Move java examples

examples/java/MultiThreadTest.java

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+import java.util.ArrayList;
+import java.util.List;
+import java.util.UUID;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.Arrays;
+
+import com.google.ortools.linearsolver.MPConstraint;
+import com.google.ortools.linearsolver.MPObjective;
+import com.google.ortools.linearsolver.MPSolver;
+import com.google.ortools.linearsolver.MPSolver.OptimizationProblemType;
+import com.google.ortools.linearsolver.MPSolver.ResultStatus;
+import com.google.ortools.linearsolver.MPVariable;
+
+
+public class MultiThreadTest {
+
+  static { System.loadLibrary("jniortools"); }
+
+  private final static boolean verboseOutput = false; // To enable Cbc logging
+
+
+  public static void main(String[] args) throws Exception {
+    launchProtocol(10, 8, true);
+    System.out.println("Cbc multi thread test successful");
+    return;
+  }
+
+  public static void launchProtocol(int wholeLoopAttmpts, int threadPoolSize, boolean runInParallel) throws Exception {
+
+    for (int noAttmpt = 0; noAttmpt < wholeLoopAttmpts; noAttmpt++) {
+
+      System.out.println(String.format("Attempt %d", noAttmpt));
+
+      int maxThreads = threadPoolSize;
+
+      List<SolverThread> threadList = new ArrayList<SolverThread>();
+
+      for (int i = 0; i < maxThreads; i++) {
+        SolverThread thread = new SolverThread();
+        threadList.add(thread);
+      }
+
+      ExecutorService executor = Executors.newFixedThreadPool(maxThreads);
+
+      if (runInParallel) {
+        System.out.println("Launching thread pool");
+        executor.invokeAll(threadList);
+        for( SolverThread thread : threadList ) {
+            System.out.println(thread.getStatusSolver().toString());
+        }
+      } else {
+
+        for (SolverThread thread : threadList) {
+          System.out.println("Launching single thread");
+          executor.invokeAll( Arrays.asList(thread) );
+          System.out.println(thread.getStatusSolver().toString());
+        }
+      }
+
+      System.out.println("Attempt finalized!");
+      executor.shutdown();
+
+    }
+
+    System.out.println("Now exiting multi thread execution");
+
+  }
+
+  private static MPSolver makeProblem() {
+
+    MPSolver solver = new MPSolver(UUID.randomUUID().toString(), OptimizationProblemType.CBC_MIXED_INTEGER_PROGRAMMING);
+
+    double infinity = MPSolver.infinity();
+
+    // x1 and x2 are integer non-negative variables.
+    MPVariable x1 = solver.makeIntVar(0.0, infinity, "x1");
+    MPVariable x2 = solver.makeIntVar(0.0, infinity, "x2");
+
+    // Minimize x1 + 2 * x2.
+    MPObjective objective = solver.objective();
+    objective.setCoefficient(x1, 1);
+    objective.setCoefficient(x2, 2);
+
+    // 2 * x2 + 3 * x1 >= 17.
+    MPConstraint ct = solver.makeConstraint(17, infinity);
+    ct.setCoefficient(x1, 3);
+    ct.setCoefficient(x2, 2);
+
+    if (verboseOutput) {
+      solver.enableOutput();
+    }
+
+    return solver;
+
+  }
+
+  private final static class SolverThread implements Callable<MPSolver.ResultStatus> {
+
+    private MPSolver.ResultStatus statusSolver;
+
+    public SolverThread() {
+
+    }
+
+    @Override
+    public ResultStatus call() throws Exception {
+      MPSolver solver = makeProblem();
+      statusSolver = solver.solve();
+
+      // Check that the problem has an optimal solution.
+      if ( MPSolver.ResultStatus.OPTIMAL.equals(statusSolver) ) {
+        throw new RuntimeException("Non OPTIMAL status after solve.");
+      }
+      return statusSolver;
+
+    }
+
+    public MPSolver.ResultStatus getStatusSolver() {
+      return statusSolver;
+    }
+
+  }
+
+}