Added in API level 1

Summary: Inherited Fields | Ctors | Methods | Inherited Methods

BufferedReader

public class BufferedReader
extends Reader

java.lang.Object
↳	java.io.Reader
	↳	java.io.BufferedReader

Known direct subclasses

LineNumberReader

LineNumberReader A buffered character-input stream that keeps track of line numbers.

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.

See also:

Summary

Inherited fields

From class java.io.Reader


    protected
    
    
    Object

lock

The object used to synchronize operations on this stream.

Public constructors
`BufferedReader(Reader in)` Creates a buffering character-input stream that uses a default-sized input buffer.
`BufferedReader(Reader in, int sz)` Creates a buffering character-input stream that uses an input buffer of the specified size.

Public methods
`void`	`close()` Closes the stream and releases any system resources associated with it.
`Stream<String>`	`lines()` Returns a `Stream`, the elements of which are lines read from this `BufferedReader`.
`void`	`mark(int readAheadLimit)` Marks the present position in the stream.
`boolean`	`markSupported()` Tells whether this stream supports the mark() operation, which it does.
`int`	`read()` Reads a single character.
`int`	`read(char[] cbuf, int off, int len)` Reads characters into a portion of an array.
`String`	`readLine()` Reads a line of text.
`boolean`	`ready()` Tells whether this stream is ready to be read.
`void`	`reset()` Resets the stream to the most recent mark.
`long`	`skip(long n)` Skips characters.

Inherited methods

From class


        
          java.io.Reader

`abstract void`	`close()` Closes the stream and releases any system resources associated with it.
`void`	`mark(int readAheadLimit)` Marks the present position in the stream.
`boolean`	`markSupported()` Tells whether this stream supports the mark() operation.
`static Reader`	`nullReader()` Returns a new `Reader` that reads no characters.
`int`	`read()` Reads a single character.
`abstract int`	`read(char[] cbuf, int off, int len)` Reads characters into a portion of an array.
`int`	`read(char[] cbuf)` Reads characters into an array.
`int`	`read(CharBuffer target)` Attempts to read characters into the specified character buffer.
`boolean`	`ready()` Tells whether this stream is ready to be read.
`void`	`reset()` Resets the stream.
`long`	`skip(long n)` Skips characters.
`long`	`transferTo(Writer out)` Reads all characters from this reader and writes the characters to the given writer in the order that they are read.

From class


        
          java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

From interface


        
          java.io.Closeable


      close()

Closes this stream and releases any system resources associated with it.

From interface


        
          java.lang.Readable


      read(CharBuffer cb)

Attempts to read characters into the specified character buffer.

From interface


        
          java.lang.AutoCloseable


      close()

Closes this resource, relinquishing any underlying resources.

Public constructors

BufferedReader

Added in API level 1

public BufferedReader (Reader in)

Creates a buffering character-input stream that uses a default-sized input buffer.

Parameters
`in`	`Reader`: A Reader

BufferedReader

Added in API level 1

public BufferedReader (Reader in, 
                int sz)

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

Parameters
`in`	`Reader`: A Reader
`sz`	`int`: Input-buffer size

Throws
`IllegalArgumentException`	If `sz <= 0`

Public methods

close

Added in API level 1

public void close ()

Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), ready(), mark(), reset(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect.

Throws
`IOException`

lines

Added in API level 24

public Stream<String> lines ()

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
`Stream<String>`	a `Stream<String>` providing the lines of text described by this `BufferedReader`

mark

Added in API level 1

public void mark (int readAheadLimit)

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

Parameters
`readAheadLimit`	`int`: 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.

Throws
`IllegalArgumentException`	If `readAheadLimit < 0`
`IOException`	If an I/O error occurs

markSupported

Added in API level 1

public boolean markSupported ()

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

Returns
`boolean`	true if and only if this stream supports the mark operation.

read

Added in API level 1

public int read ()

Reads a single character.

Returns
`int`	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

Throws
`IOException`	If an I/O error occurs

read

Added in API level 1

public int read (char[] cbuf, 
                int off, 
                int 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.

Parameters
`cbuf`	`char`: Destination buffer
`off`	`int`: Offset at which to start storing characters
`len`	`int`: Maximum number of characters to read

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

Throws
`IOException`	If an I/O error occurs
`IndexOutOfBoundsException`

readLine

Added in API level 1

public String readLine ()

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

Returns
`String`	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 without reading any characters

Throws
`IOException`	If an I/O error occurs

See also:

Files.readAllLines(Path)

ready

Added in API level 1

public boolean ready ()

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
`boolean`	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.

Throws
`IOException`	If an I/O error occurs

reset

Added in API level 1

public void reset ()

Resets the stream to the most recent mark.

Throws
`IOException`	If the stream has never been marked, or if the mark has been invalidated

skip

Added in API level 1

public long skip (long n)

Skips characters.

Parameters
`n`	`long`: The number of characters to skip

Returns
`long`	The number of characters actually skipped

Throws
`IllegalArgumentException`	If `n` is negative.
`IOException`	If an I/O error occurs