it.unimi.dsi.io.FastBufferedReader

All Implemented Interfaces:: WordReader, Closeable, Serializable, AutoCloseable, Readable

Direct Known Subclasses:: DelimitedWordReader

public class FastBufferedReader
extends Reader
implements WordReader

A lightweight, unsynchronised buffered reader based on mutable strings.

This class provides buffering for readers, but it does so with purposes and an internal logic that are radically different from the ones adopted in BufferedReader.

There is no support for marking. All methods are unsychronised. All methods returning strings do so by writing in a given MutableString.

Note that instances of this class can wrap an array or a mutable string. In this case, instances of this class may be used as a lightweight, unsynchronised alternative to CharArrayReader providing additional services such as word and line breaking.

As any WordReader, this class is serialisable. The only field kept is the current buffer size, which will be used to rebuild a fast buffered reader with the same buffer size. All other fields will be reset.

Reading words

This class implements WordReader in the simplest way: words are defined as maximal subsequences of characters satisfying Character.isLetterOrDigit(char). To alter this behaviour, you have two choices:

you can provide at construction time a CharSet of characters that will be considered word constituents besides those accepted by Character.isLetterOrDigit(char);
you can override the method isWordConstituent(char); in this case, you must override the copy() method, too.

The second approach is of course more flexible, but the first one is particularly useful from the command line as there is a constructor accepting the additional word constituents as a string.

See Also:: Serialized Form

Field Summary

Fields
Modifier and Type	Field	Description
`protected int`	`avail`	The number of buffer bytes available starting from `pos`.
`protected char[]`	`buffer`	The internal buffer.
`protected int`	`bufferSize`	The buffer size (must be equal to `buffer.length`).
`static int`	`DEFAULT_BUFFER_SIZE`	The default size of the internal buffer in bytes (16Ki).
`protected int`	`pos`	The current position in the buffer.
`protected Reader`	`reader`	The underlying reader.
`static long`	`serialVersionUID`
`protected CharSet`	`wordConstituents`	A set of additional characters that will be considered as word constituents, beside those accepted by `Character.isLetterOrDigit(int)`.

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors
Constructor	Description
`FastBufferedReader()`	Creates a new fast buffered reader with a buffer of `DEFAULT_BUFFER_SIZE` characters.
`FastBufferedReader(char[] array)`	Creates a new fast buffered reader by wrapping a given character array.
`FastBufferedReader(char[] array, int offset, int length)`	Creates a new fast buffered reader by wrapping a given fragment of a character array.
`FastBufferedReader(char[] array, int offset, int length, CharSet wordConstituents)`	Creates a new fast buffered reader by wrapping a given fragment of a character array and using a set of additional word constituents.
`FastBufferedReader(char[] array, CharSet wordConstituents)`	Creates a new fast buffered reader by wrapping a given character array and using a set of additional word constituents.
`FastBufferedReader(int bufferSize)`	Creates a new fast buffered reader with a given buffer size.
`FastBufferedReader(int bufferSize, CharSet wordConstituents)`	Creates a new fast buffered reader with a given buffer size and set of additional word constituents.
`FastBufferedReader(CharSet wordConstituents)`	Creates a new fast buffered reader with a buffer of `DEFAULT_BUFFER_SIZE` characters and given set of additional word constituents.
`FastBufferedReader(MutableString s)`	Creates a new fast buffered reader by wrapping a given mutable string.
`FastBufferedReader(MutableString s, CharSet wordConstituents)`	Creates a new fast buffered reader by wrapping a given mutable string and using a set of additional word constituents.
`FastBufferedReader(Reader r)`	Creates a new fast buffered reader by wrapping a given reader with a buffer of `DEFAULT_BUFFER_SIZE` characters.
`FastBufferedReader(Reader r, int bufferSize)`	Creates a new fast buffered reader by wrapping a given reader with a given buffer size.
`FastBufferedReader(Reader r, int bufferSize, CharSet wordConstituents)`	Creates a new fast buffered reader by wrapping a given reader with a given buffer size and using a set of additional word constituents.
`FastBufferedReader(Reader r, CharSet wordConstituents)`	Creates a new fast buffered reader by wrapping a given reader with a buffer of `DEFAULT_BUFFER_SIZE` characters and using a set of additional word constituents.
`FastBufferedReader(String wordConstituents)`	Creates a new fast buffered reader with a buffer of `DEFAULT_BUFFER_SIZE` characters and a set of additional word constituents specified by a string.
`FastBufferedReader(String bufferSize, String wordConstituents)`	Creates a new fast buffered reader with a given buffer size and a set of additional word constituents, both specified by strings.

