Class ColumnPositionMappingStrategy<T>

java.lang.Object

com.opencsv.bean.AbstractMappingStrategy<String, Integer, ComplexFieldMapEntry<String,Integer,T>, T>

com.opencsv.bean.ColumnPositionMappingStrategy<T>

Type Parameters:

T - Type of object that is being processed.

All Implemented Interfaces:

MappingStrategy<T>

public class ColumnPositionMappingStrategy<T>
extends AbstractMappingStrategy<String, Integer, ComplexFieldMapEntry<String,Integer,T>, T>

Allows for the mapping of columns with their positions. Using this strategy without annotations (CsvBindByPosition or CsvCustomBindByPosition) requires all the columns to be present in the CSV file and for them to be in a particular order. Using annotations allows one to specify arbitrary zero-based column numbers for each bean member variable to be filled. Also this strategy requires that the file does NOT have a header. That said, the main use of this strategy is files that do not have headers.

Nested Class Summary

Nested classes/interfaces inherited from class AbstractMappingStrategy

AbstractMappingStrategy.RecursiveType

Field Summary

Fields

Modifier and Type	Field	Description
private Integer[]	columnIndexForWriting	Used to store a mapping from presumed input column index to desired output column index, as determined by applying writeOrder.
private boolean	columnsExplicitlySet	Whether the user has programmatically set the map from column positions to field names.
private FieldMapByPosition<T>	fieldMap	The map from column position to BeanField.
private Comparator<Integer>	writeOrder	Holds a Comparator to sort columns on writing.

Fields inherited from class AbstractMappingStrategy

errorLocale, headerIndex, profile, recursiveTypeTree, type

Constructor Summary

Constructors

Constructor	Description
ColumnPositionMappingStrategy()	Default constructor.

Method Summary

Modifier and Type	Method	Description
void	captureHeader(CSVReader reader)	There is no header per se for this mapping strategy, but this method checks the first line to determine how many fields are present and adjusts its field map accordingly.
protected Integer	chooseMultivaluedFieldIndexFromHeaderIndex(int index)	For BeanField.indexAndSplitMultivaluedField(java.lang.Object, java.lang.Object) it is necessary to determine which index to pass in.
protected BeanField<T,Integer>	findField(int col)	Gets the field for a given column position.
String	findHeader(int col)	Returns the column position for the given column number.
String[]	generateHeader(T bean)	This method returns an empty array.
protected Set<Class<? extends Annotation>>	getBindingAnnotations()	Returns a set of the annotations that are used for binding in this mapping strategy.
String[]	getColumnMapping()	Retrieves the column mappings.
String	getColumnName(int col)	Gets a column name.
protected FieldMap<String, Integer, ? extends ComplexFieldMapEntry<String,Integer,T>, T>	getFieldMap()	Returns the FieldMap associated with this mapping strategy.
protected void	initializeFieldMap()	Creates an empty binding-type-specific field map that can be filled in later steps.
protected void	loadAnnotatedFieldMap(org.apache.commons.collections4.ListValuedMap<Class<?>,Field> fields)	Creates a map of annotated fields in the bean to be processed.
protected void	loadUnadornedFieldMap(org.apache.commons.collections4.ListValuedMap<Class<?>,Field> fields)	Creates a map of fields in the bean to be processed that have no annotations.
private void	registerBinding(CsvBindByPosition annotation, Class<?> localType, Field localField)	Register a binding between a bean field and a simple converter.
private void	registerCustomBinding(CsvCustomBindByPosition annotation, Class<?> localType, Field localField)	Register a binding between a bean field and a custom converter.
private void	registerJoinBinding(CsvBindAndJoinByPosition annotation, Class<?> localType, Field localField)	Register a binding between a bean field and a multi-valued converter that joins values from multiple columns.
private void	registerSplitBinding(CsvBindAndSplitByPosition annotation, Class<?> localType, Field localField)	Register a binding between a bean field and a collection converter that splits input into multiple values.
void	setColumnMapping(String... columnMapping)	Setter for the column mapping.
void	setColumnOrderOnWrite(Comparator<Integer> writeOrder)	Sets the Comparator to be used to sort columns when writing beans to a CSV file.
protected void	verifyLineLength(int numberOfFields)	Must be called once the length of input for a line/record is known to verify that the line was complete.

