Replaceable clock (#1428)

ENH: Use java.time.Clock for @WhenModified and @WhenCreated and allow it to be Replaceable for testing

src/main/java/io/ebean/config/ServerConfig.java

@@ -33,6 +33,7 @@ import io.ebean.util.StringHelper;
 import org.avaje.datasource.DataSourceConfig;
 
 import javax.sql.DataSource;
+import java.time.Clock;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -362,6 +363,11 @@ public class ServerConfig {
    */
   private String uuidStateFile = "ebean-uuid.state";
 
+  /**
+   * The clock used for setting the timestamps (e.g. @UpdatedTimestamp) on objects.
+   */
+  private Clock clock = Clock.systemUTC();
+
   private List<IdGenerator> idGenerators = new ArrayList<>();
   private List<BeanFindController> findControllers = new ArrayList<>();
   private List<BeanPersistController> persistControllers = new ArrayList<>();
@@ -507,6 +513,20 @@ public class ServerConfig {
 
   }
 
+  /**
+   * Get the clock used for setting the timestamps (e.g. @UpdatedTimestamp) on objects.
+   */
+  public Clock getClock() {
+    return clock;
+  }
+
+  /**
+   * Set the clock used for setting the timestamps (e.g. @UpdatedTimestamp) on objects.
+   */
+  public void setClock(final Clock clock) {
+    this.clock = clock;
+  }
+
   /**
    * Return the slow query time in millis.
    */

src/main/java/io/ebeaninternal/server/core/PersistRequestBean.java

@@ -1275,7 +1275,7 @@ public final class PersistRequestBean<T> extends PersistRequest implements BeanP
    */
   public long now() {
     if (now == 0) {
-      now = System.currentTimeMillis();
+      now = ebeanServer.getServerConfig().getClock().millis();
     }
     return now;
   }