ImageReplacerFieldGroup

/**
 * Showcasing a custom FieldGroupGieldFactory that generates an UploadField(from https://vaadin.com/directory#addon/easyuploads)
 * if the FieldGroup is trying to bind to a byte[] object property.
 * The image instance is updated each time a new image is uploaded
 *
 * Ruiu Gabriel Mihai (gabriel.ruiu@mail.com)
 */
public class ImageReplacerFieldGroup extends FormLayout {

    public ImageReplacerFieldGroup() {

        final ImagePojo imagePojo = new ImagePojo();
        imagePojo.setName("superman");
        imagePojo.setImageContent(new byte[0]);

        BeanItem<ImagePojo> item = new BeanItem<ImagePojo>(imagePojo);


        final StreamResource imageResource = new StreamResource(new StreamResource.StreamSource() {
            @Override
            public InputStream getStream() {
                return new ByteArrayInputStream(imagePojo.getImageContent());
            }
        }, "myimage");
        imageResource.setCacheTime(0);

        final Image image = new Image("Image", imageResource);
        addComponent(image);


        FieldGroup fieldGroup = new FieldGroup(item);
        fieldGroup.setFieldFactory(new ImageEnhancedFieldFactory(new Property.ValueChangeListener() {
            @Override
            public void valueChange(Property.ValueChangeEvent event) {
                SimpleDateFormat df = new SimpleDateFormat("yyyyMMddHHmmssSSS");
                String filename = "myfilename-" + df.format(new Date()) + ".jpg";
                imagePojo.setImageContent((byte[])event.getProperty().getValue());
                image.markAsDirty();
                imageResource.setFilename(filename);
            }
        }));

        addComponent(fieldGroup.buildAndBind("Image name", "name"));
        addComponent(fieldGroup.buildAndBind("Image content", "imageContent"));
    }

    private class ImageEnhancedFieldFactory extends DefaultFieldGroupFieldFactory {

        private Property.ValueChangeListener fileUploadedListener;

        private ImageEnhancedFieldFactory(Property.ValueChangeListener fileUploadedListener) {
            this.fileUploadedListener = fileUploadedListener;
        }

        @Override
        public <T extends Field> T createField(Class<?> type, Class<T> fieldType) {
            if (byte[].class.equals(type)) {
                UploadField uploadField = new UploadField(UploadField.StorageMode.MEMORY);
                uploadField.setFieldType(UploadField.FieldType.BYTE_ARRAY);
                uploadField.setButtonCaption("Change image");
                uploadField.addListener(fileUploadedListener);
                return (T) uploadField;
            }
            return super.createField(type, fieldType);
        }
    }
}