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/*
* Copyright (c) "Neo4j"
* Neo4j Sweden AB [http://neo4j.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see
* TraversalDescription td = new TraversalDescriptionImpl();
* td.depthFirst();
*
*
* is not going to modify td. you will need to reassign td, like
*
*
* td = td.depthFirst();
*
*
* When all the rules and behaviors have been described the traversal is started
* by using {@link #traverse(Node)} where a starting node is supplied. The
* {@link Traverser} that is returned is then used to step through the graph,
* and return the positions that matches the rules.
*/
@PublicApi
public interface TraversalDescription
{
/**
* Sets the {@link UniquenessFactory} for creating the
* {@link UniquenessFilter} to use.
*
* @param uniqueness the {@link UniquenessFactory} the creator
* of the desired {@link UniquenessFilter} to use.
* @return a new traversal description with the new modifications.
*/
TraversalDescription uniqueness( UniquenessFactory uniqueness );
/**
* Sets the {@link UniquenessFactory} for creating the
* {@link UniquenessFilter} to use. It also accepts an extra parameter
* which is mandatory for certain uniquenesses.
*
* @param uniqueness the {@link UniquenessFactory} the creator
* of the desired {@link UniquenessFilter} to use.
* @param parameter an extra parameter
* which is mandatory for certain uniquenesses.
* @return a new traversal description with the new modifications.
*/
TraversalDescription uniqueness( UniquenessFactory uniqueness, Object parameter );
/**
* Adds {@code evaluator} to the list of evaluators which will control the
* behavior of the traversal. Each {@link Evaluator} can decide whether or
* not to include a position in the traverser result, i.e. return it from
* the {@link Traverser} iterator and also whether to continue down that
* path or to prune, so that the traverser won't continue further down that
* path.
*
* Multiple {@link Evaluator}s can be added. For a path to be included in
* the result, all evaluators must agree to include it, i.e. returning
* either {@link Evaluation#INCLUDE_AND_CONTINUE} or
* {@link Evaluation#INCLUDE_AND_PRUNE}. For making the traversal continue
* down that path all evaluators must agree to continue from that path, i.e.
* returning either {@link Evaluation#INCLUDE_AND_CONTINUE} or
* {@link Evaluation#EXCLUDE_AND_CONTINUE}.
*
* @param evaluator the {@link Evaluator} to add to the traversal
* @return a new traversal description with the new modifications.
*/
TraversalDescription evaluator( Evaluator evaluator );
/**
* Adds {@code evaluator} to the list of evaluators which will control the
* behavior of the traversal. Each {@link PathEvaluator} can decide whether or
* not to include a position in the traverser result, i.e. return it from
* the {@link Traverser} iterator and also whether to continue down that
* path or to prune, so that the traverser won't continue further down that
* path.
*
* Multiple {@link PathEvaluator}s can be added. For a path to be included in
* the result, all evaluators must agree to include it, i.e. returning
* either {@link Evaluation#INCLUDE_AND_CONTINUE} or
* {@link Evaluation#INCLUDE_AND_PRUNE}. For making the traversal continue
* down that path all evaluators must agree to continue from that path, i.e.
* returning either {@link Evaluation#INCLUDE_AND_CONTINUE} or
* {@link Evaluation#EXCLUDE_AND_CONTINUE}.
*
* @param evaluator the {@link PathEvaluator} to add to the traversal
* @return a new traversal description with the new modifications.
*/
TraversalDescription evaluator( PathEvaluator evaluator );
/**
* Sets the {@link BranchOrderingPolicy} to use. A {@link BranchSelector}
* is the basic decisions in the traversal of "where to go next".
* Examples of default implementations are "breadth first" and
* "depth first", which can be set with convenience methods
* {@link #breadthFirst()} and {@link #depthFirst()}.
*
* @param selector the factory which creates the {@link BranchSelector}
* to use with the traversal.
* @return a new traversal description with the new modifications.
