Package org.elasticsearch.index.mapper

Class SourceValueFetcher

java.lang.Object
org.elasticsearch.index.mapper.SourceValueFetcher
All Implemented Interfaces:
ValueFetcher
public abstract class SourceValueFetcher
extends java.lang.Object
implements ValueFetcher
An implementation of ValueFetcher that knows how to extract values from the document source. Most standard field mappers will use this class to implement value fetching.

Field types that handle arrays directly should instead use ArraySourceValueFetcher.

  • Constructor Details

    • SourceValueFetcher

      public SourceValueFetcher​(java.lang.String fieldName, SearchExecutionContext context)

    • SourceValueFetcher

      public SourceValueFetcher​(java.lang.String fieldName, SearchExecutionContext context, java.lang.Object nullValue)
      Parameters:
      fieldName - The name of the field.
      context - The query shard context
      nullValue - A optional substitute value if the _source value is 'null'.

  • Method Details

    • fetchValues

      public java.util.List<java.lang.Object> fetchValues​(SourceLookup lookup)
      Description copied from interface: ValueFetcher
      Given access to a document's _source, return this field's values. In addition to pulling out the values, they will be parsed into a standard form. For example numeric field mappers make sure to parse the source value into a number of the right type. Note that for array values, the order in which values are returned is undefined and should not be relied on.
      Specified by:
      fetchValues in interface ValueFetcher
      Parameters:
      lookup - a lookup structure over the document's source.
      Returns:
      a list a standardized field values.

    • parseSourceValue

      protected abstract java.lang.Object parseSourceValue​(java.lang.Object value)
      Given a value that has been extracted from a document's source, parse it into a standard format. This parsing logic should closely mirror the value parsing in FieldMapper.parseCreateField(org.elasticsearch.index.mapper.ParseContext) or FieldMapper.parse(org.elasticsearch.index.mapper.ParseContext).

    • identity

      public static SourceValueFetcher identity​(java.lang.String fieldName, SearchExecutionContext context, java.lang.String format)
      Creates a SourceValueFetcher that passes through source values unmodified.

    • toString

      public static SourceValueFetcher toString​(java.lang.String fieldName, SearchExecutionContext context, java.lang.String format)
      Creates a SourceValueFetcher that converts source values to strings.