Class JoinQuery
- java.lang.Object
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- com.lucidworks.search.dsl.DslBase
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- com.lucidworks.search.dsl.request.DslCloneable
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- com.lucidworks.search.dsl.request.query.Query
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- com.lucidworks.search.dsl.request.query.JoinQuery
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public class JoinQuery extends Query
A query which joins or traces relationships between documents A query ("query") identifies preliminary or seed matches. The "from" field values in all of these matches are brought together into a set. The query then returns all documents whose "to" field contains a value from this set.The semantics mirror that of a SQL "nested query" of the form:
SELECT ... FROM ... WHERE $to IN (SELECT $from FROM ... WHERE $query)
In select circumstances, JoinQuery supports running the subquery on a separate collection. In these cases this collection can be specified using "fromIndex".
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Field Summary
Fields Modifier and Type Field Description static java.lang.String
TYPE
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description JoinQuery
clone()
java.util.List<Query>
getChildQueries()
Returns all the children of the query in question.java.lang.String
getFrom()
java.lang.String
getFromIndex()
Query
getQuery()
java.lang.String
getTo()
boolean
isEmptyQuery()
boolean
removeChildQuery(Query toRemove)
Remove 'toRemove', if 'toRemove' is currently a child of this Query object.boolean
replaceChildQuery(Query toReplace, Query replacement)
Swap 'replacement' in as a replacement, if 'toReplace' is currently a child of this Query object.-
Methods inherited from class com.lucidworks.search.dsl.request.DslCloneable
clone, deepClone
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Field Detail
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TYPE
public static final java.lang.String TYPE
- See Also:
- Constant Field Values
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Constructor Detail
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JoinQuery
public JoinQuery(java.lang.String from, java.lang.String to, java.lang.String fromIndex, Query query)
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Method Detail
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getTo
public java.lang.String getTo()
- Returns:
- the field name compared against the set of "from" field values. The overall result set contains documents whose "to" field contains any of the values in the "from" field of subquery matches.
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getFrom
public java.lang.String getFrom()
- Returns:
- the field name containing the values of interest in the subquery matches. All values in this field matched by the subquery are gathered into a set and used to identify the documents matching the overall query
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getFromIndex
public java.lang.String getFromIndex()
- Returns:
- a separate collection to run the subquery on. This option is only supported conditionally based on backend- specific requirements. If not specified, the subquery is run on the same collection that the "to" values are gathered in.
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getQuery
public Query getQuery()
- Returns:
- the subquery used to identify the documents whose "from" field values are of interest.
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getChildQueries
public java.util.List<Query> getChildQueries()
Description copied from class:Query
Returns all the children of the query in question. The returnedList
is provided as a copy - changes made to it do not impact the originating Query object in any way.- Specified by:
getChildQueries
in classQuery
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replaceChildQuery
public boolean replaceChildQuery(Query toReplace, Query replacement)
Description copied from class:Query
Swap 'replacement' in as a replacement, if 'toReplace' is currently a child of this Query object. Because a tree of Query objects might conceivably have repeated clauses, this method is implemented to test 'toReplace' using reference-equality instead of value-equality.- Specified by:
replaceChildQuery
in classQuery
- Returns:
- true if a replacement was made, false otherwise.
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removeChildQuery
public boolean removeChildQuery(Query toRemove)
Description copied from class:Query
Remove 'toRemove', if 'toRemove' is currently a child of this Query object. Because a tree of Query objects might conceivably have repeated clauses, this method is implemented to test 'toRemove' using reference-equality instead of value-equality.- Specified by:
removeChildQuery
in classQuery
- Returns:
- true if a removal was made, false otherwise.
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isEmptyQuery
public boolean isEmptyQuery()
- Specified by:
isEmptyQuery
in classQuery
- Returns:
- true if this query is now essentially "empty" (doesn't affect query logic at all) and can now be removed from the query tree. This can happen, for example, if all child queries were removed and the query logic depends on having at least one child query.
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