Add SimpleRoutingProgram.java

ortools/constraint_solver/samples/SimpleRoutingProgram.java

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+// Copyright 2018 Google LLC
+// 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.
+
+// [START program]
+// [START import]
+import java.util.logging.Logger;
+import com.google.ortools.constraintsolver.Assignment;
+import com.google.ortools.constraintsolver.FirstSolutionStrategy;
+import com.google.ortools.constraintsolver.LongLongToLong;
+import com.google.ortools.constraintsolver.RoutingIndexManager;
+import com.google.ortools.constraintsolver.RoutingModel;
+import com.google.ortools.constraintsolver.RoutingSearchParameters;
+import com.google.ortools.constraintsolver.main;
+// [END import]
+
+class SimpleRoutingProgram {
+  static {
+    System.loadLibrary("jniortools");
+  }
+
+  private static Logger logger =
+    Logger.getLogger(SimpleRoutingProgram.class.getName());
+
+  static void SimpleRoutingProgram() {
+    // Instantiate the data problem.
+    // [START data]
+    final int num_location = 5;
+    final int num_vehicles = 1;
+    final int depot = 0;
+    // [END data]
+
+    // Create Routing Index Manager
+    // [START index_manager]
+    RoutingIndexManager manager = new RoutingIndexManager(num_location, num_vehicles, depot);
+    // [END index_manager]
+
+    // Create Routing Model.
+    // [START routing_model]
+    RoutingModel routing = new RoutingModel(manager);
+    // [END routing_model]
+
+    // Define cost of each arc.
+    // [START arc_cost]
+    routing.setArcCostEvaluatorOfAllVehicles(
+        routing.registerTransitCallback(
+          new LongLongToLong() {
+            @Override
+            public long run(long from_node, long to_node) {
+              return 1;
+            }
+          }));
+    // [END arc_cost]
+
+    // Setting first solution heuristic.
+    // [START parameters]
+    RoutingSearchParameters search_parameters =
+        RoutingSearchParameters.newBuilder()
+            .mergeFrom(main.defaultRoutingSearchParameters())
+            .setFirstSolutionStrategy(FirstSolutionStrategy.Value.PATH_CHEAPEST_ARC)
+            .build();
+    // [END parameters]
+
+    // Solve the problem.
+    // [START solve]
+    Assignment solution = routing.solveWithParameters(search_parameters);
+    // [END solve]
+
+    // Print solution on console.
+    // [START print_solution]
+    logger.info("Objective: " + solution.objectiveValue());
+    // Inspect solution.
+    long index = routing.start(0);
+    logger.info("Route for Vehicle 0:");
+    long route_distance = 0;
+    String route = "";
+    while (routing.isEnd(index) == false) {
+      route += manager.indexToNode(index) + " -> ";
+      long previous_index = index;
+      index = solution.value(routing.nextVar(index));
+      route_distance += routing.getArcCostForVehicle(previous_index, index, 0);
+    }
+    route += manager.indexToNode(index);
+    logger.info(route);
+    logger.info("Distance of the route: " + route_distance + "m");
+    // [END print_solution]
+  }
+
+  public static void main(String[] args) throws Exception {
+    SimpleRoutingProgram();
+  }
+}
+// [END program]