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Neo4j kernel is a lightweight, embedded Java database designed to
store data structured as graphs rather than tables. For more
information, see http://neo4j.org.
/*
* Copyright (c) "Neo4j"
* Neo4j Sweden AB [https://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 endNodes;
public MonoDirectionalTraversalDescription() {
this(
PathExpanders.allTypesAndDirections(),
Uniqueness.NODE_GLOBAL,
null,
Evaluators.all(),
InitialBranchState.NO_STATE,
BranchOrderingPolicies.PREORDER_DEPTH_FIRST,
null,
null);
}
private MonoDirectionalTraversalDescription(
PathExpander expander,
UniquenessFactory uniqueness,
Object uniquenessParameter,
PathEvaluator evaluator,
InitialBranchState initialState,
BranchOrderingPolicy branchOrdering,
Comparator sorting,
Collection endNodes) {
this.expander = expander;
this.uniqueness = uniqueness;
this.uniquenessParameter = uniquenessParameter;
this.evaluator = evaluator;
this.branchOrdering = branchOrdering;
this.sorting = sorting;
this.endNodes = endNodes;
this.initialState = initialState;
}
@Override
public Traverser traverse(Node startNode) {
return traverse(Collections.singletonList(startNode));
}
@Override
public Traverser traverse(Node... startNodes) {
return traverse(Arrays.asList(startNodes));
}
@Override
public Traverser traverse(final Iterable iterableStartNodes) {
return new DefaultTraverser(() -> {
MonoDirectionalTraverserIterator iterator = new MonoDirectionalTraverserIterator(
uniqueness.create(uniquenessParameter),
expander,
branchOrdering,
evaluator,
iterableStartNodes,
initialState,
uniqueness);
return sorting != null ? new SortingTraverserIterator(sorting, iterator) : iterator;
});
}
@Override
public TraversalDescription uniqueness(UniquenessFactory uniqueness) {
return new MonoDirectionalTraversalDescription(
expander, uniqueness, null, evaluator, initialState, branchOrdering, sorting, endNodes);
}
@Override
public TraversalDescription uniqueness(UniquenessFactory uniqueness, Object parameter) {
if (this.uniqueness == uniqueness
&& (uniquenessParameter == null ? parameter == null : uniquenessParameter.equals(parameter))) {
return this;
}
return new MonoDirectionalTraversalDescription(
expander, uniqueness, parameter, evaluator, initialState, branchOrdering, sorting, endNodes);
}
@Override
public TraversalDescription evaluator(Evaluator evaluator) {
return evaluator(new Evaluator.AsPathEvaluator(evaluator));
}
@Override
public TraversalDescription evaluator(PathEvaluator evaluator) {
if (this.evaluator == evaluator) {
return this;
}
nullCheck(evaluator, Evaluator.class, "RETURN_ALL");
return new MonoDirectionalTraversalDescription(
expander,
uniqueness,
uniquenessParameter,
addEvaluator(this.evaluator, evaluator),
initialState,
branchOrdering,
sorting,
endNodes);
}
protected static PathEvaluator addEvaluator(PathEvaluator existing, PathEvaluator toAdd) {
if (existing instanceof MultiEvaluator) {
return ((MultiEvaluator) existing).add(toAdd);
} else {
return existing == Evaluators.all() ? toAdd : new MultiEvaluator(existing, toAdd);
}
}
protected static void nullCheck(T parameter, Class parameterType, String defaultName) {
if (parameter == null) {
String typeName = parameterType.getSimpleName();
throw new IllegalArgumentException(
typeName + " may not be null, use " + typeName + "." + defaultName + " instead.");
}
}
@Override
public TraversalDescription order(BranchOrderingPolicy order) {
if (this.branchOrdering == order) {
return this;
}
return new MonoDirectionalTraversalDescription(
expander, uniqueness, uniquenessParameter, evaluator, initialState, order, sorting, endNodes);
}
@Override
public TraversalDescription depthFirst() {
return order(BranchOrderingPolicies.PREORDER_DEPTH_FIRST);
}
@Override
public TraversalDescription breadthFirst() {
return order(BranchOrderingPolicies.PREORDER_BREADTH_FIRST);
}
@Override
public TraversalDescription relationships(RelationshipType type) {
return relationships(type, Direction.BOTH);
}
@Override
public TraversalDescription relationships(RelationshipType type, Direction direction) {
if (expander instanceof StandardExpander) {
return expand(((StandardExpander) expander).add(type, direction));
}
throw new IllegalStateException("The current expander cannot be added to");
}
@Override
public TraversalDescription expand(PathExpander expander) {
if (expander.equals(this.expander)) {
return this;
}
return new MonoDirectionalTraversalDescription(
expander, uniqueness, uniquenessParameter, evaluator, initialState, branchOrdering, sorting, endNodes);
}
@Override
public TraversalDescription expand(PathExpander expander, InitialBranchState initialState) {
return new MonoDirectionalTraversalDescription(
expander, uniqueness, uniquenessParameter, evaluator, initialState, branchOrdering, sorting, endNodes);
}
@Override
public TraversalDescription sort(Comparator sorting) {
return new MonoDirectionalTraversalDescription(
expander, uniqueness, uniquenessParameter, evaluator, initialState, branchOrdering, sorting, endNodes);
}
@Override
public TraversalDescription reverse() {
return new MonoDirectionalTraversalDescription(
expander.reverse(),
uniqueness,
uniquenessParameter,
evaluator,
initialState.reverse(),
branchOrdering,
sorting,
endNodes);
}
}