private Application applyClusterField(String id, Inspector clusterObject) {
        Optional<Cluster> cluster = application.cluster(ClusterSpec.Id.from(id));
        if (cluster.isEmpty()) return application;
        Inspector bcpGroupInfoObject = clusterObject.field("bcpGroupInfo");
        if ( ! bcpGroupInfoObject.valid()) return application;
        double queryRate = bcpGroupInfoObject.field("queryRate").asDouble();
        double growthRateHeadroom = bcpGroupInfoObject.field("growthRateHeadroom").asDouble();
        double cpuCostPerQuery = bcpGroupInfoObject.field("cpuCostPerQuery").asDouble();
        return application.with(cluster.get().with(new BcpGroupInfo(queryRate, growthRateHeadroom, cpuCostPerQuery)));
    }
Returns the application in its current state (patch applied or not)
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/ApplicationPatcher.java