#303 - Change beginTransaction() to use REQUIRED scope by default

src/main/java/com/avaje/ebean/Ebean.java

@@ -315,7 +315,10 @@ public final class Ebean {
   }
 
   /**
-   * Start a new explicit transaction.
+   * Start a transaction with 'REQUIRED' semantics.
+   * <p>
+   * With REQUIRED semantics if an active transaction already exists that transaction will be used.
+   * </p>
    * <p>
    * The transaction is stored in a ThreadLocal variable and typically you only
    * need to use the returned Transaction <em>IF</em> you wish to do things like

src/main/java/com/avaje/ebean/EbeanServer.java

@@ -509,7 +509,10 @@ public interface EbeanServer {
   Transaction createTransaction(TxIsolation isolation);
 
   /**
-   * Start a new explicit transaction putting it into a ThreadLocal.
+   * Start a transaction with 'REQUIRED' semantics.
+   * <p>
+   * With REQUIRED semantics if an active transaction already exists that transaction will be used.
+   * </p>
    * <p>
    * The transaction is stored in a ThreadLocal variable and typically you only
    * need to use the returned Transaction <em>IF</em> you wish to do things like

src/main/java/com/avaje/ebeaninternal/server/core/DefaultServer.java

@@ -756,16 +756,16 @@ public final class DefaultServer implements SpiEbeanServer {
   }
 
   /**
-   * Start a transaction.
+   * Start a transaction with 'REQUIRED' semantics.
+   * <p>
+   * If a transaction already exists that transaction will be used.
+   * </p>
    * <p>
    * Note that the transaction is stored in a ThreadLocal variable.
    * </p>
    */
   public Transaction beginTransaction() {
-    // start an explicit transaction
-    SpiTransaction t = transactionManager.createTransaction(true, -1);
-    transactionScopeManager.set(t);
-    return t;
+    return beginTransaction(TxScope.required());
   }
 
   public Transaction beginTransaction(TxScope scope) {