Package org.apache.lucene.codecs

# Class NormsConsumer

java.lang.Object
org.apache.lucene.codecs.NormsConsumer

All Implemented Interfaces:
  `Closeable`, `AutoCloseable`

public abstract class NormsConsumer extends Object implements Closeable
Abstract API that consumes normalization values. Concrete implementations of this actually do "something" with the norms (write it into the index in a specific format).

The lifecycle is:

1. NormsConsumer is created by `NormsFormat.normsConsumer(SegmentWriteState)`.
2. `addNormsField(org.apache.lucene.index.FieldInfo, org.apache.lucene.codecs.NormsProducer)` is called for each field with normalization values. The API is a "pull" rather than "push", and the implementation is free to iterate over the values multiple times (`Iterable.iterator()`).
3. After all fields are added, the consumer is `Closeable.close()`d.

WARNING: This API is experimental and might change in incompatible ways in the next release.

- ## Constructor Summary

  Constructors
  Modifier
  Constructor
  Description
  `protected`
  `NormsConsumer()`
  Sole constructor.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `abstract void`
  `addNormsField(FieldInfo field, NormsProducer normsProducer)`
  Writes normalization values for a field.
  `void`
  `merge(MergeState mergeState)`
  Merges in the fields from the readers in `mergeState`.
  `void`
  `mergeNormsField(FieldInfo mergeFieldInfo, MergeState mergeState)`
  Merges the norms from `toMerge`.

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

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

  ### Methods inherited from interface java.io.Closeable

  `close`

- ## Constructor Details

  - ### NormsConsumer

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

- ## Method Details

  - ### addNormsField

    public abstract void addNormsField(FieldInfo field, NormsProducer normsProducer) throws IOException
    Writes normalization values for a field.
    Parameters:
      `field` - field information
      `normsProducer` - NormsProducer of the numeric norm values
    Throws:
      `IOException` - if an I/O error occurred.

  - ### merge

    public void merge(MergeState mergeState) throws IOException
    Merges in the fields from the readers in `mergeState`. The default implementation calls `mergeNormsField(org.apache.lucene.index.FieldInfo, org.apache.lucene.index.MergeState)` for each field, filling segments with missing norms for the field with zeros. Implementations can override this method for more sophisticated merging (bulk-byte copying, etc).
    Throws:
      `IOException`

  - ### mergeNormsField

    public void mergeNormsField(FieldInfo mergeFieldInfo, MergeState mergeState) throws IOException
    Merges the norms from `toMerge`.

    The default implementation calls `addNormsField(org.apache.lucene.index.FieldInfo, org.apache.lucene.codecs.NormsProducer)`, passing an Iterable that merges and filters deleted documents on the fly.

    Throws:
      `IOException`