public EventCondition withMessageActivity(String messageActivity) {
        setMessageActivity(messageActivity);
        return this;
    }
<p>
The message identifier (message_id) for the message to use when determining whether message events meet the
condition.
</p>

@param messageActivity
       The message identifier (message_id) for the message to use when determining whether message events meet
       the condition.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-pinpoint/src/main/java/com/amazonaws/services/pinpoint/model/EventCondition.java