edu.stanford.nlp.io

Class RecordIterator

java.lang.Object

edu.stanford.nlp.io.RecordIterator

All Implemented Interfaces:

java.util.Iterator<java.util.List<java.lang.String>>

public class RecordIterator
extends java.lang.Object
implements java.util.Iterator<java.util.List<java.lang.String>>

For reading files or input streams which are structured as records and fields (rows and columns). Each time you call next(), you get back the next record as a list of strings. You can specify the field delimiter (as a regular expression), how many fields to expect, and whether to filter lines containing the wrong number of fields. The iterator may be empty, if the file is empty. If there is an IOException when next() is called, it is caught silently, and null is returned (!).

Author:

Bill MacCartney

Constructor Summary

Constructors

Constructor and Description
RecordIterator(java.io.InputStream in) Returns an Iterator over records (lists of strings) corresponding to lines in the specified InputStream.
RecordIterator(java.io.InputStream in, int fields, boolean filter, java.lang.String delim) Returns an Iterator over records (lists of strings) corresponding to lines in the specified InputStream.
RecordIterator(java.io.Reader reader, int fields, boolean filter, java.lang.String delim) Returns an Iterator over records (lists of strings) corresponding to lines in the specified Reader.
RecordIterator(java.lang.String filename) Returns an Iterator over records (lists of strings) corresponding to lines in the specified file.
RecordIterator(java.lang.String filename, boolean filter) Returns an Iterator over records (lists of strings) corresponding to lines in the specified file.
RecordIterator(java.lang.String filename, int fields) Returns an Iterator over records (lists of strings) corresponding to lines in the specified file.
RecordIterator(java.lang.String filename, int fields, boolean filter) Returns an Iterator over records (lists of strings) corresponding to lines in the specified file.
RecordIterator(java.lang.String filename, int fields, boolean filter, java.lang.String delim) Returns an Iterator over records (lists of strings) corresponding to lines in the specified file.
RecordIterator(java.lang.String filename, java.lang.String delim) Returns an Iterator over records (lists of strings) corresponding to lines in the specified file.

Method Summary

Modifier and Type	Method and Description
static int	determineNumFields(java.lang.String filename) A static convenience method that tells you how many fields are in the first line of the specified file, using the default whitespace delimiter.
static int	determineNumFields(java.lang.String filename, java.lang.String delim) A static convenience method that tells you how many fields are in the first line of the specified file, using the specified regexp as delimiter.
static java.util.List<java.lang.String>	firstRecord(java.lang.String filename) A static convenience method that returns the first line of the specified file as list of strings, using the default whitespace delimiter.
static java.util.List<java.lang.String>	firstRecord(java.lang.String filename, java.lang.String delim) A static convenience method that returns the first line of the specified file as list of strings, using the specified regexp as delimiter.
boolean	hasNext()
static void	main(java.lang.String[] args) Just for testing.
java.util.List<java.lang.String>	next()
void	remove()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Detail

RecordIterator

public RecordIterator(java.io.Reader reader,
                      int fields,
                      boolean filter,
                      java.lang.String delim)

Returns an Iterator over records (lists of strings) corresponding to lines in the specified Reader.

Parameters:

reader - the reader to read from

fields - how many fields to expect in each record

filter - whether to filter lines containing wrong number of fields

delim - a regexp on which to split lines into fields (default whitespace)

RecordIterator

public RecordIterator(java.lang.String filename,
                      int fields,
                      boolean filter,
                      java.lang.String delim)
               throws java.io.FileNotFoundException

Returns an Iterator over records (lists of strings) corresponding to lines in the specified file.

Parameters:

filename - the file to read from

fields - how many fields to expect in each record

filter - whether to filter lines containing wrong number of fields

delim - a regexp on which to split lines into fields (default whitespace)

Throws:

java.io.FileNotFoundException

RecordIterator

public RecordIterator(java.io.InputStream in,
                      int fields,
                      boolean filter,
                      java.lang.String delim)

Returns an Iterator over records (lists of strings) corresponding to lines in the specified InputStream.

