de.fuberlin.wiwiss.d2rq.algebra

Class ColumnRenamer

java.lang.Object

de.fuberlin.wiwiss.d2rq.algebra.ColumnRenamer

Direct Known Subclasses:

AliasMap, ColumnRenamerMap

public abstract class ColumnRenamer
extends Object

Something that can rename columns in various objects.

Author:

Richard Cyganiak (richard@cyganiak.de)

Field Summary

Fields

Modifier and Type	Field and Description
static ColumnRenamer	NULL An optimized ColumnRenamer that leaves every column unchanged

Constructor Summary

Constructors

Constructor and Description
ColumnRenamer()

Method Summary

Methods

Modifier and Type	Method and Description
abstract AliasMap	applyTo(AliasMap aliases)
abstract Attribute	applyTo(Attribute original)
Expression	applyTo(Expression original)
Join	applyTo(Join original)
List<OrderSpec>	applyTo(List<OrderSpec> orderSpecs)
ProjectionSpec	applyTo(ProjectionSpec original)
Set<Join>	applyToJoinSet(Set<Join> joins)
Set<ProjectionSpec>	applyToProjectionSet(Set<ProjectionSpec> projections)
protected static <K,V> Map<V,K>	invertMap(Map<K,V> m) Returns a new map with keys and values exchanged.

Methods inherited from class java.lang.Object

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

Field Detail

NULL

public static final ColumnRenamer NULL

An optimized ColumnRenamer that leaves every column unchanged

Constructor Detail

ColumnRenamer

public ColumnRenamer()

Method Detail

invertMap

protected static final <K,V> Map<V,K> invertMap(Map<K,V> m)

Returns a new map with keys and values exchanged. Lossy if multiple keys in the original have equal values.

Parameters:

m - The original map

Returns:

An inverse map

applyTo

public abstract Attribute applyTo(Attribute original)

Parameters:

original - A column

Returns:

The renamed version of that column, or the same column if the renamer does not apply to this argument

applyTo

public Join applyTo(Join original)

Parameters:

original - A join

Returns:

A join with all columns renamed according to this Renamer

applyTo

public Expression applyTo(Expression original)

Parameters:

original - An expression

Returns:

An expression with all columns renamed according to this Renamer

applyToJoinSet

public Set<Join> applyToJoinSet(Set<Join> joins)

applyTo

public ProjectionSpec applyTo(ProjectionSpec original)

applyToProjectionSet

public Set<ProjectionSpec> applyToProjectionSet(Set<ProjectionSpec> projections)

applyTo

public List<OrderSpec> applyTo(List<OrderSpec> orderSpecs)

applyTo

public abstract AliasMap applyTo(AliasMap aliases)