Package org.apache.lucene.monitor

Class QueryTree

java.lang.Object
org.apache.lucene.monitor.QueryTree
public abstract class QueryTree extends Object
A representation of a node in a query tree

Queries are analyzed and converted into an abstract tree, consisting of conjunction and disjunction nodes, and leaf nodes containing terms.

Terms may be collected from a node, which will use the weights of its sub-nodes to determine which paths are followed. The path may be changed by calling advancePhase(double)

  • Constructor Details

    • QueryTree

      public QueryTree()

  • Method Details

    • weight

      public abstract double weight()
      The weight of this node

    • collectTerms

      public abstract void collectTerms(BiConsumer<String,BytesRef> termCollector)
      Collect terms from the most highly-weighted path below this node

    • advancePhase

      public abstract boolean advancePhase(double minWeight)
      Find the next-most highly-weighted path below this node
      Parameters:
      minWeight - do not advance if the next path has a weight below this value
      Returns:
      false if there are no more paths above the minimum weight

    • toString

      public abstract String toString(int depth)
      Returns a string representation of the node
      Parameters:
      depth - the current depth of this node in the overall query tree

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • space

      protected String space(int width)
      Returns a string of width spaces

    • term

      public static QueryTree term(Term term, TermWeightor weightor)
      Returns a leaf node for a particular term

    • term

      public static QueryTree term(Term term, double weight)
      Returns a leaf node for a particular term and weight

      The weight must be greater than 0

    • term

      public static QueryTree term(String field, BytesRef term, double weight)
      Returns a leaf node for a particular term and weight

      The weight must be greater than 0

    • anyTerm

      public static QueryTree anyTerm(String reason)
      Returns a leaf node that will match any document

    • conjunction

      public static QueryTree conjunction(List<Function<TermWeightor,QueryTree>> children, TermWeightor weightor)
      Returns a conjunction of a set of child nodes

    • disjunction

      public static QueryTree disjunction(List<Function<TermWeightor,QueryTree>> children, TermWeightor weightor)
      Returns a disjunction of a set of child nodes