UnionFlattenerImpl (ontop-optimization 4.3.0-SNAPSHOT API)

java.lang.Object
- it.unibz.inf.ontop.datalog.impl.UnionFlattenerImpl

All Implemented Interfaces:

UnionFlattener, IQOptimizer
```
public class UnionFlattenerImpl
extends Object
implements UnionFlattener
```
Lifts unions above projections, until a fixed point is reached. Also merges consecutive unions and projections.
This normalization may be needed for datalog-based mapping optimizers.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`IQ`	`optimize(IQ query)`	TODO: why a fix point?
`IQTree`	`optimize(IQTree tree, VariableGenerator variableGenerator)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - optimize
```
public IQ optimize(IQ query)
```
    TODO: why a fix point?
    
    Specified by:
    
    optimize in interface IQOptimizer
    
    Specified by:
    
    optimize in interface UnionFlattener
  - optimize
```
public IQTree optimize(IQTree tree,
                       VariableGenerator variableGenerator)
```
    Specified by:
    
    optimize in interface UnionFlattener