Parameters:

in - the InputStream to read from

fields - how many fields to expect in each record

filter - whether to filter lines containing wrong number of fields

delim - a regexp on which to split lines into fields (default whitespace)

RecordIterator

public RecordIterator(java.lang.String filename,
                      int fields,
                      boolean filter)
               throws java.io.FileNotFoundException

Returns an Iterator over records (lists of strings) corresponding to lines in the specified file. The default whitespace delimiter is used.

Parameters:

filename - the file to read from

fields - how many fields to expect in each record

filter - whether to filter lines containing wrong number of fields

Throws:

java.io.FileNotFoundException

RecordIterator

public RecordIterator(java.lang.String filename,
                      boolean filter)
               throws java.io.FileNotFoundException

Returns an Iterator over records (lists of strings) corresponding to lines in the specified file. The default whitespace delimiter is used. The first line is used to determine how many fields per record to expect.

Parameters:

filename - the file to read from

filter - whether to filter lines containing wrong number of fields

Throws:

java.io.FileNotFoundException

RecordIterator

public RecordIterator(java.lang.String filename,
                      int fields)
               throws java.io.FileNotFoundException

Returns an Iterator over records (lists of strings) corresponding to lines in the specified file. The default whitespace delimiter is used. Lines which contain other than fields fields are filtered.

Parameters:

filename - the file to read from

fields - how many fields to expect in each record

Throws:

java.io.FileNotFoundException

RecordIterator

public RecordIterator(java.lang.String filename,
                      java.lang.String delim)
               throws java.io.FileNotFoundException

Returns an Iterator over records (lists of strings) corresponding to lines in the specified file. No lines are filtered.

Parameters:

filename - the file to read from

delim - a regexp on which to split lines into fields (default whitespace)

Throws:

java.io.FileNotFoundException

RecordIterator

public RecordIterator(java.lang.String filename)
               throws java.io.FileNotFoundException

Returns an Iterator over records (lists of strings) corresponding to lines in the specified file. The default whitespace delimiter is used. No lines are filtered.

Parameters:

filename - the file to read from

Throws:

java.io.FileNotFoundException

RecordIterator

public RecordIterator(java.io.InputStream in)

Returns an Iterator over records (lists of strings) corresponding to lines in the specified InputStream. The default whitespace delimiter is used. No lines are filtered.

Parameters:

in - the stream to read from

Method Detail

hasNext

public boolean hasNext()

Specified by:

hasNext in interface java.util.Iterator<java.util.List<java.lang.String>>

next

public java.util.List<java.lang.String> next()

Specified by:

next in interface java.util.Iterator<java.util.List<java.lang.String>>

remove

public void remove()

Specified by:

remove in interface java.util.Iterator<java.util.List<java.lang.String>>

firstRecord

public static java.util.List<java.lang.String> firstRecord(java.lang.String filename,
                                                           java.lang.String delim)
                                                    throws java.io.FileNotFoundException

A static convenience method that returns the first line of the specified file as list of strings, using the specified regexp as delimiter.

Parameters:

filename - the file to read from

delim - a regexp on which to split lines into fields (default whitespace)

Throws:

java.io.FileNotFoundException

firstRecord

public static java.util.List<java.lang.String> firstRecord(java.lang.String filename)
                                                    throws java.io.FileNotFoundException

A static convenience method that returns the first line of the specified file as list of strings, using the default whitespace delimiter.

Parameters:

filename - the file to read from

Throws:

java.io.FileNotFoundException

determineNumFields

public static int determineNumFields(java.lang.String filename,
                                     java.lang.String delim)
                              throws java.io.FileNotFoundException

A static convenience method that tells you how many fields are in the first line of the specified file, using the specified regexp as delimiter.

Parameters:

filename - the file to read from

delim - a regexp on which to split lines into fields (default whitespace)

Throws:

java.io.FileNotFoundException

determineNumFields

public static int determineNumFields(java.lang.String filename)
                              throws java.io.FileNotFoundException

A static convenience method that tells you how many fields are in the first line of the specified file, using the default whitespace delimiter.

Parameters:

filename - the file to read from

Throws:

java.io.FileNotFoundException

main

public static void main(java.lang.String[] args)
                 throws java.io.FileNotFoundException

Just for testing. Reads from the file named on the command line, or from stdin, and echoes the records it reads to stdout.

Throws:

java.io.FileNotFoundException