feat: add license validation

Author: zepfred

core/src/main/java/ai/timefold/solver/core/enterprise/License.java

@@ -0,0 +1,42 @@
+package ai.timefold.solver.core.enterprise;
+
+public final class License {
+
+    // TODO - Replace with the correct signed CA
+    public static final String CA = """
+            -----BEGIN CERTIFICATE-----
+            MIIFYTCCA0mgAwIBAgIUb39y+k9L8Nn+/5gLsOFkhBlpJ5MwDQYJKoZIhvcNAQEL
+            BQAwQDELMAkGA1UEBhMCQkUxETAPBgNVBAoMCFRpbWVmb2xkMR4wHAYDVQQDDBVU
+            aW1lZm9sZCBMaWNlbnNpbmcgQ0EwHhcNMjUxMjA5MTEwOTE3WhcNMzUxMjA3MTEw
+            OTE3WjBAMQswCQYDVQQGEwJCRTERMA8GA1UECgwIVGltZWZvbGQxHjAcBgNVBAMM
+            FVRpbWVmb2xkIExpY2Vuc2luZyBDQTCCAiIwDQYJKoZIhvcNAQEBBQADggIPADCC
+            AgoCggIBAMMzRBxF5B0KT/DlZ894bkoYD/nqK+qUoSC9P/E87yeX7oZiVfITGXjy
+            ZpJuG48zRH+7BLYG4ELHBixGI8OsLlGbAihPm70pn8QU/0aHJ9lSUDa5dsyuYmr7
+            gEhb45tHKgGscinCikjC8po3SGKIbgzqm5B/UmSWPoGeNHU0suYg37zlkwvyV1uj
+            rG1Pm2RJS35/U79bunyOpNjKmP6c75ccYMCG4VSdueF3et6bPiiYMY3I6mAS9anz
+            X9jKXgSJQR0uJPPUo9FfI91K8zLjhuze4BP4GAyHrIIdQgjRx1++90Vtgdfj9Odo
+            oQY64QDouO/nLNIGPV3K2cb5nQgtL41BpGfgFkkkDZZRua4GREDyW1LoPRD6wlGr
+            Ud0pnntL+KA7Ul75D5w4pqP5ZezuFVaHW/mT/gyDclei5QlebHJk/2Ibx1lrdwA7
+            MhD87aW1gfmiHUPbg6et+Oo/Dir8xja5SnZ0j008zUCXPVUk/BnCOPtEpCZ3aNIp
+            y3b8CQ7EIBU4VLE07B2tI6ZoArEXp+yRBCplxAUpmx88e9WaO9eLOFoDJnpHZcOz
+            QOer2uLmw7cesV8piuSGRB0aRWcW626Th6OgwGhYGHH2EXk1JZAO89nnEatpRDTW
+            0W1WTzH7q3yZ1eUwyy6WwZByTNYl9kyiXQaQ64v2Rh3hlobY3Dk7AgMBAAGjUzBR
+            MB0GA1UdDgQWBBQnum2seFZuX6i1e2nnqMY3IhxmBTAfBgNVHSMEGDAWgBQnum2s
+            eFZuX6i1e2nnqMY3IhxmBTAPBgNVHRMBAf8EBTADAQH/MA0GCSqGSIb3DQEBCwUA
+            A4ICAQCBCRZEfv2Iog2r28dFd7FrhwnFt3s2jh2BSYDTJMbVUPl52Mvwandjnem9
+            Rd+bIpWIP9wQrbGHuBpK5fBLq/HI6MrWGEI9a2ZI3hOVD8igAfU1nJedu3FKtTkk
+            xhfXc+VG6Djr3Uv5w4euYhdxV86jIUwQnuiJB3vZCVdZlNpyhm7D7f8eappOP0qf
+            syhGFhfJ0jm7FGVjwX8B8UMwsG1hvvrAiupubbTzRdRxqNc9zmjKGL6o+DDwVWSA
+            FPz3dOCTcV+w6R9IjH6KyYT7Xj6/lOOwMpzzhraB5KTxLOZf4N0s4PVF7C6PT1Z/
+            0hMYVCS28Gw56XjhPbMGtTHCgAx76w4uIuUNHJNa2DC/1nudxl1bQwxwkrCUC3Hh
+            iuGWUWAeoIbJrJQdPGDru+JKchkBafRdUpVvvRwcnjSw2cuKgP93elX+dHYrGfXm
+            mXbhHHQNixRAQj7i78vzoXQcEsJRvdWGFXkjt8yIVObRNtuMlZPmce+btFWq8cTl
+            ncuhpe+jwz9C0BjqVtAc8nH+eYPKFyGTDlsz7hzQb7gNrYTrNdhFCkpuhb+axfGp
+            ZPj0mbAaNlpYm/mlYt+jY5YmYJNomZKhxM8O09pOwLNrLbWUhrLczbeph1Iu33LE
+            KYb0W/hmsuvLXt6O5/fudgMzZ2oaVGKX4B89B2U8aYY28xyu/w==
+            -----END CERTIFICATE-----""";
+
+    private License() {
+        // Empty constructor
+    }
+}

core/src/main/java/ai/timefold/solver/core/enterprise/TimefoldSolverEnterpriseService.java

@@ -1,6 +1,7 @@
 package ai.timefold.solver.core.enterprise;
 
 import java.lang.reflect.InvocationTargetException;
+import java.security.cert.CertificateException;
 import java.util.Objects;
 import java.util.function.BiFunction;
 import java.util.function.Function;
@@ -57,7 +58,7 @@ static String identifySolverVersion() {
         return packaging + " " + version;
     }
 
-    private static String getVersionString(Class<?> clz) {
+    static String getVersionString(Class<?> clz) {
         var version = clz.getPackage().getImplementationVersion();
         return (version == null ? DEVELOPMENT_SNAPSHOT : "v" + version);
     }
@@ -86,8 +87,15 @@ static TimefoldSolverEnterpriseService loadOrFail(Feature feature) {
         var communityVersion = getVersionString(TimefoldSolverEnterpriseService.class);
         var enterpriseVersion = getVersionString(service.getClass());
         if (Objects.equals(communityVersion, enterpriseVersion)) { // Identical versions.
+            // We validate the user license at this point
+            try {
+                service.validateUserLicense();
+            } catch (CertificateException e) {
+                throw new IllegalStateException(e);
+            }
             return service;
         } else if (enterpriseVersion.equals(DEVELOPMENT_SNAPSHOT)) { // Don't enforce when running Enterprise tests.
+            // We do not validate the user license for development snapshots.
             return service;
         }
         throw new IllegalStateException("""
@@ -100,13 +108,25 @@ static TimefoldSolverEnterpriseService loadOrFail(Feature feature) {
     static <T> T buildOrDefault(Function<TimefoldSolverEnterpriseService, T> builder, Supplier<T> defaultValue) {
         try {
             var service = load();
+            var enterpriseVersion = getVersionString(service.getClass());
+            if (!enterpriseVersion.equals(DEVELOPMENT_SNAPSHOT)) {
+                // We validate the user license at this point
+                service.validateUserLicense();
+            }
             return builder.apply(service);
         } catch (ClassNotFoundException | InvocationTargetException | NoSuchMethodException | InstantiationException
                 | IllegalAccessException e) {
             return defaultValue.get();
+        } catch (CertificateException e) {
+            throw new IllegalStateException(e);
         }
     }
 
+    /**
+     * It performs a security validation to ensure that the user licenseo is valid.
+     */
+    void validateUserLicense() throws CertificateException;
+
     TopologicalOrderGraph buildTopologyGraph(int size);
 
     Class<? extends ConstraintProvider>