Method Summary

Modifier and Type	Method	Description
`void`	`close()`
`FastBufferedReader`	`copy()`	Returns a copy of this word reader.
`protected boolean`	`isWordConstituent(char c)`	Returns whether the given character is a word constituent.
`boolean`	`next(MutableString word, MutableString nonWord)`	Extracts the next word and non-word.
`protected boolean`	`noMoreCharacters()`	Checks whether no more characters will be returned.
`int`	`read()`
`int`	`read(char[] b, int offset, int length)`
`MutableString`	`readLine(MutableString s)`	Reads a line into the given mutable string.
`FastBufferedReader`	`setReader(Reader reader)`	Resets the internal state of this word reader, which will start again reading from the given reader.
`long`	`skip(long n)`
`String`	`toSpec()`
`String`	`toString()`

Methods inherited from class java.io.Reader

mark, markSupported, nullReader, read, read, ready, reset, transferTo

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details
- serialVersionUID
  
  public static final long serialVersionUID
  
  See Also:
  
  Constant Field Values
- DEFAULT_BUFFER_SIZE
  
  public static final int DEFAULT_BUFFER_SIZE
  
  The default size of the internal buffer in bytes (16Ki).
  
  See Also:
  
  Constant Field Values
- bufferSize
  
  protected final int bufferSize
  
  The buffer size (must be equal to buffer.length).
- wordConstituents
  
  protected final CharSet wordConstituents
  
  A set of additional characters that will be considered as word constituents, beside those accepted by Character.isLetterOrDigit(int).
- buffer
  
  protected transient char[] buffer
  
  The internal buffer.
- pos
  
  protected transient int pos
  
  The current position in the buffer.
- avail
  
  protected transient int avail
  
  The number of buffer bytes available starting from pos.
- reader
  
  protected transient Reader reader
  
  The underlying reader.
Constructor Details
- FastBufferedReader
  
  public FastBufferedReader(int bufferSize)
  
  Creates a new fast buffered reader with a given buffer size. The wrapped reader will have to be set later using setReader(Reader).
  
  Parameters:
  
  bufferSize - the size in characters of the internal buffer (must be nonzero).
- FastBufferedReader
  
  public FastBufferedReader(int bufferSize, CharSet wordConstituents)
  
  Creates a new fast buffered reader with a given buffer size and set of additional word constituents. The wrapped reader will have to be set later using setReader(Reader).
  
  Parameters:
  
  bufferSize - the size in characters of the internal buffer (must be nonzero).
  
  wordConstituents - a set of characters that will be considered word constituents.
- FastBufferedReader
  
  public FastBufferedReader()
  
  Creates a new fast buffered reader with a buffer of DEFAULT_BUFFER_SIZE characters. The wrapped reader will have to be set later using setReader(Reader).
- FastBufferedReader
  
  public FastBufferedReader(CharSet wordConstituents)
  
  Creates a new fast buffered reader with a buffer of DEFAULT_BUFFER_SIZE characters and given set of additional word constituents. The wrapped reader will have to be set later using setReader(Reader).
  
