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
.
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Constructor Summary
Constructors Constructor Description SourceValueFetcher(java.lang.String fieldName, SearchExecutionContext context)
SourceValueFetcher(java.lang.String fieldName, SearchExecutionContext context, java.lang.Object nullValue)
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Method Summary
Modifier and Type Method Description java.util.List<java.lang.Object>
fetchValues(SourceLookup lookup)
Given access to a document's _source, return this field's values.static SourceValueFetcher
identity(java.lang.String fieldName, SearchExecutionContext context, java.lang.String format)
Creates aSourceValueFetcher
that passes through source values unmodified.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.static SourceValueFetcher
toString(java.lang.String fieldName, SearchExecutionContext context, java.lang.String format)
Creates aSourceValueFetcher
that converts source values to strings.Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface org.elasticsearch.index.mapper.ValueFetcher
setNextReader
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Constructor Details
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SourceValueFetcher
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SourceValueFetcher
public SourceValueFetcher(java.lang.String fieldName, SearchExecutionContext context, java.lang.Object nullValue)- Parameters:
fieldName
- The name of the field.context
- The query shard contextnullValue
- A optional substitute value if the _source value is 'null'.
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Method Details
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fetchValues
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 interfaceValueFetcher
- Parameters:
lookup
- a lookup structure over the document's source.- Returns:
- a list a standardized field values.
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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 inFieldMapper.parseCreateField(org.elasticsearch.index.mapper.ParseContext)
orFieldMapper.parse(org.elasticsearch.index.mapper.ParseContext)
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identity
public static SourceValueFetcher identity(java.lang.String fieldName, SearchExecutionContext context, java.lang.String format)Creates aSourceValueFetcher
that passes through source values unmodified. -
toString
public static SourceValueFetcher toString(java.lang.String fieldName, SearchExecutionContext context, java.lang.String format)Creates aSourceValueFetcher
that converts source values to strings.
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