com.lucidworks.search.dsl.request.query.walk

Class QueryTreeWalker

java.lang.Object

com.lucidworks.search.dsl.DslBase

com.lucidworks.search.dsl.request.query.walk.QueryTreeWalker

public class QueryTreeWalker
extends DslBase

Walks a tree of Query objects, performing a user-specified callback at each "node" in the tree.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	QueryTreeWalker.QueryWalkContext

Constructor Summary

Constructors

Constructor and Description
QueryTreeWalker()

Method Summary

Modifier and Type	Method and Description
static Stream<QueryTreeWalker.QueryWalkContext>	contextStream(QueryDefinition qd) Creates a stream populated by a depth-first walk of the query-tree Callers should beware using the QueryTreeWalker.QueryWalkContext to modify the links between queries as tree branches may be orphaned or dropped from iteration as a result.
void	depthFirstWalk(QueryDefinition queryDefinition, Function<QueryTreeWalker.QueryWalkContext,QueryTreeAction> perNodeAction) Performs a depth-first walk of the main query in the specified QueryDefinition Our walk processes the whole tree by default.

Methods inherited from class com.lucidworks.search.dsl.DslBase

equals, hashCode, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

QueryTreeWalker

public QueryTreeWalker()

Method Detail

depthFirstWalk

public void depthFirstWalk(QueryDefinition queryDefinition,
                           Function<QueryTreeWalker.QueryWalkContext,QueryTreeAction> perNodeAction)

Performs a depth-first walk of the main query in the specified QueryDefinition Our walk processes the whole tree by default. However, if the provided callback replaces the Query currently being processed, the walk skips over any children in that subtree to limit the risk of accidental infinite-recursion or double-visiting.

Parameters:

queryDefinition - the DSL definition containing the query-tree to walk

perNodeAction - a Function to process each node as it's visited. If any modifications are being made to the node (or its children), the Function can return a new query object which should replace the current query's position within the tree. Function's that don't modify the tree in any way can return the Query object attached to the current QueryWalkContext

contextStream

public static Stream<QueryTreeWalker.QueryWalkContext> contextStream(QueryDefinition qd)

Creates a stream populated by a depth-first walk of the query-tree Callers should beware using the QueryTreeWalker.QueryWalkContext to modify the links between queries as tree branches may be orphaned or dropped from iteration as a result.