public void getSummary(Context ctx) {
    int totalCatalog = manager.getTotalCatalog();
    int totalTableCount = manager.getTotalTableCount();
    long totalDataSize = manager.getTotalDataSize();
    int totalCpu = manager.getTotalCpu();
    long totalMemory = manager.getTotalMemory();

    OverviewSummary overviewSummary =
        new OverviewSummary(totalCatalog, totalTableCount, totalDataSize, totalCpu, totalMemory);
    ctx.json(OkResponse.of(overviewSummary));
  }
The controller that handles overview page requests.
amoro-ams/src/main/java/org/apache/amoro/server/dashboard/controller/OverviewController.java