org.supercsv.cellprocessor.constraint

Class Unique

java.lang.Object

org.supercsv.cellprocessor.CellProcessorAdaptor

org.supercsv.cellprocessor.constraint.Unique

All Implemented Interfaces:

CellProcessor

public class Unique
extends CellProcessorAdaptor

Ensure that upon processing a CSV file (reading or writing), that values of the column all are unique. Comparison is based upon each elements equals() method of the objects and lookup takes O(1).

Compared to UniqueHashCode this processor potentially uses more memory, as it stores references to each encountered object rather than just their hashcodes. On reading huge files this can be a real memory-hazard, however, it ensures a true uniqueness check.

Since:

1.50

Author:

Kasper B. Graversen, Dominique De Vito, James Bassett

Field Summary

Fields inherited from class org.supercsv.cellprocessor.CellProcessorAdaptor

next

Constructor Summary

Constructors

Constructor and Description
Unique() Constructs a new Unique processor, which ensures that all rows in a column are unique.
Unique(CellProcessor next) Constructs a new Unique processor, which ensures that all rows in a column are unique, then calls the next processor in the chain.

Method Summary

Modifier and Type	Method and Description
Object	execute(Object value, CsvContext context) This method is invoked by the framework when the processor needs to process data or check constraints.

Methods inherited from class org.supercsv.cellprocessor.CellProcessorAdaptor

toString, validateInputNotNull

Methods inherited from class java.lang.Object

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

Constructor Detail

Unique

public Unique()

Constructs a new Unique processor, which ensures that all rows in a column are unique.

Unique

public Unique(CellProcessor next)

Constructs a new Unique processor, which ensures that all rows in a column are unique, then calls the next processor in the chain.

Parameters:

next - the next processor in the chain

Throws:

NullPointerException - if next is null

Method Detail

execute

public Object execute(Object value,
                      CsvContext context)

This method is invoked by the framework when the processor needs to process data or check constraints.

Parameters:

value - the value to be processed

context - the CSV context

Returns:

the result of cell processor execution

Throws:

SuperCsvCellProcessorException - if value is null

SuperCsvConstraintViolationException - if a non-unique value is encountered