Class OrdFieldSource
- java.lang.Object
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- org.apache.lucene.search.function.ValueSource
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- org.apache.lucene.search.function.OrdFieldSource
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- All Implemented Interfaces:
Serializable
public class OrdFieldSource extends ValueSource
Expert: obtains the ordinal of the field value from the default LuceneFieldcache
using getStringIndex().The native lucene index order is used to assign an ordinal value for each field value.
Example:
If there were only three field values: "apple","banana","pear"
then ord("apple")=1, ord("banana")=2, ord("pear")=3WARNING: ord() depends on the position in an index and can thus change when other documents are inserted or deleted, or if a MultiSearcher is used.
- See Also:
- Serialized Form
- WARNING: This API is experimental and might change in incompatible ways in the next release.
NOTE: with the switch in 2.9 to segment-based searching, if
getValues(org.apache.lucene.index.IndexReader)
is invoked with a composite (multi-segment) reader, this can easily cause double RAM usage for the values in the FieldCache. It's best to switch your application to pass only atomic (single segment) readers to this API.
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Constructor Summary
Constructors Constructor Description OrdFieldSource(String field)
Constructor for a certain field.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description String
description()
description of field, used in explain()boolean
equals(Object o)
Needed for possible caching of query results - used byValueSourceQuery.equals(Object)
.DocValues
getValues(IndexReader reader)
Return the DocValues used by the function query.int
hashCode()
Needed for possible caching of query results - used byValueSourceQuery.hashCode()
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Methods inherited from class org.apache.lucene.search.function.ValueSource
toString
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Field Detail
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field
protected String field
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Constructor Detail
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OrdFieldSource
public OrdFieldSource(String field)
Constructor for a certain field.- Parameters:
field
- field whose values order is used.
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Method Detail
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description
public String description()
Description copied from class:ValueSource
description of field, used in explain()- Specified by:
description
in classValueSource
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getValues
public DocValues getValues(IndexReader reader) throws IOException
Description copied from class:ValueSource
Return the DocValues used by the function query.- Specified by:
getValues
in classValueSource
- Parameters:
reader
- the IndexReader used to read these values. If any caching is involved, that caching would also be IndexReader based.- Throws:
IOException
- for any error.
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equals
public boolean equals(Object o)
Description copied from class:ValueSource
Needed for possible caching of query results - used byValueSourceQuery.equals(Object)
.- Specified by:
equals
in classValueSource
- See Also:
Object.equals(Object)
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hashCode
public int hashCode()
Description copied from class:ValueSource
Needed for possible caching of query results - used byValueSourceQuery.hashCode()
.- Specified by:
hashCode
in classValueSource
- See Also:
Object.hashCode()
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