Methods inherited from class AbstractMappingStrategy

createBean, determineConverter, filterIgnoredFields, getType, ignoreFields, indexBean, instantiateCustomConverter, isForbiddenClassForRecursion, loadFieldMap, loadRecursiveClasses, partitionFields, populateNewBean, selectAnnotationForProfile, setErrorLocale, setFieldValue, setProfile, setType, transmuteBean

Methods inherited from class Object

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

Methods inherited from interface MappingStrategy

isAnnotationDriven

Field Details

columnsExplicitlySet

private boolean columnsExplicitlySet

Whether the user has programmatically set the map from column positions to field names.

fieldMap

private FieldMapByPosition<T> fieldMap

The map from column position to BeanField.

writeOrder

private Comparator<Integer> writeOrder

Holds a Comparator to sort columns on writing.

columnIndexForWriting

private Integer[] columnIndexForWriting

Used to store a mapping from presumed input column index to desired output column index, as determined by applying writeOrder.

Constructor Details

ColumnPositionMappingStrategy

public ColumnPositionMappingStrategy()

Default constructor. Considered stable.

See Also:

• ColumnPositionMappingStrategyBuilder

Method Details

captureHeader

public void captureHeader(CSVReader reader)
                   throws IOException

There is no header per se for this mapping strategy, but this method checks the first line to determine how many fields are present and adjusts its field map accordingly.

Parameters:

reader - The CSVReader to use for header parsing

Throws:

IOException - If parsing fails

chooseMultivaluedFieldIndexFromHeaderIndex

protected Integer chooseMultivaluedFieldIndexFromHeaderIndex(int index)

Description copied from class: AbstractMappingStrategy

For BeanField.indexAndSplitMultivaluedField(java.lang.Object, java.lang.Object) it is necessary to determine which index to pass in.

Specified by:

chooseMultivaluedFieldIndexFromHeaderIndex in class AbstractMappingStrategy<String, Integer, ComplexFieldMapEntry<String,Integer,T>, T>

Parameters:

index - The current column position while transmuting a bean to CSV output

Returns:

The index to be used for this mapping strategy for BeanField.indexAndSplitMultivaluedField(java.lang.Object, java.lang.Object) For this mapping strategy, it's simply index wrapped as an Integer.

findField

protected BeanField<T,Integer> findField(int col)

Description copied from class: AbstractMappingStrategy

Gets the field for a given column position.

Specified by:

findField in class AbstractMappingStrategy<String, Integer, ComplexFieldMapEntry<String,Integer,T>, T>

Parameters:

col - The column to find the field for

Returns:

BeanField containing the field for a given column position, or null if one could not be found

generateHeader

public String[] generateHeader(T bean)
                        throws CsvRequiredFieldEmptyException

This method returns an empty array. The column position mapping strategy assumes that there is no header, and thus it also does not write one, accordingly.

Specified by:

generateHeader in interface MappingStrategy<T>

Overrides:

generateHeader in class AbstractMappingStrategy<String, Integer, ComplexFieldMapEntry<String,Integer,T>, T>

Parameters:

bean - One fully populated bean from which the header can be derived. This is important in the face of joining and splitting. If we have a MultiValuedMap as a field that is the target for a join on reading, that same field must be split into multiple columns on writing. Since the joining is done via regular expressions, it is impossible for opencsv to know what the column names are supposed to be on writing unless this bean includes a fully populated map.

Returns:

An empty array

Throws:

CsvRequiredFieldEmptyException - If a required header is missing while attempting to write. Since every other header is hard-wired through the bean fields and their associated annotations, this can only happen with multi-valued fields.

getColumnName

public String getColumnName(int col)

Gets a column name.

Overrides:

getColumnName in class AbstractMappingStrategy<String, Integer, ComplexFieldMapEntry<String,Integer,T>, T>

Parameters:

col - Position of the column.

Returns:

Column name or null if col > number of mappings.

getColumnMapping

public String[] getColumnMapping()

Retrieves the column mappings.

Returns:

String array with the column mappings.

setColumnMapping

public void setColumnMapping(String... columnMapping)

Setter for the column mapping. This mapping is for reading. Use of this method in conjunction with writing is undefined.

Parameters:

columnMapping - Column names to be mapped.

registerCustomBinding

private void registerCustomBinding(CsvCustomBindByPosition annotation,
 Class<?> localType,
 Field localField)

Register a binding between a bean field and a custom converter.

Parameters:

annotation - The annotation attached to the bean field

localType - The class/type in which the field resides

localField - The bean field

registerSplitBinding

private void registerSplitBinding(CsvBindAndSplitByPosition annotation,
 Class<?> localType,
 Field localField)

Register a binding between a bean field and a collection converter that splits input into multiple values.

Parameters:

annotation - The annotation attached to the bean field

localType - The class/type in which the field resides

localField - The bean field

registerJoinBinding

private void registerJoinBinding(CsvBindAndJoinByPosition annotation,
 Class<?> localType,
 Field localField)

Register a binding between a bean field and a multi-valued converter that joins values from multiple columns.

