Exporting viewObject data in text file using af:fileDownloadActionListener in Oracle ADF (12.1.3)

Hello All
This post is about using af:fileDownloadActionListener to generate file on run-time, suppose i have a viewObject and i want to export it's data in CSV or plain text so for this requirement we can generate file at run-time and send it to client UI to download

What is af:fileDownloadActionListener-
as per oracle docs-
The fileDownloadActionListener tag is a declarative way to allow an action source (<commandButton>, <commandLink>, etc.) to programatically send the contents of a file to the user, optionally with a specific content type and filename. Since file downloads must be processed with an ordinary request - not XMLHttp AJAX requests - this tag forces partialSubmit to be false on the parent component, if it supports that attribute.
The fileDownloadActionListener uses the native (browser built-in) filedownload popup, so this popup cannot be configured.

In this post i am using Departments table of HR schema

• Prepare model part using Departments table and drop it on page as a table and add a button to UI for downloading





• drop af:fileDownloadActionListener as child of button and set it's property as contentType, method , fileName 





• Now see code written in download Listener-



    /**Method to get BindingsContainer for current page
     * @return
     */
    public BindingContainer getBindingsCont() {
        return BindingContext.getCurrent().getCurrentBindingsEntry();
    }

    /**Method to download ViewObject's data in plain text file
     * @param facesContext
     * @param outputStream
     * @throws UnsupportedEncodingException
     * @throws IOException
     */
    public void fileDownloadListener(FacesContext facesContext,
                                     OutputStream outputStream) throws UnsupportedEncodingException, IOException {
        OutputStreamWriter w = new OutputStreamWriter(outputStream, "UTF-8");
        //Get itertaor from bindings
        DCIteratorBinding deptIter = (DCIteratorBinding) getBindingsCont().get("Departments1Iterator");
        //Get ViewObject from Iterator
        ViewObjectImpl vo = (ViewObjectImpl) deptIter.getViewObject();
        ViewAttributeDefImpl[] attrDefs = vo.getViewAttributeDefImpls();
        int count = 0;
        RowSetIterator rsi = vo.createRowSetIterator(null);
        while (rsi.hasNext()) {
            Row nextRow = rsi.next();
            if (nextRow != null) {
                // Code to iterate over ViewObject's column to get all columns value at runtime
                for (ViewAttributeDefImpl attrDef : attrDefs) {
                    byte attrKind =
                        attrDefs[count].getAttributeKind(); //checks attribute kind for each element in an array of AttributeDefs
                    if (attrKind != AttributeDef.ATTR_ASSOCIATED_ROW &&
                        attrKind != AttributeDef.ATTR_ASSOCIATED_ROWITERATOR) {
                        String columnName = attrDef.getName();
                        w.write(columnName + " - " + nextRow.getAttribute(columnName) + "  ");
                    }
                }
                // Code to create new line text line for new Row
                w.write(System.getProperty("line.separator"));
            }
        }
        //Flush the writer after wrting file
        w.flush();
    }
}



• Run this application and click on download button, browser download box appears , open downloaded file and see how your data appears in text file, to export data in a pdf file you have to generate PDF file using some API then you can download it in same way

Cheers:) Happy Learning