org.grouplens.lenskit.util

Class LineCursor

java.lang.Object

org.grouplens.lenskit.cursors.AbstractCursor<T>

org.grouplens.lenskit.cursors.AbstractPollingCursor<String>

org.grouplens.lenskit.util.LineCursor

All Implemented Interfaces:

Closeable, AutoCloseable, Iterable<String>, Cursor<String>

public class LineCursor
extends AbstractPollingCursor<String>

Cursor that reads lines from a file.

Since:

0.10

Constructor Summary

Constructors

Constructor and Description
LineCursor(BufferedReader in) Construct a cursor reading lines from a buffered reader.

Method Summary

Modifier and Type	Method and Description
void	close() No-op implementation of the Cursor.close() method.
int	getLineNumber() Return the number of the line returned by the last call to AbstractPollingCursor.next().
static LineCursor	openFile(File file) Open a delimited text cursor as a file.
static LineCursor	openFile(File file, CompressionMode comp) Open a delimited text cursor as a file.
String	poll() Return the next element in this Cursor, or null if there are no more elements.

Methods inherited from class org.grouplens.lenskit.cursors.AbstractPollingCursor

copy, fastNext, hasNext, next

Methods inherited from class org.grouplens.lenskit.cursors.AbstractCursor

fast, getRowCount, iterator

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

LineCursor

public LineCursor(@WillCloseWhenClosed @Nonnull
                  BufferedReader in)

Construct a cursor reading lines from a buffered reader.

Parameters:

in - The input reader.

Method Detail

openFile

public static LineCursor openFile(File file)
                           throws FileNotFoundException

Open a delimited text cursor as a file.

Parameters:

file - The file to open.

Returns:

The cursor.

Throws:

FileNotFoundException - if there is an error opening the file.

openFile

public static LineCursor openFile(File file,
                                  CompressionMode comp)
                           throws IOException

Open a delimited text cursor as a file.

Parameters:

file - The file to open.

Returns:

The cursor.

Throws:

FileNotFoundException - if there is an error opening the file.

IOException

poll

public String poll()

Description copied from class: AbstractPollingCursor

Return the next element in this Cursor, or null if there are no more elements. This must be safe to call multiple times at the end of its collection. The same element object is allowed to be reused (fast iteration), so long as AbstractPollingCursor.copy(Object) copies objects. If this method returns a fresh object every time, then AbstractPollingCursor.copy(Object) should be a no-op.

Specified by:

poll in class AbstractPollingCursor<String>

Returns:

The next element, or null

getLineNumber

public int getLineNumber()

Return the number of the line returned by the last call to AbstractPollingCursor.next().

Returns:

The number of the last line retrieved.

close

public void close()

Description copied from class: AbstractCursor

No-op implementation of the Cursor.close() method.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Cursor<String>

Overrides:

close in class AbstractCursor<String>