GridFileDownloader

FileDownloader for Grid

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An extension that either adds a new download column to Grid or uses a specified column for the task.

See the ReadMe for a list of known issues.

Note: push or polling required!

Update: check out new GridActionRenderer add-on's DownloadActionGrid for a simplified use case that supports column reordering out of the box.

Sample code

 /**
     * Adds a GridFileDownloader extension that adds a download column to the
     * Grid since no existing propertyId is specified.
     *
     * @param grid
     */
    private void addGridFileDownloader(Grid grid) {
        new GridFileDownloader(grid,
                new GridFileDownloader.GridStreamResource() {

                    @Override
                    public InputStream getStream() {
                        byte[] data = downloadPojo.getData();
                        if (data == null) {
                            return new ByteArrayInputStream(new byte[0]);
                        }
                        return new ByteArrayInputStream(data);
                    }

                    @Override
                    public String getFilename() {
                        return downloadPojo.getName();
                    }

                }) {

            @Override
            protected void setRowId(Object rowId) {
                try {
                    downloadPojo = (DownloadPojo) rowId;
                    super.setRowId(rowId);
                } catch (ClassCastException e) {
                    throw new IllegalArgumentException(
                            "RowId must be DownloadPojo", e);
                }
            }
        };
    }

package org.vaadin.anna.gridactionrenderer.demo;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import org.vaadin.anna.gridactionrenderer.DownloadActionGrid;
import org.vaadin.anna.gridactionrenderer.GridAction;
import org.vaadin.anna.gridactionrenderer.GridActionRenderer.GridActionClickEvent;
import org.vaadin.anna.gridactionrenderer.GridDownloadAction;
import org.vaadin.gridfiledownloader.GridFileDownloader.GridStreamResource;

import com.vaadin.data.Item;
import com.vaadin.server.FontAwesome;
import com.vaadin.ui.Notification;
import com.vaadin.ui.Notification.Type;

public class MyDownloadActionGrid extends DownloadActionGrid {

    @SuppressWarnings("unchecked")
    public MyDownloadActionGrid() {
        super(createActions());

        addStyleName("demogrid");
        addColumn("name");
        setCaption("Download Action Grid");

        Column column = addColumn("actions");
        column.setRenderer(getGridActionRenderer());

        for (int i = 0; i < 25; ++i) {
            Item item = getContainerDataSource().addItem(i);
            item.getItemProperty("name").setValue("Item" + i);
            item.getItemProperty("actions").setValue(i % 3 == 0 ? "1,2" : "-1");
        }
    }

    private static List<GridAction> createActions() {
        List<GridAction> actions = new ArrayList<GridAction>();
        actions.add(new GridAction(FontAwesome.USER, "user"));
        actions.add(new GridAction(FontAwesome.GEAR, "settings"));
        actions.add(new GridDownloadAction(FontAwesome.DOWNLOAD, "download"));
        return actions;
    }

    @Override
    public void click(GridActionClickEvent event) {
        super.click(event); // must be called

        if (event.getAction().isDownloadAction()) {
            return; // already handled in extended method
        }
        Item item = getContainerDataSource().getItem(event.getItemId());
        Notification.show(item.getItemProperty("name").getValue() + " - "
                + event.getAction().getDescription(), Type.ERROR_MESSAGE);
    }

    @Override
    public GridStreamResource createStreamResource() {
        return new GridStreamResource() {

            @Override
            public InputStream getStream() {
                // in real use-case you would find or create the file here based
                // on the downloadItemId and action (if there are more than one)
                int writeAtOnce = 1024 * 1024 * 1024;
                byte[] b = new byte[writeAtOnce];
                return new ByteArrayInputStream(b);
            }

            @Override
            public String getFilename() {
                // in real use-case you would find or create the file here based
                // on the downloadItemId and action (if there are more than one)
                GridDownloadAction downloadAction = getDownloadAction();
                Item item = getContainerDataSource().getItem(
                        getDownloadItemId());

                return "file_" + downloadAction.getDescription() + "_"
                        + item.getItemProperty("name").getValue() + ".txt";
            }
        };
    }

}

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