  Parameters:
  
  wordConstituents - a set of characters that will be considered word constituents.
- FastBufferedReader
  
  public FastBufferedReader(String wordConstituents)
  
  Creates a new fast buffered reader with a buffer of DEFAULT_BUFFER_SIZE characters and a set of additional word constituents specified by a string.
  Warning: it is easy to mistake this method for one whose semantics is the same as FastBufferedReader(MutableString), that is, wrapping the argument string in a reader.
  
  Parameters:
  
  wordConstituents - a string of characters that will be considered word constituents.
  
  Throws:
  
  IllegalArgumentException - if wordConstituents contains duplicate characters.
- FastBufferedReader
  
  public FastBufferedReader(String bufferSize, String wordConstituents)
  
  Creates a new fast buffered reader with a given buffer size and a set of additional word constituents, both specified by strings.
  
  Parameters:
  
  bufferSize - the size in characters of the internal buffer (must be nonzero).
  
  wordConstituents - a string of characters that will be considered word constituents.
- FastBufferedReader
  
  public FastBufferedReader(Reader r, int bufferSize)
  
  Creates a new fast buffered reader by wrapping a given reader with a given buffer size.
  
  Parameters:
  
  r - a reader to wrap.
  
  bufferSize - the size in bytes of the internal buffer.
- FastBufferedReader
  
  public FastBufferedReader(Reader r, int bufferSize, CharSet wordConstituents)
  
  Creates a new fast buffered reader by wrapping a given reader with a given buffer size and using a set of additional word constituents.
  
  Parameters:
  
  r - a reader to wrap.
  
  bufferSize - the size in characters of the internal buffer (must be nonzero).
  
  wordConstituents - a set of characters that will be considered word constituents.
- FastBufferedReader
  
  public FastBufferedReader(Reader r)
  
  Creates a new fast buffered reader by wrapping a given reader with a buffer of DEFAULT_BUFFER_SIZE characters.
  
  Parameters:
  
  r - a reader to wrap.
- FastBufferedReader
  
  public FastBufferedReader(Reader r, CharSet wordConstituents)
  
  Creates a new fast buffered reader by wrapping a given reader with a buffer of DEFAULT_BUFFER_SIZE characters and using a set of additional word constituents.
  
  Parameters:
  
  r - a reader to wrap.
  
  wordConstituents - a set of characters that will be considered word constituents.
- FastBufferedReader
  
  public FastBufferedReader(char[] array, int offset, int length, CharSet wordConstituents)
  
  Creates a new fast buffered reader by wrapping a given fragment of a character array and using a set of additional word constituents.
  The effect of setReader(Reader) on a buffer created with this constructor is undefined.
  
  Parameters:
  
  array - the array that will be wrapped by the reader.
  
  offset - the first character to be used.
  
  length - the number of character to be used.
  
  wordConstituents - a set of characters that will be considered word constituents.
- FastBufferedReader
  
  public FastBufferedReader(char[] array, int offset, int length)
  
  Creates a new fast buffered reader by wrapping a given fragment of a character array.
  The effect of setReader(Reader) on a buffer created with this constructor is undefined.
  
  Parameters:
  
  array - the array that will be wrapped by the reader.
  
  offset - the first character to be used.
  
  length - the number of character to be used.
- FastBufferedReader
  
  public FastBufferedReader(char[] array, CharSet wordConstituents)
  
  Creates a new fast buffered reader by wrapping a given character array and using a set of additional word constituents.
  The effect of setReader(Reader) on a buffer created with this constructor is undefined.
  
  Parameters:
  
  array - the array that will be wrapped by the reader.
  
  wordConstituents - a set of characters that will be considered word constituents.
- FastBufferedReader
  
  public FastBufferedReader(char[] array)
  
  Creates a new fast buffered reader by wrapping a given character array.
  The effect of setReader(Reader) on a buffer created with this constructor is undefined.
  
