Impacts (Lucene 9.4.2 core API)

java.lang.Object
- org.apache.lucene.index.Impacts

```
public abstract class Impacts
extends Object
```
Information about upcoming impacts, ie. (freq, norm) pairs.

Constructor Summary

Constructors
Modifier Constructor Description

protected Impacts()
Sole constructor.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`abstract int`	`getDocIdUpTo(int level)`	Return the maximum inclusive doc ID until which the list of impacts returned by `getImpacts(int)` is valid.
`abstract List<Impact>`	`getImpacts(int level)`	Return impacts on the given level.
`abstract int`	`numLevels()`	Return the number of levels on which we have impacts.

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

- Constructor Detail
  - Impacts
```
protected Impacts()
```
    Sole constructor. Typically invoked by sub classes.
- Method Detail
  - numLevels
```
public abstract int numLevels()
```
    Return the number of levels on which we have impacts. The returned value is always greater than 0 and may not always be the same, even on a single postings list, depending on the current doc ID.
  - getDocIdUpTo
```
public abstract int getDocIdUpTo(int level)
```
    Return the maximum inclusive doc ID until which the list of impacts returned by getImpacts(int) is valid. This is a non-decreasing function of level.
  - getImpacts
```
public abstract List<Impact> getImpacts(int level)
```
    Return impacts on the given level. These impacts are sorted by increasing frequency and increasing unsigned norm, and only valid until the doc ID returned by getDocIdUpTo(int) for the same level, included. The returned list is never empty. NOTE: There is no guarantee that these impacts actually appear in postings, only that they trigger scores that are greater than or equal to the impacts that actually appear in postings.