de.fuberlin.wiwiss.d2rq.values

Class SQLExpressionValueMaker

java.lang.Object

de.fuberlin.wiwiss.d2rq.values.SQLExpressionValueMaker

All Implemented Interfaces:

ValueMaker

public class SQLExpressionValueMaker
extends Object
implements ValueMaker

A value maker that creates its values from a SQL expression. TODO Write unit tests

Author:

Richard Cyganiak (richard@cyganiak.de)

Field Summary

Fields inherited from interface de.fuberlin.wiwiss.d2rq.values.ValueMaker

NULL

Constructor Summary

Constructors

Constructor and Description
SQLExpressionValueMaker(Expression expression)

Method Summary

Methods

Modifier and Type	Method and Description
void	describeSelf(NodeSetFilter c)
boolean	equals(Object other)
int	hashCode()
String	makeValue(ResultRow row) Retrieves a value from a database row according to some rule or pattern.
List<OrderSpec>	orderSpecs(boolean ascending)
Set<ProjectionSpec>	projectionSpecs() Returns a set of all ProjectionSpecs containing data necessary for this ValueSource.
ValueMaker	renameAttributes(ColumnRenamer renamer)
String	toString()
Expression	valueExpression(String value) A SQL expression that selects only rows where this value maker produces the specified value.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

SQLExpressionValueMaker

public SQLExpressionValueMaker(Expression expression)

Method Detail

describeSelf

public void describeSelf(NodeSetFilter c)

Specified by:

describeSelf in interface ValueMaker

projectionSpecs

public Set<ProjectionSpec> projectionSpecs()

Description copied from interface: ValueMaker

Returns a set of all ProjectionSpecs containing data necessary for this ValueSource.

Specified by:

projectionSpecs in interface ValueMaker

Returns:

a set of ProjectionSpecs

makeValue

public String makeValue(ResultRow row)

Description copied from interface: ValueMaker

Retrieves a value from a database row according to some rule or pattern.

Specified by:

makeValue in interface ValueMaker

Parameters:

row - the database row

Returns:

a value created from the row

valueExpression

public Expression valueExpression(String value)

Description copied from interface: ValueMaker

A SQL expression that selects only rows where this value maker produces the specified value. Expression.FALSE if this value maker is incapable of producing the value.

Specified by:

valueExpression in interface ValueMaker

Parameters:

value - A value

Returns:

An expression that selects rows that produce this value

renameAttributes

public ValueMaker renameAttributes(ColumnRenamer renamer)

Specified by:

renameAttributes in interface ValueMaker

orderSpecs

public List<OrderSpec> orderSpecs(boolean ascending)

Specified by:

orderSpecs in interface ValueMaker

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object other)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object