Added docs regarding trigger's transaction.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/main/java/com/amazon/carbonado/Trigger.java b/src/main/java/com/amazon/carbonado/Trigger.java
index 6b7f9ea..df737e8 100644
--- a/src/main/java/com/amazon/carbonado/Trigger.java
+++ b/src/main/java/com/amazon/carbonado/Trigger.java
@@ -32,6 +32,18 @@ package com.amazon.carbonado;
  * "failed" events are run in the same order that the trigger was registered.

  * In other words, the last added trigger is at the outermost nesting level.

  *

+ * <p>Triggers always run within the same transaction as the triggering

+ * operation. The exact isolation level and update mode is outside the

+ * trigger's control. If an explicit isolation level or update mode is

+ * required, create a nested transaction within a trigger method. A trigger's

+ * nested transaction can also be defined span the entire triggering operation.

+ * To do this, enter the transaction in the "before" method, but return the

+ * transaction object without exiting it. The "after" method is responsible for

+ * exiting the transaction. It extracts (or simply casts) the transaction from

+ * the state object passed into it. When creating spanning transactions like

+ * this, it is critical that the "failed" method be defined to properly exit

+ * the transaction upon failure.

+ *

  * @author Brian S O'Neill

  */

 public abstract class Trigger<S> {