org.apache.fulcrum.parser
Class DataStreamParser

java.lang.Object
  extended by org.apache.fulcrum.parser.DataStreamParser
All Implemented Interfaces:
Iterator, org.apache.avalon.framework.logger.LogEnabled
Direct Known Subclasses:
CSVParser, TSVParser

public abstract class DataStreamParser
extends Object
implements Iterator, org.apache.avalon.framework.logger.LogEnabled

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 732115 2009-01-06 20:54:04Z tv $
Author:
Sean Legassick

Field Summary
protected  org.apache.avalon.framework.logger.Logger log
          Logger to use
 
Constructor Summary
DataStreamParser(Reader in, List columnNames, String characterEncoding)
          Create a new DataStreamParser instance.
 
Method Summary
 void enableLogging(org.apache.avalon.framework.logger.Logger logger)
          Provide a logger
 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 abstract  void initTokenizer(StreamTokenizer tokenizer)
          Initialize the StreamTokenizer instance used to read the lines from the input reader.
 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(List columnNames)
          Set the list of column names explicitly.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

log

protected org.apache.avalon.framework.logger.Logger log
Logger to use

Constructor Detail

DataStreamParser

public DataStreamParser(Reader in,
                        List columnNames,
                        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 abstract void initTokenizer(StreamTokenizer tokenizer)
Initialize the StreamTokenizer instance used to read the lines from the input reader. This must be implemented in subclasses to set up the tokenizing properties.


enableLogging

public void enableLogging(org.apache.avalon.framework.logger.Logger logger)
Provide a logger

Specified by:
enableLogging in interface org.apache.avalon.framework.logger.LogEnabled
See Also:
LogEnabled.enableLogging(org.apache.avalon.framework.logger.Logger)

setColumnNames

public void setColumnNames(List columnNames)
Set the list of column names explicitly.

Parameters:
columnNames - A list of column names.

readColumnNames

public void readColumnNames()
                     throws IOException
Read the list of column names from the input reader using the tokenizer.

Throws:
IOException - an IOException occurred.

hasNextRow

public boolean hasNextRow()
                   throws IOException
Determine whether a further row of values exists in the input.

Returns:
true if the input has more rows.
Throws:
IOException - an IOException occurred.

nextRow

public ValueParser nextRow()
                    throws IOException,
                           NoSuchElementException
Returns a ValueParser object containing the next row of values.

Returns:
a ValueParser object.
Throws:
IOException - an IOException occurred.
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 Iterator
Returns:
true if the input has more rows.

next

public Object next()
            throws NoSuchElementException
Returns a ValueParser object containing the next row of values.

Specified by:
next in interface Iterator
Returns:
a ValueParser object as an Object.
Throws:
NoSuchElementException - there are no more rows in the input or an IOException occurred.

remove

public void remove()
            throws UnsupportedOperationException
The optional Iterator.remove method is not supported.

Specified by:
remove in interface Iterator
Throws:
UnsupportedOperationException - the operation is not supported.


Copyright © 2005-2009 The Apache Software Foundation. All Rights Reserved.