Question

I have a view scoped bean where I create a person. A person can have a picture. This picture is uploaded the same page the person is created. The picture is not stored in a database or on disk (since the person isn’t created yet). The bean has to be view scoped since a person can be created elsewhere and this uses the same bean. If the bean is session scoped and a user uploads a picture but does not save the person, the picture will be displayed next time the user tries to create a person.

I solved this by using two beans; one view scoped bean to create the person and a session scoped bean to upload the picture and to get the picture as a stream. This however causes the problem noted above.

How can I solve this in a better way?

The upload bean:

@ManagedBean(name = "uploadBean")
@SessionScoped
public class UploadBean
{
    private UploadedFile    uploadedFile;

    public UploadedFile getUploadedFile()
    {
        return uploadedFile;
    }

    public StreamedContent getUploadedFileAsStream()
    {
        if (uploadedFile != null)
        {
            return new DefaultStreamedContent(new ByteArrayInputStream(uploadedFile.getContents()));
        }
        return null;
    }

    public void uploadFile(FileUploadEvent event)
    {
        uploadedFile = event.getFile();
    }
}

The create-a-person bean:

@ManagedBean(name = "personBean")
@ViewScoped
public class PersonBean
{
    private Person newPerson = new Person();

    public Person getNewPerson()
    {
        return newPerson;
    }

    private UploadedFile getUploadedPicture()
    {
        FacesContext context = FacesContext.getCurrentInstance();
        ELContext elContext = context.getELContext();
        UploadBean uploadBean = (UploadBean) elContext.getELResolver().getValue(elContext, null, "uploadBean");
        return uploadBean.getUploadedFile();
    }

    public void createPerson()
    {
        UploadedFile uploadedPicture = getUploadedPicture();
        // Create person with picture;
    }
}

The relevant JSF page part:

<h:form enctype="multipart/form-data">
    <p:outputPanel layout="block" id="personPicture">
        <p:graphicImage height="150"
            value="#{uploadBean.uploadedFileAsStream}"
            rendered="#{uploadBean.uploadedFileAsStream != null}" />
    </p:outputPanel>
        <p:fileUpload auto="true" allowTypes="/(\.|\/)(gif|jpe?g|png)$/"
            fileUploadListener="#{uploadBean.uploadedFile}"
            update="personPicture" />
    <p:commandButton value="Save" actionListener="#{personBean.createPerson()}"/>
</h:form>

Answer 1

I’ve gone for a different approach. I initially went for displaying an uploaded image, however if the Person isn’t created yet it seemed like a better idea to keep it all client side. I found this question and created the following based on the chosen answer:

In the head I include html5shiv if the browser is IE and the version is less than 9 for compatibility:

<h:outputText value="&lt;!--[if lt IE 9]&gt;" escape="false" />
<h:outputScript library="js" name="html5shiv.js" />
<h:outputText value="&lt;![endif]--&gt;" escape="false" />

To display/upload the image I have these elements:

<p:fileUpload binding="#{upload}" mode="simple"
    allowTypes="/(\.|\/)(gif|jpe?g|png)$/"
    value="#{personBean.uploadedPicture}"/>
<p:graphicImage value="#" height="150" binding="#{image}" />

And some JavaScript/jQuery magic:

function readPicture(input, output)
{
    if (input.files && input.files[0])
    {
        var reader = new FileReader();
        reader.onload = function(e)
        {
            output.attr('src', e.target.result);
        };
        reader.readAsDataURL(input.files[0]);
    }
}

$("[id='#{upload.clientId}']").change(
    function()
    {
        readPicture(this, $("[id='#{image.clientId}']"));
    });

The uploadedPicture property is now a simple property:

@ManagedBean(name = "personBean")
@ViewScoped
public class PersonBean
{
    private UploadedFile uploadedPicture;

    public UploadedFile getUploadedPicture()
    {
        return uploadedPicture;
    }

    public void setUploadedPicture(UploadedFile uploadedPicture)
    {
        this.uploadedPicture = uploadedPicture;
    }
}