Description

Enhance the Jmix Reports add-on to support rendering spreadsheet-based report output (XLS, XLSX, ODS) directly inside a Vaadin Spreadsheet UI component instead of forcing file download.

The goal is to provide an Excel-like user experience within the Jmix UI for enterprise environments where working with saved spreadsheet files is restricted or prohibited.

Problem

Currently, spreadsheet reports are delivered as downloadable files.

In enterprise environments:

• Downloading files may be restricted by security policies
• Storing spreadsheet files locally may violate compliance rules
• Users still require Excel-like interaction (sorting, editing, formulas, navigation)
• Opening external office applications is often undesirable

There is no built-in way to render spreadsheet-based report output directly in the application UI.

Proposed Solution

Introduce an option to render generated spreadsheet reports inside a Vaadin Spreadsheet component.

Supported formats:

• XLS
• XLSX
• ODS (LibreOffice Calc)

The feature should:

• Generate report using existing spreadsheet template mechanism
• Load the resulting workbook into Vaadin Spreadsheet
• Display it in a dedicated report view/dialog
• Preserve formatting, formulas, merged cells, and styles

This should be available as:

• A report execution option (e.g., “Open in Spreadsheet”)
• Or a configurable output type in Report Designer

Integration Point

Extend the existing report execution pipeline:

• After spreadsheet report generation
• Instead of streaming file to browser
• Pass generated workbook to Vaadin Spreadsheet component

No changes to band/dataset logic are required.

Constraints

• Must reuse existing XLS/XLSX/ODS report engine
• Must not break existing file-download behavior
• Must respect report access rights and execution permissions
• Requires Vaadin Pro active subscription

Acceptance Criteria

• Spreadsheet reports can be rendered in Vaadin Spreadsheet
• Formatting, formulas, and multi-level structures preserved
• No mandatory file download
• Compatible with runtime and design-time reports
• Works with report access control and execution history