How to filter by dimension using Google Analytics Data API (GA4) Java client library?

Question

I am trying to call Google Analytics Data API (GA4) using the Java client library and applying a dimension filter. This is the call which is working if I don't use the setDimensionFilter call:

RunReportRequest request =
    RunReportRequest.newBuilder()
        .setProperty(propertyId)
        .addDimensions(com.google.analytics.data.v1beta.Dimension.newBuilder().setName("pageLocation"))
        .addMetrics(com.google.analytics.data.v1beta.Metric.newBuilder().setName("screenPageViews"))
        .addMetrics(com.google.analytics.data.v1beta.Metric.newBuilder().setName("activeUsers"))
//        .setDimensionFilter(FilterExpression.newBuilder().setFilter(Filter.newBuilder().setStringFilter(
//             Filter.StringFilter.newBuilder()
//               .setMatchType(Filter.StringFilter.MatchType.FULL_REGEXP)
//               .setField(Descriptors.FieldDescriptor, "pageLocation")
//               .setValue("MY_REGEXP")
//               .build())))
        .addDateRanges(com.google.analytics.data.v1beta.DateRange.newBuilder()
        .setStartDate(startDate.toStringYYYYMMDDWithDashes())
        .setEndDate(endDate.toStringYYYYMMDDWithDashes()))
        .setKeepEmptyRows(true)
        .build();

I don't know how to use setDimensionFilter. If the usage which is commented in the previous code is correct, then the only thing missing is the call to setField. I don't know how to generate the Descriptors.FieldDescriptor instance (or even its meaning).

I have reviewed the client library javadoc, and also the code samples (which are really simple and unfortunately do not show any usage of setDimensionFilter).

Answer 1

The Descriptors.FieldDescriptor isn't part of the GA4 Data API and is an internal functionality of the protobuf framework

If you are trying to call this filter on a field with the name 'pageLocation' instead of using setField, I think you can do something like this

RunReportRequest request =
    RunReportRequest.newBuilder()
        .setProperty("properties/" + propertyId)
        .addDimensions(com.google.analytics.data.v1beta.Dimension.newBuilder().setName("pageLocation"))
        .addMetrics(com.google.analytics.data.v1beta.Metric.newBuilder().setName("screenPageViews"))
        .addMetrics(com.google.analytics.data.v1beta.Metric.newBuilder().setName("activeUsers"))
        .setDimensionFilter(FilterExpression.newBuilder()
            .setFilter(Filter.newBuilder()
                .setFieldName("pageLocation")
                .setStringFilter(Filter.StringFilter.newBuilder()
                    .setMatchType(Filter.StringFilter.MatchType.FULL_REGEXP)
                    .setValue("MY_REGEXP"))))
        .addDateRanges(com.google.analytics.data.v1beta.DateRange.newBuilder()
            .setStartDate("2020-03-31")
            .setEndDate("2021-03-31"))
        .build();

Also, if you want an additional example of how to use setDimensionFilter, here is another code example that might help

RunReportRequest request =
          RunReportRequest.newBuilder()
              .setProperty("properties/" + propertyId)
              .addDimensions(Dimension.newBuilder().setName("city"))
              .addMetrics(Metric.newBuilder().setName("activeUsers"))
              .addDateRanges(DateRange.newBuilder().setStartDate("2020-03-31").setEndDate("today"))
              .setDimensionFilter(FilterExpression.newBuilder()
                  .setAndGroup(FilterExpressionList.newBuilder()
                      .addExpressions(FilterExpression.newBuilder()
                          .setFilter(Filter.newBuilder()
                              .setFieldName("platform")
                              .setStringFilter(Filter.StringFilter.newBuilder()
                                  .setMatchType(Filter.StringFilter.MatchType.EXACT)
                                  .setValue("Android"))))
                      .addExpressions(FilterExpression.newBuilder()
                          .setFilter(Filter.newBuilder()
                              .setFieldName("eventName")
                              .setStringFilter(Filter.StringFilter.newBuilder()
                                  .setMatchType(Filter.StringFilter.MatchType.EXACT)
                                  .setValue("in_app_purchase"))))))
              .setMetricFilter(FilterExpression.newBuilder()
                  .setFilter(Filter.newBuilder()
                      .setFieldName("sessions")
                      .setNumericFilter(Filter.NumericFilter.newBuilder()
                          .setOperation(Filter.NumericFilter.Operation.GREATER_THAN)
                          .setValue(NumericValue.newBuilder()
                              .setInt64Value(1000)))))
              .build();