org.apache.lucene.codecs

## Class NormsFormat

- java.lang.Object
- - org.apache.lucene.codecs.NormsFormat

Direct Known Subclasses:
  Lucene40NormsFormat, Lucene42NormsFormat

    public abstract class NormsFormat
    extends Object

Encodes/decodes per-document score normalization values.

### Constructor Summary

Constructors
`protected` `NormsFormat()` Sole constructor.

### Method Summary

Methods
`abstract DocValuesConsumer` `normsConsumer(SegmentWriteState state)` Returns a `DocValuesConsumer` to write norms to the index.
`abstract DocValuesProducer` `normsProducer(SegmentReadState state)` Returns a `DocValuesProducer` to read norms from the index.

### Methods inherited from class java.lang.Object

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

### Constructor Detail

#### NormsFormat

    protected NormsFormat()

Sole constructor. (For invocation by subclass constructors, typically implicit.)

### Method Detail

#### normsConsumer

    public abstract DocValuesConsumer normsConsumer(SegmentWriteState state)
                                             throws IOException

Returns a `DocValuesConsumer` to write norms to the index.

Throws:
  `IOException`

#### normsProducer

    public abstract DocValuesProducer normsProducer(SegmentReadState state)
                                             throws IOException

Returns a `DocValuesProducer` to read norms from the index.

NOTE: by the time this call returns, it must hold open any files it will need to use; else, those files may be deleted. Additionally, required files may be deleted during the execution of this call before there is a chance to open them. Under these circumstances an IOException should be thrown by the implementation. IOExceptions are expected and will automatically cause a retry of the segment opening logic with the newly revised segments.

Throws:
  `IOException`