*/
TraversalDescription order( BranchOrderingPolicy selector );
/**
* A convenience method for {@link #order(BranchOrderingPolicy)}
* where a "preorder depth first" selector is used. Positions which are
* deeper than the current position will be returned before positions on
* the same depth. See http://en.wikipedia.org/wiki/Depth-first_search
* @return a new traversal description with the new modifications.
*/
TraversalDescription depthFirst();
/**
* A convenience method for {@link #order(BranchOrderingPolicy)}
* where a "preorder breadth first" selector is used. All positions with
* the same depth will be returned before advancing to the next depth.
* See http://en.wikipedia.org/wiki/Breadth-first_search
* @return a new traversal description with the new modifications.
*/
TraversalDescription breadthFirst();
/**
* Adds {@code type} to the list of relationship types to traverse.
* There's no priority or order in which types to traverse.
*
* @param type the {@link RelationshipType} to add to the list of types
* to traverse.
* @return a new traversal description with the new modifications.
*/
TraversalDescription relationships( RelationshipType type );
/**
* Adds {@code type} to the list of relationship types to traverse in
* the given {@code direction}. There's no priority or order in which
* types to traverse.
*
* @param type the {@link RelationshipType} to add to the list of types
* to traverse.
* @param direction the {@link Direction} to traverse this type of
* relationship in.
* @return a new traversal description with the new modifications.
*/
TraversalDescription relationships( RelationshipType type,
Direction direction );
/**
* Sets the {@link PathExpander} as the expander of relationships,
* discarding all previous calls to
* {@link #relationships(RelationshipType)} and
* {@link #relationships(RelationshipType, Direction)} or any other expand method.
*
* @param expander the {@link PathExpander} to use.
* @return a new traversal description with the new modifications.
*/
TraversalDescription expand( PathExpander expander );
/**
* Sets the {@link PathExpander} as the expander of relationships,
* discarding all previous calls to
* {@link #relationships(RelationshipType)} and
* {@link #relationships(RelationshipType, Direction)} or any other expand method.
* The supplied {@link InitialBranchState} will provide the initial traversal branches
* with state values which flows down throughout the traversal and can be changed
* for child branches by the {@link PathExpander} at any level.
*
* @param expander the {@link PathExpander} to use.
* @param initialState factory for supplying the initial traversal branches with
* state values potentially used by the {@link PathExpander}.
* @param the type of the state object
* @return a new traversal description with the new modifications.
*/
TraversalDescription expand( PathExpander expander, InitialBranchState initialState );
/**
* @param comparator the {@link Comparator} to use for sorting the paths.
* @return the paths from this traversal sorted according to {@code comparator}.
*/
TraversalDescription sort( Comparator comparator );
/**
* Creates an identical {@link TraversalDescription}, although reversed in
* how it traverses the graph.
*
* @return a new traversal description with the new modifications.
*/
TraversalDescription reverse();
/**
* Traverse from a single start node based on all the rules and behavior
* in this description. A {@link Traverser} is returned which is
* used to step through the graph and getting results back. The traversal
* is not guaranteed to start before the Traverser is used.
*
* @param startNode {@link Node} to start traversing from.
* @return a {@link Traverser} used to step through the graph and to get
* results from.
*/
Traverser traverse( Node startNode );
/**
* Traverse from a set of start nodes based on all the rules and behavior
* in this description. A {@link Traverser} is returned which is
* used to step through the graph and getting results back. The traversal
* is not guaranteed to start before the Traverser is used.
*
* @param startNodes {@link Node}s to start traversing from.
* @return a {@link Traverser} used to step through the graph and to get
* results from.
*/
Traverser traverse( Node... startNodes );
/**
* Traverse from a iterable of start nodes based on all the rules and behavior
* in this description. A {@link Traverser} is returned which is
* used to step through the graph and getting results back. The traversal
* is not guaranteed to start before the Traverser is used.
*
* @param iterableStartNodes {@link Node}s to start traversing from.
* @return a {@link Traverser} used to step through the graph and to get
* results from.
*/
Traverser traverse( Iterable iterableStartNodes );
}