PlacementPlan (Solr 9.9.0 core API)

```
public interface PlacementPlan
```
A fully specified plan or instructions for placement, deletion or move to be applied to the cluster.
Fully specified means the actual Node's on which to place replicas have been decided.
Instances are created by plugin code using PlacementPlanFactory. This interface obviously doesn't expose much but the underlying Solr side implementation has all that is needed (and will do at least one cast in order to execute the plan, likely then using some type of visitor pattern).

- Method Summary
  
  All Methods Instance Methods Abstract Methods
  Modifier and Type Method Description
  
  Set<ReplicaPlacement> getReplicaPlacements()
  
  PlacementRequest getRequest()

- Method Detail
  - getRequest
```
PlacementRequest getRequest()
```
    Returns:
    
    the PlacementRequest at the origin of this PlacementPlan, as passed to the PlacementPlanFactory method that created this instance.
  - getReplicaPlacements
```
Set<ReplicaPlacement> getReplicaPlacements()
```
    Returns:
    
    the set of ReplicaPlacement's computed by the plugin to implement the request