org.apache.turbine.util.parser
Class DataStreamParser

java.lang.Object
  org.apache.turbine.util.parser.DataStreamParser

All Implemented Interfaces:

java.util.Iterator

Direct Known Subclasses:

CSVParser, DataStreamParser, TSVParser

public abstract class DataStreamParser

extends java.lang.Object

implements java.util.Iterator

DataStreamParser is used to parse a stream with a fixed format and generate ValueParser objects which can be used to extract the values in the desired type.

The class itself is abstract - a concrete subclass which implements the initTokenizer method such as CSVParser or TSVParser is required to use the functionality.

The class implements the java.util.Iterator interface for convenience. This allows simple use in a Velocity template for example:

 #foreach ($row in $datastream)
   Name: $row.Name
   Description: $row.Description
 #end
 

Version:

$Id: DataStreamParser.java 280284 2005-09-12 07:57:42Z henning $

Author:

Sean Legassick, Martin van den Bemt, Henning P. Schmiedehausen

Field Summary

protected static java.lang.String

EMPTYFIELDNAME The constant for empty fields

Constructor Summary

DataStreamParser(java.io.Reader in, java.util.List columnNames, java.lang.String characterEncoding)
Create a new DataStreamParser instance.

Method Summary

java.util.List	getColumnNames() get the list of column names.
boolean	hasNext() Determine whether a further row of values exists in the input.
boolean	hasNextRow() Determine whether a further row of values exists in the input.
protected void	initTokenizer(java.io.StreamTokenizer tokenizer) Initialize the StreamTokenizer instance used to read the lines from the input reader.
java.lang.Object	next() Returns a ValueParser object containing the next row of values.
ValueParser	nextRow() Returns a ValueParser object containing the next row of values.
void	readColumnNames() Read the list of column names from the input reader using the tokenizer.
void	remove() The optional Iterator.remove method is not supported.
void	setColumnNames(java.util.List columnNames) Set the list of column names explicitly.
void	setFieldSeparator(char fieldSeparator) This method must be called to setup the field seperator

Methods inherited from class java.lang.Object

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

Field Detail

EMPTYFIELDNAME

protected static final java.lang.String EMPTYFIELDNAME

The constant for empty fields

See Also:

Constant Field Values

Constructor Detail

DataStreamParser

public DataStreamParser(java.io.Reader in,
                        java.util.List columnNames,
                        java.lang.String characterEncoding)

Create a new DataStreamParser instance. Requires a Reader to read the comma-separated values from, a list of column names and a character encoding.

Parameters:

in - the input reader.

columnNames - a list of column names.

characterEncoding - the character encoding of the input.

Method Detail

initTokenizer

protected void initTokenizer(java.io.StreamTokenizer tokenizer)

Initialize the StreamTokenizer instance used to read the lines from the input reader. This must be implemented in subclasses to set up other tokenizing properties.

Parameters:

tokenizer - the tokenizer to adjust

setFieldSeparator

public void setFieldSeparator(char fieldSeparator)

This method must be called to setup the field seperator

Parameters:

fieldSeparator - the char which separates the fields

setColumnNames

public void setColumnNames(java.util.List columnNames)

Set the list of column names explicitly.

Parameters:

columnNames - A list of column names.

getColumnNames

public java.util.List getColumnNames()

get the list of column names.

readColumnNames

public void readColumnNames()
                     throws java.io.IOException

Read the list of column names from the input reader using the tokenizer. If fieldNames are empty, we use the current fieldNumber + the EMPTYFIELDNAME to make one up.

Throws:

java.io.IOException - an IOException occurred.

hasNextRow

public boolean hasNextRow()
                   throws java.io.IOException

Determine whether a further row of values exists in the input.

Returns:

true if the input has more rows.

Throws:

java.io.IOException - an IOException occurred.

nextRow

public ValueParser nextRow()
                    throws java.io.IOException,
                           java.util.NoSuchElementException

Returns a ValueParser object containing the next row of values.

Returns:

a ValueParser object.

Throws:

java.io.IOException - an IOException occurred.

java.util.NoSuchElementException - there are no more rows in the input.

hasNext

public boolean hasNext()

Determine whether a further row of values exists in the input.

Specified by:

hasNext in interface java.util.Iterator

Returns:

true if the input has more rows.

next

public java.lang.Object next()
                      throws java.util.NoSuchElementException

Returns a ValueParser object containing the next row of values.

Specified by:

next in interface java.util.Iterator

Returns:

a ValueParser object as an Object.

Throws:

java.util.NoSuchElementException - there are no more rows in the input or an IOException occurred.

remove

public void remove()
            throws java.lang.UnsupportedOperationException

The optional Iterator.remove method is not supported.

Specified by:

remove in interface java.util.Iterator

Throws:

java.lang.UnsupportedOperationException - the operation is not supported.