Package search

Class BreadthFirstSearcher<State,Node extends SearchTreeNode<Node,State>>

java.lang.Object

search.GraphSearcher<State,Node,Frontiers.Queue<Node>>

search.BreadthFirstSearcher<State,Node>

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.

Direct Known Subclasses:

BreadthFirstFinder

public class BreadthFirstSearcher<State,Node extends SearchTreeNode<Node,State>>
extends GraphSearcher<State,Node,Frontiers.Queue<Node>>

Specialization of the generic GraphSearcher to use a queue for its frontier, and thus erform breadth-first search.

Constructor Summary

Constructors

Constructor	Description
BreadthFirstSearcher(Predicate<State> stateChecker, Function<State,Node> initializer)	Constructor which uses a predicate on goals for checking success of a tree node, and which defaults to a HashSet on state elements for detecting previously-explored nodes.
BreadthFirstSearcher(Supplier<GoalChecker<Node>> goalCheckerFactory, Function<Frontiers.Queue<Node>,ExploredSet<Node>> exploredSetFactory, Function<State,Node> initializer)	Primary constructor for this class.
BreadthFirstSearcher(Supplier<GoalChecker<Node>> goalCheckerFactory, Function<State,Node> initializer)	Constructor which defaults to a HashSet on state elements for detecting previously-explored nodes.

Method Summary

Modifier and Type	Method	Description
static <S> BreadthFirstSearcher<S,Nodes.SimpleTreeNode<S>>	build(Predicate<S> stateChecker, Function<S,Iterable<S>> expander)

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

BreadthFirstSearcher

public BreadthFirstSearcher(Predicate<State> stateChecker, Function<State,Node> initializer)

Constructor which uses a predicate on goals for checking success of a tree node, and which defaults to a HashSet on state elements for detecting previously-explored nodes.

Parameters:

stateChecker - Success predicate on state elements.

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

BreadthFirstSearcher

public BreadthFirstSearcher(Supplier<GoalChecker<Node>> goalCheckerFactory, Function<State,Node> initializer)

Constructor which defaults to a HashSet on state elements for detecting previously-explored nodes.

Parameters:

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

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

BreadthFirstSearcher

public BreadthFirstSearcher(Supplier<GoalChecker<Node>> goalCheckerFactory, Function<Frontiers.Queue<Node>,ExploredSet<Node>> exploredSetFactory, Function<State,Node> initializer)

Primary constructor for this class. Passes its arguments to the superclass constructor, along with a factory for queue-based frontiers. 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.

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.

Method Details

build

public static <S> BreadthFirstSearcher<S,Nodes.SimpleTreeNode<S>> build(Predicate<S> stateChecker, Function<S,Iterable<S>> expander)