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GraphExample.java
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GraphExample.java
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/*
* Copyright (C) 2017-2024 HERE Europe B.V.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* SPDX-License-Identifier: Apache-2.0
* License-Filename: LICENSE
*/
package com.here.platform.example.location.java.standalone;
import static java.util.Comparator.comparingDouble;
import static java.util.stream.StreamSupport.stream;
import com.here.platform.data.client.base.javadsl.BaseClient;
import com.here.platform.data.client.base.javadsl.BaseClientJava;
import com.here.platform.location.core.geospatial.ElementProjection;
import com.here.platform.location.core.geospatial.GeoCoordinate;
import com.here.platform.location.core.geospatial.javadsl.ProximitySearch;
import com.here.platform.location.core.graph.javadsl.DirectedGraph;
import com.here.platform.location.inmemory.graph.Edge;
import com.here.platform.location.inmemory.graph.Vertex;
import com.here.platform.location.integration.optimizedmap.OptimizedMap;
import com.here.platform.location.integration.optimizedmap.OptimizedMapLayers;
import com.here.platform.location.integration.optimizedmap.dcl2.javadsl.OptimizedMapCatalog;
import com.here.platform.location.integration.optimizedmap.geospatial.javadsl.ProximitySearches;
import com.here.platform.location.integration.optimizedmap.graph.javadsl.Graphs;
import java.util.*;
public final class GraphExample {
public static void main(final String[] args) {
final int nodesToVisit = 20;
final BaseClient baseClient = BaseClientJava.instance();
try {
final OptimizedMapLayers optimizedMap =
OptimizedMapCatalog.from(OptimizedMap.v2.HRN)
.usingBaseClient(baseClient)
.newInstance()
.version(1293L);
final GeoCoordinate pariserPlatz = new GeoCoordinate(52.516364, 13.378870);
final Graphs graphs = new Graphs(optimizedMap);
final DirectedGraph<Vertex, Edge> graph = graphs.forward();
final ProximitySearches proximitySearches = new ProximitySearches(optimizedMap);
final ProximitySearch<GeoCoordinate, Vertex> proximitySearch = proximitySearches.vertices();
final Optional<ElementProjection<Vertex>> startVertex =
stream(proximitySearch.search(pariserPlatz, 50).spliterator(), false)
.min(comparingDouble(ElementProjection::distanceInMeters));
startVertex.ifPresent(
v -> breadthFirstVisit(graph, v.element(), nodesToVisit).forEach(System.out::println));
} finally {
baseClient.shutdown();
}
}
private static Iterable<Vertex> breadthFirstVisit(
final DirectedGraph<Vertex, Edge> graph, final Vertex root, int numberOfNodes) {
final Set<Vertex> visited = new LinkedHashSet<>();
final Queue<Vertex> frontier = new LinkedList<>();
frontier.add(root);
while (numberOfNodes >= 0 && !frontier.isEmpty()) {
final Vertex elem = frontier.remove();
visited.add(elem);
graph
.getOutEdgeIterator(elem)
.forEachRemaining(
e -> {
final Vertex v = graph.getTarget(e);
if (!visited.contains(v)) {
frontier.add(v);
}
});
numberOfNodes -= 1;
}
return visited;
}
}