Package com.apple.foundationdb.record.lucene

Class LuceneIndexExpressions

java.lang.Object

com.apple.foundationdb.record.lucene.LuceneIndexExpressions

public class LuceneIndexExpressions
extends Object

The root expression of a LUCENE index specifies how select fields of a record are mapped to fields of a Lucene document.

The expression tree is made up of the following.
Structure

• concat includes multiple subexpressions in the index. Since these are flattened, order does not really matter.
• nest traverses a nested subrecord. By default, the name of the parent field is prepended to the names of descendent fields.

Fields

• field is a record field whose value is added to the index. By default, a field is indexed as a scalar value. That is, even a string with whitespace is a single token.
• function(lucene_text) annotates a document field as text so that it is tokenized in the Lucene index.
• function(lucene_stored) annotates a document field as additionally stored in the document so that its value is returned in searches.

Names
By default, the name of each field in the hierarchy of nested subrecords is included in the name of flattened fields. function(lucene_field_name) overrides this.

• value(null) skips adding any name prefix, introducing the possibility of flattened name collisions.
• field(key) allows another field to give the name. This is useful for map-like nested subrecords with well-known keys.

The expression tree can be walked in several different ways, either with an actual record to produce actual fields, or with record meta-data to determine what possible fields there are. Specifically,

• map a record into a document
• get a list of document field names
• validate the index expression at definition time
• compute correlated matching expressions for the query planner

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	LuceneIndexExpressions.DocumentDestination<T extends LuceneIndexExpressions.RecordSource<T>>	An actual document / document meta-data.
static class	LuceneIndexExpressions.DocumentFieldDerivation	Information about how a document field is derived from a record field.
static enum	LuceneIndexExpressions.DocumentFieldType	Possible types for document fields.
static interface	LuceneIndexExpressions.RecordSource<T extends LuceneIndexExpressions.RecordSource<T>>	An actual record / record meta-data.

Method Summary

Modifier and Type	Method	Description
static Map<String,org.apache.lucene.queryparser.flexible.standard.config.PointsConfig>	constructPointConfigMap(FDBRecordStoreBase<?> store, Index index)	Constructs a point-config map for a given Index fields.
static Map<String,LuceneIndexExpressions.DocumentFieldDerivation>	getDocumentFieldDerivations(KeyExpression root, Descriptors.Descriptor recordType)	Get the derivations of known document fields.
static Map<String,LuceneIndexExpressions.DocumentFieldDerivation>	getDocumentFieldDerivations(Index index, RecordMetaData metadata)
static <T extends LuceneIndexExpressions.RecordSource<T>> void	getFields(KeyExpression root, T source, LuceneIndexExpressions.DocumentDestination<T> destination, String fieldNamePrefix)	Interpret the index key expression, either concretely for an actual record, or symbolically using meta-data.
static <T extends LuceneIndexExpressions.RecordSource<T>> void	getFieldsRecursively(KeyExpression expression, T source, LuceneIndexExpressions.DocumentDestination<T> destination, String fieldNamePrefix, int keyIndex, int groupingCount, List<Integer> overriddenKeyRanges)
static void	validate(KeyExpression root, Descriptors.Descriptor recordType)	Validate this key expression by interpreting it against the given meta-data.

Methods inherited from class java.lang.Object

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

Method Details

validate

public static void validate(@Nonnull
 KeyExpression root,
 @Nonnull
 Descriptors.Descriptor recordType)

Validate this key expression by interpreting it against the given meta-data.

Parameters:

root - the LUCENE index root expresison

recordType - Protobuf meta-data for record type

getDocumentFieldDerivations

@Nonnull
public static Map<String,LuceneIndexExpressions.DocumentFieldDerivation> getDocumentFieldDerivations(@Nonnull
 Index index,
 @Nonnull
 RecordMetaData metadata)

getDocumentFieldDerivations

public static Map<String,LuceneIndexExpressions.DocumentFieldDerivation> getDocumentFieldDerivations(@Nonnull
 KeyExpression root,
 @Nonnull
 Descriptors.Descriptor recordType)

Get the derivations of known document fields.

Parameters:

root - the LUCENE index root expression

recordType - Protobuf meta-data for record type

Returns:

a map of document field names to LuceneIndexExpressions.DocumentFieldDerivation

constructPointConfigMap

@Nonnull
public static Map<String,org.apache.lucene.queryparser.flexible.standard.config.PointsConfig> constructPointConfigMap(@Nonnull
 FDBRecordStoreBase<?> store,
 @Nonnull
 Index index)

Constructs a point-config map for a given Index fields.

Parameters:

store - The record store, used to retrieve metadata.

index - The index.

Returns:

a mapping between an index field name and its PointsConfig.

getFields

@Nonnull
public static <T extends LuceneIndexExpressions.RecordSource<T>>
void getFields(@Nonnull
 KeyExpression root,
 @Nonnull
 T source,
 @Nonnull
 LuceneIndexExpressions.DocumentDestination<T> destination,
 @Nullable
 String fieldNamePrefix)

Interpret the index key expression, either concretely for an actual record, or symbolically using meta-data.

Type Parameters:

T - specific kind of LuceneIndexExpressions.RecordSource

Parameters:

root - the LUCENE index root expresison

source - the record / record meta-data

destination - the document / document meta-data

fieldNamePrefix - prefix for generated field names

getFieldsRecursively

public static <T extends LuceneIndexExpressions.RecordSource<T>>
void getFieldsRecursively(@Nonnull
 KeyExpression expression,
 @Nonnull
 T source,
 @Nonnull
 LuceneIndexExpressions.DocumentDestination<T> destination,
 @Nullable
 String fieldNamePrefix,
 int keyIndex,
 int groupingCount,
 @Nonnull
 List<Integer> overriddenKeyRanges)