Package org.openrefine.wikibase.schema

Class WbVariableExpr<T>

java.lang.Object

org.openrefine.wikibase.schema.WbVariableExpr<T>

Type Parameters:

T - the type of Wikibase value returned by the expression.

All Implemented Interfaces:

WbExpression<T>

Direct Known Subclasses:

WbDateVariable, WbEntityVariable, WbItemVariable, WbLanguageVariable, WbLocationVariable, WbStringVariable

public abstract class WbVariableExpr<T>
extends Object
implements WbExpression<T>

A base class for expressions which draw their values from a particular column.

Author:

Antonin Delpeuch

Field Summary

Fields

Modifier and Type	Field	Description
static String	NO_VALUE_KEYWORD
static String	SOME_VALUE_KEYWORD

Constructor Summary

Constructors

Constructor	Description
WbVariableExpr()	Constructs a variable without setting the column name yet.

Method Summary

Modifier and Type	Method	Description
protected boolean	equalAsVariables(Object other, Class<? extends WbVariableExpr<?>> targetClass)	Helper for equality methods of subclasses.
T	evaluate(ExpressionContext ctxt)	Evaluates the expression in a given context, returning
abstract T	fromCell(Cell cell, ExpressionContext ctxt)	Method that should be implemented by subclasses, converting an OpenRefine cell to a Wikibase value.
String	getColumnName()	Returns the column name used by the variable.
int	hashCode()
void	setColumnName(String columnName)	Changes the column name used by the variable.
void	validate(ValidationState validation)	Checks that we have a valid column name.

Methods inherited from class java.lang.Object

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

Field Detail

NO_VALUE_KEYWORD

public static final String NO_VALUE_KEYWORD

See Also:

Constant Field Values

SOME_VALUE_KEYWORD

public static final String SOME_VALUE_KEYWORD

See Also:

Constant Field Values

Constructor Detail

WbVariableExpr

public WbVariableExpr()

Constructs a variable without setting the column name yet.

Method Detail

validate

public void validate(ValidationState validation)

Checks that we have a valid column name.

Specified by:

validate in interface WbExpression<T>

Parameters:

validation - the state in which to log any validation errors

getColumnName

public String getColumnName()

Returns the column name used by the variable.

Returns:

the OpenRefine column name

setColumnName

public void setColumnName(String columnName)

Changes the column name used by the variable. This is useful for deserialization, as well as updates when column names change.

evaluate

public T evaluate(ExpressionContext ctxt)
           throws SkipSchemaExpressionException,
                  QAWarningException,
                  SpecialValueNoValueException,
                  SpecialValueSomeValueException

Evaluates the expression in a given context, returning

Specified by:

evaluate in interface WbExpression<T>

Throws:

QAWarningException

SpecialValueNoValueException

SpecialValueSomeValueException

SkipSchemaExpressionException

fromCell

public abstract T fromCell(Cell cell,
                           ExpressionContext ctxt)
                    throws SkipSchemaExpressionException,
                           QAWarningException

Method that should be implemented by subclasses, converting an OpenRefine cell to a Wikibase value. Access to other values and emitting warnings is possible via the supplied EvaluationContext object.

Parameters:

cell - the cell to convert

ctxt - the evaluation context

Returns:

the corresponding Wikibase value

Throws:

SkipSchemaExpressionException

QAWarningException

equalAsVariables

protected boolean equalAsVariables(Object other,
                                   Class<? extends WbVariableExpr<?>> targetClass)

Helper for equality methods of subclasses.

Parameters:

other - the object to compare

targetClass - the target class for equality

Returns:

hashCode

public int hashCode()

Overrides:

hashCode in class Object