@Override
    public void applyProjection(int[][] projectFields) {
        this.projectedFields = new int[projectFields.length];
        for (int i = 0; i < projectFields.length; i++) {
            Preconditions.checkArgument(
                    projectFields[i].length == 1, "Don't support nested projection in iceberg source now.");
            this.projectedFields[i] = projectFields[i][0];
        }
    }
Flink Iceberg table source.
Copy from iceberg-flink:iceberg-flink-1.15:1.3.1
inlong-sort/sort-flink/sort-flink-v1.15/sort-connectors/iceberg/src/main/java/org/apache/inlong/sort/iceberg/source/IcebergTableSource.java