Inheritance diagram for joshua.util.io.LineReader:

Collaboration diagram for joshua.util.io.LineReader:

Public Member Functions
	LineReader (String filename) throws IOException
	LineReader (String filename, boolean show_progress) throws IOException
	LineReader (InputStream in)
int	progress ()
void	close () throws IOException
boolean	ready () throws IOException
String	readLine () throws IOException
Iterator< String >	iterator ()
boolean	hasNext ()
String	next () throws NoSuchElementException
int	lineno ()
void	remove () throws UnsupportedOperationException
int	countLines () throws IOException
Static Public Member Functions
static void	main (String[] args)
Protected Member Functions
void	finalize () throws Throwable
Private Attributes
BufferedReader	reader
ProgressInputStream	rawStream
String	buffer
IOException	error
int	lineno = 0
boolean	display_progress = false
int	progress = 0
Static Private Attributes
static final Charset	FILE_ENCODING = Charset.forName("UTF-8")

Detailed Description

This class provides an Iterator interface to a BufferedReader. This covers the most common use-cases for reading from files without ugly code to check whether we got a line or not.

Author:: wren ng thornton wren@.nosp@m.user.nosp@m.s.sou.nosp@m.rcef.nosp@m.orge..nosp@m.net; Matt Post post@.nosp@m.cs.j.nosp@m.hu.ed.nosp@m.u

Constructor & Destructor Documentation

joshua.util.io.LineReader.LineReader ( String filename ) throws IOException

Opens a file for iterating line by line. The special "-" filename can be used to specify STDIN. GZIP'd files are tested for automatically.

Parameters:

filename the file to be opened ("-" for STDIN)

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joshua.util.io.LineReader.LineReader	(	String	filename,
		boolean	show_progress
	)		throws IOException

joshua.util.io.LineReader.LineReader ( InputStream in )

Wraps an InputStream for iterating line by line. Stream encoding is assumed to be UTF-8.

Member Function Documentation

void joshua.util.io.LineReader.close ( ) throws IOException

This method will close the file handle, and will raise any exceptions that occured during iteration. The method is idempotent, and all calls after the first are no-ops (unless the thread was interrupted or killed). For correctness, you must call this method before the object falls out of scope.

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int joshua.util.io.LineReader.countLines ( ) throws IOException

Iterates over all lines, ignoring their contents, and returns the count of lines. If some lines have already been read, this will return the count of remaining lines. Because no lines will remain after calling this method, we implicitly call close.

Returns:: the number of lines read

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void joshua.util.io.LineReader.finalize ( ) throws Throwable [protected]

We attempt to avoid leaking file descriptors if you fail to call close before the object falls out of scope. However, the language spec makes no guarantees about timeliness of garbage collection. It is a bug to rely on this method to release the resources. Also, the garbage collector will discard any exceptions that have queued up, without notifying the application in any way.

Having a finalizer means the JVM can't do "fast allocation" of LineReader objects (or subclasses). This isn't too important due to disk latency, but may be worth noting.

See also:: Performance Tips; Techniques

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boolean joshua.util.io.LineReader.hasNext ( )

Returns true if the iteration has more elements. (In other words, returns true if next would return an element rather than throwing an exception.)

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Iterator<String> joshua.util.io.LineReader.iterator ( )

Return self as an iterator.

int joshua.util.io.LineReader.lineno ( )

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static void joshua.util.io.LineReader.main ( String[] args ) [static]

Example usage code.

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String joshua.util.io.LineReader.next ( ) throws NoSuchElementException

Return the next line of the file. If an error is encountered, NoSuchElementException is thrown. The actual IOException encountered will be thrown later, when the LineReader is closed. Also if there is no line to be read then NoSuchElementException is thrown.

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int joshua.util.io.LineReader.progress ( )

Chain to the underlying ProgressInputStream.