public AlarmHistoryItem withHistorySummary(String historySummary) {
        setHistorySummary(historySummary);
        return this;
    }
<p>
A summary of the alarm history, in text format.
</p>

@param historySummary
       A summary of the alarm history, in text format.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-cloudwatch/src/main/java/com/amazonaws/services/cloudwatch/model/AlarmHistoryItem.java