java::io::BufferedReader Class Reference

Inheritance diagram for java::io::BufferedReader:

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java::lang::Objectjava::lang::Interfacejava::io::Reader
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Collaboration diagram for java::io::BufferedReader:

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java::lang::Objectjava::lang::Interfacejava::lang::ObjectRefjava::io::Readerjava::lang::Comparable
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List of all members.


Detailed Description

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.

Version:
1.28, 01/12/03
Author:
Mark Reinhold
Since:
JDK1.1

Public Member Functions

 BufferedReader (const Ref< Reader > &in=0, jint size=8192)
 Create a buffering character-input stream that uses an input buffer of the specified size.
virtual jint read ()
 Read a single character.
virtual jint read (Array< jchar > &b, jint off=0, jint len=-1)
 Read characters into a portion of an array.
virtual Ref< StringreadLine (jboolean ignoreLF=false)
 Read a line of text.
virtual jlong skip (jlong n)
 Skip characters.
virtual jboolean ready ()
 Tell whether this stream is ready to be read.
virtual void close ()
 Close the stream.
virtual void mark (jint readlimit=0)
 Mark the present position in the stream.
virtual void reset ()
 Reset the stream to the most recent mark.
virtual jboolean markSupported ()
 Tell whether this stream supports the mark() operation.

Constructor & Destructor Documentation

java::io::BufferedReader::BufferedReader ( const Ref< Reader > &  in = 0,
jint  size = 8192 
)

Create a buffering character-input stream that uses an input buffer of the specified size.

Parameters:
in A Reader
size Input-buffer size
Exceptions:
IllegalArgumentException If sz is <= 0


Member Function Documentation

virtual jint java::io::BufferedReader::read (  )  [virtual]

Read a single character.

Returns:
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
Exceptions:
IOException If an I/O error occurs

Implements java::io::Reader.

virtual jint java::io::BufferedReader::read ( Array< jchar > &  b,
jint  off = 0,
jint  len = -1 
) [virtual]

Read characters into a portion of an array.

This method implements the general contract of the corresponding read method of the Reader class. As an additional convenience, it attempts to read as many characters as possible by repeatedly invoking the read method of the underlying stream. This iterated read continues until one of the following conditions becomes true:

If the first 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.

Parameters:
cbuf Destination buffer
off Offset at which to start storing characters
len Maximum number of characters to read
Returns:
The number of characters read, or -1 if the end of the stream has been reached
Exceptions:
IOException If an I/O error occurs

Implements java::io::Reader.

virtual Ref<String> java::io::BufferedReader::readLine ( jboolean  ignoreLF = false  )  [virtual]

Read a line of text.

A line is considered to be terminated by any one of a line feed ('
'), a carriage return (''), or a carriage return followed immediately by a linefeed.

Parameters:
ignoreLF If true, the next '
' will be skipped
Returns:
A String containing the contents of the line, not including any line-termination characters, or null if the end of the stream has been reached
See also:
java.io.LineNumberReader::readLine()
Exceptions:
IOException If an I/O error occurs

virtual jlong java::io::BufferedReader::skip ( jlong  n  )  [virtual]

Skip characters.

Parameters:
n The number of characters to skip
Returns:
The number of characters actually skipped
Exceptions:
IllegalArgumentException If n is negative.
IOException If an I/O error occurs

Implements java::io::Reader.

virtual jboolean java::io::BufferedReader::ready (  )  [virtual]

Tell whether this stream is ready to be read.

A buffered character stream is ready if the buffer is not empty, or if the underlying character stream is ready.

Exceptions:
IOException If an I/O error occurs

Reimplemented from java::io::Reader.

virtual void java::io::BufferedReader::close (  )  [virtual]

Close the stream.

Exceptions:
IOException If an I/O error occurs

Reimplemented from java::io::Reader.

virtual void java::io::BufferedReader::mark ( jint  readlimit = 0  )  [virtual]

Mark the present position in the stream.

Subsequent calls to reset() will attempt to reposition the stream to this point.

Parameters:
readAheadLimit 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.
Exceptions:
IllegalArgumentException If readAheadLimit is < 0
IOException If an I/O error occurs

Reimplemented from java::io::Reader.

virtual void java::io::BufferedReader::reset (  )  [virtual]

Reset the stream to the most recent mark.

Exceptions:
IOException If the stream has never been marked, or if the mark has been invalidated

Reimplemented from java::io::Reader.

virtual jboolean java::io::BufferedReader::markSupported (  )  [virtual]

Tell whether this stream supports the mark() operation.

Reimplemented from java::io::Reader.


The documentation for this class was generated from the following file:
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