BufferedReader (Java SE 9 & JDK 9 ) (original) (raw)
Constructor Detail
* #### BufferedReader
public BufferedReader([Reader](../../java/io/Reader.html "class in java.io") in,
int sz)
Creates a buffering character-input stream that uses an input buffer of the specified size.
Parameters:
`in` \- A Reader
`sz` \- Input-buffer size
Throws:
`[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- If `sz <= 0`
* #### BufferedReader
public BufferedReader([Reader](../../java/io/Reader.html "class in java.io") in)
Creates a buffering character-input stream that uses a default-sized input buffer.
Parameters:
`in` \- A Reader
Method Detail
* #### read
public int read()
throws [IOException](../../java/io/IOException.html "class in java.io")
Reads a single character.
Overrides:
`[read](../../java/io/Reader.html#read--)` in class `[Reader](../../java/io/Reader.html "class in java.io")`
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
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- If an I/O error occurs
* #### read
public int read(char[] cbuf,
int off,
int len)
throws [IOException](../../java/io/IOException.html "class in java.io")
Reads characters into a portion of an array.
This method implements the general contract of the corresponding`[read](../../java/io/Reader.html#read-char:A-int-int-)` method of the`[Reader](../../java/io/Reader.html "class in java.io")` 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 `BufferedReader`s will not copy data unnecessarily.
Specified by:
`[read](../../java/io/Reader.html#read-char:A-int-int-)` in class `[Reader](../../java/io/Reader.html "class in java.io")`
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
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- If an I/O error occurs
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- If an I/O error occurs
* #### readLine
public [String](../../java/lang/String.html "class in java.lang") readLine()
throws [IOException](../../java/io/IOException.html "class in java.io")
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:
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](../../java/io/IOException.html "class in java.io")` \- If an I/O error occurs
See Also:
[Files.readAllLines(java.nio.file.Path, java.nio.charset.Charset)](../../java/nio/file/Files.html#readAllLines-java.nio.file.Path-java.nio.charset.Charset-)
* #### skip
public long skip(long n)
throws [IOException](../../java/io/IOException.html "class in java.io")
Skips characters.
Overrides:
`[skip](../../java/io/Reader.html#skip-long-)` in class `[Reader](../../java/io/Reader.html "class in java.io")`
Parameters:
`n` \- The number of characters to skip
Returns:
The number of characters actually skipped
Throws:
`[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- If `n` is negative.
`[IOException](../../java/io/IOException.html "class in java.io")` \- If an I/O error occurs
* #### ready
public boolean ready()
throws [IOException](../../java/io/IOException.html "class in java.io")
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.
Overrides:
`[ready](../../java/io/Reader.html#ready--)` in class `[Reader](../../java/io/Reader.html "class in java.io")`
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.
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- If an I/O error occurs
* #### markSupported
public boolean markSupported()
Tells whether this stream supports the mark() operation, which it does.
Overrides:
`[markSupported](../../java/io/Reader.html#markSupported--)` in class `[Reader](../../java/io/Reader.html "class in java.io")`
Returns:
true if and only if this stream supports the mark operation.
* #### mark
public void mark(int readAheadLimit)
throws [IOException](../../java/io/IOException.html "class in java.io")
Marks the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point.
Overrides:
`[mark](../../java/io/Reader.html#mark-int-)` in class `[Reader](../../java/io/Reader.html "class in java.io")`
Parameters:
`readAheadLimit` \- 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](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- If `readAheadLimit < 0`
`[IOException](../../java/io/IOException.html "class in java.io")` \- If an I/O error occurs
* #### reset
public void reset()
throws [IOException](../../java/io/IOException.html "class in java.io")
Resets the stream to the most recent mark.
Overrides:
`[reset](../../java/io/Reader.html#reset--)` in class `[Reader](../../java/io/Reader.html "class in java.io")`
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- If the stream has never been marked, or if the mark has been invalidated
* #### close
public void close()
throws [IOException](../../java/io/IOException.html "class in java.io")
Description copied from class: `[Reader](../../java/io/Reader.html#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.
Specified by:
`[close](../../java/lang/AutoCloseable.html#close--)` in interface `[AutoCloseable](../../java/lang/AutoCloseable.html "interface in java.lang")`
Specified by:
`[close](../../java/io/Closeable.html#close--)` in interface `[Closeable](../../java/io/Closeable.html "interface in java.io")`
Specified by:
`[close](../../java/io/Reader.html#close--)` in class `[Reader](../../java/io/Reader.html "class in java.io")`
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- If an I/O error occurs
* #### lines
public [Stream](../../java/util/stream/Stream.html "interface in java.util.stream")<[String](../../java/lang/String.html "class in java.lang")> lines()
Returns a `Stream`, the elements of which are lines read from this `BufferedReader`. The [Stream](../../java/util/stream/Stream.html "interface in java.util.stream") is lazily populated, i.e., read only occurs during the[terminal stream operation](../util/stream/package-summary.html#StreamOps).
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](../../java/io/IOException.html "class in java.io") is thrown when accessing the underlying`BufferedReader`, it is wrapped in an [UncheckedIOException](../../java/io/UncheckedIOException.html "class in java.io") 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`
Since:
1.8