jdk.io.BufferedReader — clojure-interop/java.io 1.0.5

Reads 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.

->buffered-reader clj

(->buffered-reader in)

(->buffered-reader in sz)

Constructor.

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

in - A Reader - java.io.Reader sz - Input-buffer size - int

throws: java.lang.IllegalArgumentException - If sz <= 0

close clj

(close this)

Description copied from class: Reader

throws: java.io.IOException - If an I/O error occurs

lines clj

(lines this)

Returns a Stream, the elements of which are lines read from this BufferedReader. The Stream is lazily populated, i.e., read only occurs during the terminal stream operation.

The reader must not be operated on during the execution of the terminal stream operation. Otherwise, the result of the terminal stream operation is undefined.

After execution of the terminal stream operation there are no guarantees that the reader will be at a specific position from which to read the next character or line.

If an IOException is thrown when accessing the underlying BufferedReader, it is wrapped in an UncheckedIOException which will be thrown from the Stream method that caused the read to take place. This method will return a Stream if invoked on a BufferedReader that is closed. Any operation on that stream that requires reading from the BufferedReader after it is closed, will cause an UncheckedIOException to be thrown.

returns: a Stream<String> providing the lines of text described by this BufferedReader - java.util.stream.Stream<java.lang.String>

mark clj

(mark this read-ahead-limit)

Marks the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point.

read-ahead-limit - Limit on the number of characters that may be read while still preserving the mark. An attempt to reset the stream after reading characters up to this limit or beyond 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. - int

throws: java.lang.IllegalArgumentException - If readAheadLimit < 0

mark-supported clj

(mark-supported this)

Tells whether this stream supports the mark() operation, which it does.

returns: true if and only if this stream supports the mark operation. - boolean

read clj

(read this)

(read this cbuf off len)

Reads 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:

The specified number of characters have been read,

The read method of the underlying stream returns

-1, indicating end-of-file, or

The ready method of the underlying stream

returns false, indicating that further input requests would block.

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.

cbuf - Destination buffer - char[] off - Offset at which to start storing characters - int len - Maximum number of characters to read - int

returns: The number of characters read, or -1 if the end of the stream has been reached - int

throws: java.io.IOException - If an I/O error occurs

read-line clj

(read-line this)

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

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 - java.lang.String

throws: java.io.IOException - If an I/O error occurs

ready clj

(ready this)

Tells 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.

returns: True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block. - boolean

throws: java.io.IOException - If an I/O error occurs

reset clj

(reset this)

Resets the stream to the most recent mark.

throws: java.io.IOException - If the stream has never been marked, or if the mark has been invalidated

skip clj

(skip this n)

Skips characters.

n - The number of characters to skip - long

returns: The number of characters actually skipped - long

throws: java.lang.IllegalArgumentException - If n is negative.