public ParticipatingGateways withGatewayList(GatewayListItem... gatewayList) {
        if (this.gatewayList == null) {
            setGatewayList(new java.util.ArrayList<GatewayListItem>(gatewayList.length));
        }
        for (GatewayListItem ele : gatewayList) {
            this.gatewayList.add(ele);
        }
        return this;
    }
<p>
The list of gateways that you want to use for sending the downlink data traffic.
</p>
<p>
<b>NOTE:</b> This method appends the values to the existing list (if any). Use
{@link #setGatewayList(java.util.Collection)} or {@link #withGatewayList(java.util.Collection)} if you want to
override the existing values.
</p>

@param gatewayList
       The list of gateways that you want to use for sending the downlink data traffic.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-iotwireless/src/main/java/com/amazonaws/services/iotwireless/model/ParticipatingGateways.java