Parameters:

annotation - The annotation attached to the bean field

localType - The class/type in which the field resides

localField - The bean field

registerBinding

private void registerBinding(CsvBindByPosition annotation,
 Class<?> localType,
 Field localField)

Register a binding between a bean field and a simple converter.

Parameters:

annotation - The annotation attached to the bean field

localType - The class/type in which the field resides

localField - The bean field

loadAnnotatedFieldMap

protected void loadAnnotatedFieldMap(org.apache.commons.collections4.ListValuedMap<Class<?>,Field> fields)

Creates a map of annotated fields in the bean to be processed.

This method is called by AbstractMappingStrategy.loadFieldMap() when at least one relevant annotation is found on a member variable.

Overrides:

loadAnnotatedFieldMap in class AbstractMappingStrategy<String, Integer, ComplexFieldMapEntry<String,Integer,T>, T>

Parameters:

fields - A list of fields annotated with a binding annotation in the bean to be processed

loadUnadornedFieldMap

protected void loadUnadornedFieldMap(org.apache.commons.collections4.ListValuedMap<Class<?>,Field> fields)

Description copied from class: AbstractMappingStrategy

Creates a map of fields in the bean to be processed that have no annotations. This method is called by AbstractMappingStrategy.loadFieldMap() when absolutely no annotations that are relevant for this mapping strategy are found in the type of bean being processed.

Specified by:

loadUnadornedFieldMap in class AbstractMappingStrategy<String, Integer, ComplexFieldMapEntry<String,Integer,T>, T>

Parameters:

fields - A list of all non-synthetic fields in the bean to be processed

getBindingAnnotations

protected Set<Class<? extends Annotation>> getBindingAnnotations()

Returns a set of the annotations that are used for binding in this mapping strategy.

In this mapping strategy, those are currently:

• CsvBindByPosition
• CsvCustomBindByPosition
• CsvBindAndJoinByPosition
• CsvBindAndSplitByPosition

Overrides:

getBindingAnnotations in class AbstractMappingStrategy<String, Integer, ComplexFieldMapEntry<String,Integer,T>, T>

Returns:

Annotations of the sort CsvBindByName or CsvBindByPosition that are relevant for binding input fields to bean members in this mapping strategy

initializeFieldMap

protected void initializeFieldMap()

Description copied from class: AbstractMappingStrategy

Creates an empty binding-type-specific field map that can be filled in later steps.

This method may be called multiple times and must erase any state information from previous calls.

Specified by:

initializeFieldMap in class AbstractMappingStrategy<String, Integer, ComplexFieldMapEntry<String,Integer,T>, T>

verifyLineLength

protected void verifyLineLength(int numberOfFields)
                         throws CsvRequiredFieldEmptyException

Description copied from class: AbstractMappingStrategy

Must be called once the length of input for a line/record is known to verify that the line was complete. Complete in this context means, no required fields are missing. The issue here is, as long as a column is present but empty, we can check whether the field is required and throw an exception if it is not, but if the data end prematurely, we never have this chance without indication that no more data are on the way. Another validation is that the number of fields must match the number of headers to prevent a data mismatch situation.

Specified by:

verifyLineLength in class AbstractMappingStrategy<String, Integer, ComplexFieldMapEntry<String,Integer,T>, T>

Parameters:

numberOfFields - The number of fields present in the line of input

Throws:

CsvRequiredFieldEmptyException - If a required column is missing

findHeader

public String findHeader(int col)

Returns the column position for the given column number. Yes, they're the same thing. For this mapping strategy, it's a simple conversion from an integer to a string.

Specified by:

findHeader in class AbstractMappingStrategy<String, Integer, ComplexFieldMapEntry<String,Integer,T>, T>

Parameters:

col - The column number for which the header is sought

Returns:

The name of the header

getFieldMap

protected FieldMap<String, Integer, ? extends ComplexFieldMapEntry<String,Integer,T>, T> getFieldMap()

Description copied from class: AbstractMappingStrategy

Returns the FieldMap associated with this mapping strategy.

Specified by:

getFieldMap in class AbstractMappingStrategy<String, Integer, ComplexFieldMapEntry<String,Integer,T>, T>

Returns:

The FieldMap used by this strategy

setColumnOrderOnWrite

public void setColumnOrderOnWrite(Comparator<Integer> writeOrder)

Sets the Comparator to be used to sort columns when writing beans to a CSV file. Behavior of this method when used on a mapping strategy intended for reading data from a CSV source is not defined.

Parameters:

writeOrder - The Comparator to use. May be null, in which case the natural ordering is used.

Since:

4.3