com.infomata.data
Class DataFile

java.lang.Object
  com.infomata.data.DataFile

public class DataFile

extends java.lang.Object

Main class for generating or reading data files written in widely accepted data format. Currently supported data formats are tab separate (TabFormat) and CSV (CSVFormat), but more data formats can easily be added by implementing DataFormat

USAGE:

 // Creating a reader for CSV file using ISO-8859-1
 
 DataFile read = DataFile.createReader("8859_1");
 read.setDataFormat(new CSVFormat());
 
 try
 {
 
     read.open(new File("/data/test.csv"));
 
     for (DataRow row = read.next(); row != null; row = read.next())
     {
         String text = row.getString(0);
         int number1 = row.getInt(1, 0);
         double number2 = row.getDouble(2);
         // use the retrieved data ...
     }
 }
 
 finally
 {
     read.close();
 }
 
 // Creating a writer for data file with European encoding
 // ISO-8859-2 (European) using tab separated format.
 // (rewrite existing file)
 
 DataFile write = DataFile.createWriter("8859_2", false);
 write.setDataFormat(new TabFormat());
 
 try
 {
 
     write.open(new File("/data/test.txt"));
 
     for (DataRow row = write.next(); row != null; row = write.next())
     {
         row.add("some German text");
         row.add(123);
         row.add(13323.23d);
     }
 }
 
 finally
 {
     write.close();
 }
 

Version:

$Revision: 1.3 $

Author:

Sam Kim

Method Summary

void	close() Closes a data file.
boolean	containsHeader() Checks if header indicator has been turned on using containsHeader(boolean).
void	containsHeader(boolean header) Sets the indicator for header row (must be first line of data file).
static DataFile	createReader(java.lang.String enc) Creates a reader instance of a data file.
static DataFile	createWriter(java.lang.String enc, boolean append) Creates a writer instance of DataFile used for writing a data file.
void	finalize() Finalization method that closes the file descriptor.
java.util.List	getHeaderList() Retrieves the list of header names found in the first row of the data file in the sequence they appear.
java.util.Iterator	getHeaderNames() Deprecated. use getHeaderList() instead.
DataRow	next() Retrieves the next row for reading or writing data
void	open(java.io.File file) Opens a data file for reading or writing
void	open(java.net.URL file)
void	setDataFormat(DataFormat format) Sets the data format to be read or written.

Methods inherited from class java.lang.Object

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

Method Detail

createReader

public static final DataFile createReader(java.lang.String enc)

Creates a reader instance of a data file.

Parameters:

enc - Java character encoding in which the data file is written.

Returns:

a reader instance of the DataFile.

createWriter

public static final DataFile createWriter(java.lang.String enc,
                                          boolean append)

Creates a writer instance of DataFile used for writing a data file.

Parameters:

enc - Java encoding to use while writing the data file containing none-English characters.

append - True if appending to existing data file. False, if writing to a new file or overwriting current file.

Returns:

a writer instance of DataFile.

containsHeader

public final void containsHeader(boolean header)

Sets the indicator for header row (must be first line of data file).

Parameters:

header - True if the file contains a header row. False, otherwise.

containsHeader

public final boolean containsHeader()

Checks if header indicator has been turned on using containsHeader(boolean). Data file reader lacks the logic to determine if the first row is a header row, automatically, so the existance of header row must be indicated prior to reading the data file.

Returns:

True, if header file indicator has been set to true. False, otherwise.

setDataFormat

public final void setDataFormat(DataFormat format)

Sets the data format to be read or written.

Parameters:

format - an instance of a class that implements DataFormat interface.

See Also:

DataFormat

finalize

public void finalize()

Finalization method that closes the file descriptor. This would work only if JVM is current (1.3 or later?).

close

public final void close()

Closes a data file.

open

public final void open(java.io.File file)
                throws java.io.IOException

Opens a data file for reading or writing

Parameters:

file - data file

Throws:

java.io.IOException - if an error occurs

open

public final void open(java.net.URL file)
                throws java.io.IOException

Throws:

java.io.IOException

next

public final DataRow next()
                   throws java.io.IOException

Retrieves the next row for reading or writing data

Returns:

a reference to next data row.

Throws:

java.io.IOException - if an error occurs

getHeaderNames

public final java.util.Iterator getHeaderNames()

Deprecated. use getHeaderList() instead.

Retrieves the list of header names found in the first row of the data file. In order for this to work, the header row indicator must be set prior to opening the data file. Note: the header names are not guaranteed to be the order they appear in the first row of the data file.

Returns:

header names (not guaranteed in the order in which they appear in file).

getHeaderList

public final java.util.List getHeaderList()

Retrieves the list of header names found in the first row of the data file in the sequence they appear. In order for this to work, the header row indicator must be set prior to opening the data file.

Returns:

header names (in sequence);