public void setOptInType(String optInType) {
        this.optInType = optInType;
    }
<p>
A value that specifies the type of opt-in request, or undoes an opt-in request. You can't undo an opt-in request
of type <code>immediate</code>.
</p>
<p>
Valid values:
</p>
<ul>
<li>
<p>
<code>immediate</code> - Apply the maintenance action immediately.
</p>
</li>
<li>
<p>
<code>next-maintenance</code> - Apply the maintenance action during the next maintenance window for the resource.
</p>
</li>
<li>
<p>
<code>undo-opt-in</code> - Cancel any existing <code>next-maintenance</code> opt-in requests.
</p>
</li>
</ul>

@param optInType
       A value that specifies the type of opt-in request, or undoes an opt-in request. You can't undo an opt-in
       request of type <code>immediate</code>.</p>
       <p>
       Valid values:
       </p>
       <ul>
       <li>
       <p>
       <code>immediate</code> - Apply the maintenance action immediately.
       </p>
       </li>
       <li>
       <p>
       <code>next-maintenance</code> - Apply the maintenance action during the next maintenance window for the
       resource.
       </p>
       </li>
       <li>
       <p>
       <code>undo-opt-in</code> - Cancel any existing <code>next-maintenance</code> opt-in requests.
       </p>
       </li>
aws-java-sdk-dms/src/main/java/com/amazonaws/services/databasemigrationservice/model/ApplyPendingMaintenanceActionRequest.java