Package search

Class PriorityQueueSearcher<State,Node extends SearchTreeNode<Node,State>,Frontier extends Frontiers.PriorityQueue<Node>>

java.lang.Object

search.GraphSearcher<State,Node,Frontier>

search.PriorityQueueSearcher<State,Node,Frontier>

Type Parameters:

State - Type representing elements of the search space.

Node - Type representing nodes in the search tree. Each node typically contains a reference to a State element.

Frontier - Type representing the (entire) search frontier (open set).

Direct Known Subclasses:

AStarFrontierSearcher

public class PriorityQueueSearcher<State,Node extends SearchTreeNode<Node,State>,Frontier extends Frontiers.PriorityQueue<Node>>
extends GraphSearcher<State,Node,Frontier>

Specialization of the generic GraphSearcher to use a priority queue structure for its frontier.

Constructor Summary

Constructors

Constructor	Description
PriorityQueueSearcher(Supplier<GoalChecker<Node>> goalCheckerFactory, Comparator<Node> prioritizer, Function<Comparator<Node>,Supplier<? extends Frontier>> frontierMetafactory, Function<Frontier,ExploredSet<Node>> exploredSetFactory, Function<State,Node> initializer)	This constructor allows the comparison function to be specified separately from the frontier-creation process.
PriorityQueueSearcher(Supplier<GoalChecker<Node>> goalCheckerFactory, Supplier<? extends Frontier> frontierFactory, Function<Frontier,ExploredSet<Node>> exploredSetFactory, Function<State,Node> initializer)	Primary constructor for this class.

Method Summary

Methods inherited from class search.GraphSearcher

debugExpansion, debugFrontier, debugFrontierAddition, debugFrontierExhausted, debugFrontierNonaddition, debugFrontierRemoval, debugGoalFound, debugInitialNode, getDebug, getLastAddedToFrontier, getLastExpandedFromFrontier, getLastNotAddedToFrontier, getLastUnexpandedInFrontier, search, setDebug, solvable

Methods inherited from class java.lang.Object

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

Constructor Details

PriorityQueueSearcher

public PriorityQueueSearcher(Supplier<GoalChecker<Node>> goalCheckerFactory, Comparator<Node> prioritizer, Function<Comparator<Node>,Supplier<? extends Frontier>> frontierMetafactory, Function<Frontier,ExploredSet<Node>> exploredSetFactory, Function<State,Node> initializer)

This constructor allows the comparison function to be specified separately from the frontier-creation process.

Parameters:

goalCheckerFactory - The get method of this object must return a predicate on tree nodes used to tell if they are goal nodes. Passed as-is to the primary constructor for this class, and thence to the parent constructor.

prioritizer - The method by which the priority queue ranks tree nodes. In Java's PriorityQueue implementation, the next element to be removed is the one ranked least by the Comparator.

frontierMetafactory - This function maps a Comparator for tree nodes to a Supplier of new, empty Frontier instances.

exploredSetFactory - Structure used to manage adding elements to the frontier, in particular for avoiing duplication. Passed as-is to the primary constructor for this class, and thence to the parent constructor.

initializer - Creates an initial tree node from a search space element. Passed as-is to the primary constructor for this class, and thence to the parent constructor.

PriorityQueueSearcher

public PriorityQueueSearcher(Supplier<GoalChecker<Node>> goalCheckerFactory, Supplier<? extends Frontier> frontierFactory, Function<Frontier,ExploredSet<Node>> exploredSetFactory, Function<State,Node> initializer)

Primary constructor for this class. Since the use of a priority queue is specified by the bounds on Frontier, this constructor simply passes its arguments to the superclass constructor. Other constructors for this class invoke this constructor.

Parameters:

goalCheckerFactory - The get method of this object must return a predicate on tree nodes used to tell if they are goal nodes.

frontierFactory - The get method of this object returns a new, empty Frontier instance. Note that the type bound on Factory requires that the generated objects conform to Frontiers.PriorityQueue.

exploredSetFactory - Structure used to manage adding elements to the frontier, in particular for avoiing duplication.

initializer - Creates an initial tree node from a search space element.