public AttributeAction getAction() {
        return action;
    }
Used to update an attribute. Each instance of AttributeUpdate includes the
name, action and new value to be used for modifying the attribute.
<p>
Typical usages:
<blockquote>
<code>new AttributeUpdate("strAttr").put("attrValue");</code>
<p>
<code>new AttributeUpdate("intAttr").addNumeric(42);</code>
<p>
...
</blockquote>
<p>
See http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/
API_UpdateItem.html#DDB-UpdateItem-request-AttributeUpdates
aws-java-sdk-dynamodb/src/main/java/com/amazonaws/services/dynamodbv2/document/AttributeUpdate.java