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+--java.io.BufferedReader
Read text from a character-input stream, buffering characters so as to provide for the efficient reading of characters, arrays, and lines.
The buffer size may be specified, or the default size may be used. The default is large enough for most purposes.
In general, each read request made of a Reader causes a corresponding read request to be made of the underlying character or byte stream. It is therefore advisable to wrap a BufferedReader around any Reader whose read() operations may be costly, such as FileReaders and InputStreamReaders. For example,
BufferedReader in
= new BufferedReader(new FileReader("foo.in"));
will buffer the input from the specified file. Without buffering, each
invocation of read() or readLine() could cause bytes to be read from the
file, converted into characters, and then returned, which can be very
inefficient.
Programs that use DataInputStreams for textual input can be localized by replacing each DataInputStream with an appropriate BufferedReader.
FileReader,
InputStreamReader| Fields inherited from class java.io.Reader |
lock |
| Constructor Summary | |
BufferedReader(Reader in)
Create a buffering character-input stream that uses a default-sized input buffer. |
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BufferedReader(Reader in,
int sz)
Create a buffering character-input stream that uses an input buffer of the specified size. |
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| Method Summary | |
void |
close()
Close the stream. |
void |
mark(int readAheadLimit)
Mark the present position in the stream. |
boolean |
markSupported()
Tell whether this stream supports the mark() operation, which it does. |
int |
read()
Read a single character. |
int |
read(char[] cbuf,
int off,
int len)
Read characters into a portion of an array. |
String |
readLine()
Read a line of text. |
boolean |
ready()
Tell whether this stream is ready to be read. |
void |
reset()
Reset the stream to the most recent mark. |
long |
skip(long n)
Skip characters. |
| Methods inherited from class java.io.Reader |
read |
| Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
public BufferedReader(Reader in,
int sz)
in - A Readersz - Input-buffer sizeIllegalArgumentException - If sz is <= 0public BufferedReader(Reader in)
in - A Reader| Method Detail |
public int read()
throws IOException
read in class ReaderIOException - If an I/O error occurs
public int read(char[] cbuf,
int off,
int len)
throws IOException
This method implements the general contract of the corresponding
method of the
read class. As an additional convenience, it
attempts to read as many characters as possible by repeatedly invoking
the Readerread method of the underlying stream. This iterated
read continues until one of the following conditions becomes
true:
read method of the underlying stream returns
-1, indicating end-of-file, or
ready method of the underlying stream
returns false, indicating that further input requests
would block.
read on the underlying stream returns
-1 to indicate end-of-file then this method returns
-1. Otherwise this method returns the number of characters
actually read.
Subclasses of this class are encouraged, but not required, to attempt to read as many characters as possible in the same fashion.
Ordinarily this method takes characters from this stream's character
buffer, filling it from the underlying stream as necessary. If,
however, the buffer is empty, the mark is not valid, and the requested
length is at least as large as the buffer, then this method will read
characters directly from the underlying stream into the given array.
Thus redundant BufferedReaders will not copy data
unnecessarily.
read in class Readercbuf - Destination bufferoff - Offset at which to start storing characterslen - Maximum number of characters to readIOException - If an I/O error occurs
public String readLine()
throws IOException
IOException - If an I/O error occurs
public long skip(long n)
throws IOException
skip in class Readern - The number of characters to skipIllegalArgumentException - If n is negative.IOException - If an I/O error occurs
public boolean ready()
throws IOException
ready in class ReaderIOException - If an I/O error occurspublic boolean markSupported()
markSupported in class Readerjava.io.Reader
public void mark(int readAheadLimit)
throws IOException
mark in class ReaderreadAheadLimit - 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. A limit value larger
than the size of the input buffer will cause a
new buffer to be allocated whose size is no
smaller than limit. Therefore large values
should be used with care.IllegalArgumentException - If readAheadLimit is < 0IOException - If an I/O error occurs
public void reset()
throws IOException
reset in class ReaderIOException - If the stream has never been marked,
or if the mark has been invalidated
public void close()
throws IOException
close in class ReaderIOException - If an I/O error occurs
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JavaTM 2 Platform Std. Ed. v1.3 |
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