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.
- Version:
- $Id: ColumnRenamer.java,v 1.2 2006/09/15 17:53:37 cyganiak Exp $
- Author:
- Richard Cyganiak (richard@cyganiak.de)
Field Summary |
static ColumnRenamer |
NULL
An optimized ColumnRenamer that leaves every column unchanged |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
NULL
public static final ColumnRenamer NULL
- An optimized ColumnRenamer that leaves every column unchanged
ColumnRenamer
public ColumnRenamer()
invertMap
protected static final Map invertMap(Map 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
applyToColumnSet
public Set applyToColumnSet(Set columns)
applyToColumnList
public List applyToColumnList(List columns)
applyToJoinSet
public Set applyToJoinSet(Set joins)
applyTo
public ResultRow applyTo(ResultRow row)
applyToMapKeys
public abstract Map applyToMapKeys(Map mapWithColumnKeys)
applyTo
public abstract AliasMap applyTo(AliasMap aliases)