  Parameters:
  
  array - the array that will be wrapped by the reader.
- FastBufferedReader
  
  public FastBufferedReader(MutableString s, CharSet wordConstituents)
  
  Creates a new fast buffered reader by wrapping a given mutable string and using a set of additional word constituents.
  The effect of setReader(Reader) on a buffer created with this constructor is undefined.
  
  Parameters:
  
  s - the mutable string that will be wrapped by the reader.
  
  wordConstituents - a set of characters that will be considered word constituents.
- FastBufferedReader
  
  public FastBufferedReader(MutableString s)
  
  Creates a new fast buffered reader by wrapping a given mutable string.
  The effect of setReader(Reader) on a buffer created with this constructor is undefined.
  
  Parameters:
  
  s - the mutable string that will be wrapped by the reader.
Method Details
- copy
  
  public FastBufferedReader copy()
  
  Description copied from interface: WordReader
  
  Returns a copy of this word reader.
  This method must return a word reader with a behaviour that matches exactly that of this word reader.
  
  Specified by:
  
  copy in interface WordReader
  
  Returns:
  
  a copy of this word reader.
- noMoreCharacters
  
  protected boolean noMoreCharacters() throws IOException
  
  Checks whether no more characters will be returned.
  
  Returns:
  
  true if there are no characters in the internal buffer and the underlying reader is exhausted.
  
  Throws:
  
  IOException
- read
  
  public int read() throws IOException
  
  Overrides:
  
  read in class Reader
  
  Throws:
  
  IOException
- read
  
  public int read(char[] b, int offset, int length) throws IOException
  
  Specified by:
  
  read in class Reader
  
  Throws:
  
  IOException
- readLine
  
  public MutableString readLine(MutableString s) throws IOException
  
  Reads a line into the given mutable string.
  The next line of input (defined as in BufferedReader.readLine()) will be stored into s. Note that if s is not loose this method will be quite inefficient.
  
  Parameters:
  
  s - a mutable string that will be used to store the next line (which could be empty).
  
  Returns:
  
  s, or null if the end of file was found, in which case s is unchanged.
  
  Throws:
  
  IOException
- isWordConstituent
  
  protected boolean isWordConstituent(char c)
  
  Returns whether the given character is a word constituent.
  The behaviour of this FastBufferedReader as a WordReader can be radically changed by overwriting this method.
  
  Parameters:
  
  c - a character.
  
  Returns:
  
  whether c should be considered a word constituent.
- next
  
  public boolean next(MutableString word, MutableString nonWord) throws IOException
  
  Description copied from interface: WordReader
  
  Extracts the next word and non-word.
  If this method returns true, a new non-empty word, and possibly a new non-word, have been extracted. It is acceptable that the first call to this method after creation or after a call to WordReader.setReader(Reader) returns an empty word. In other words both word and nonWord are maximal.
  
  Specified by:
  
  next in interface WordReader
  
  Parameters:
  
  word - the next word returned by the underlying reader.
  
  nonWord - the nonword following the next word returned by the underlying reader.
  
  Returns:
  
  true if a new word was processed, false otherwise (in which case both word and nonWord are unchanged).
  
  Throws:
  
  IOException
- setReader
  
  public FastBufferedReader setReader(Reader reader)
  
  Description copied from interface: WordReader
  
  Resets the internal state of this word reader, which will start again reading from the given reader.
  
  Specified by:
  
  setReader in interface WordReader
  
  Parameters:
  
  reader - the new reader providing characters.
  
  Returns:
  
  this word reader.
- skip
  
  public long skip(long n) throws IOException
  
  Overrides:
  
  skip in class Reader
  
  Throws:
  
  IOException
- close
  
  public void close() throws IOException
  
  Specified by:
  
  close in interface AutoCloseable
  
  Specified by:
  
  close in interface Closeable
  
  Specified by:
  
  close in class Reader
  
  Throws:
  
  IOException
- toSpec
  
  public String toSpec()
- toString
  
  public String toString()
  
  Overrides:
  
  toString in class Object

Class FastBufferedReader