将图像从JSF bean传递到Applet

Question

I meant to post this as a comment at this question but I don't have enough rep and I saw no other way but to ask a new question (although it seems a bit redundant).

Anyway, I tried the solution skuntsel wrote, but backwards: I encoded the image and sent it from the bean to a javascript method (I'm using icefaces so I called it like this JavascriptContext.addJavascriptCall(FacesContext.getCurrentInstance(), functionCall) ). I get the encoded string in the Applet just fine, but when I try to decode it, nothing happens, the code following it is unreachable.

Am I missing something? Thanks in advance!

EDIT: Here's the code I'm using.

In the bean: (method triggered by a button click)

BufferedImage originalImage = acquireImage();
byte[] imageInByte = null;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try {
      ImageIO.write( originalImage, "png", baos );
      baos.flush();
      imageInByte = baos.toByteArray();
      baos.close();
} catch (IOException e) {
    e.printStackTrace();
   }

String imageAsString = Base64.encodeBase64String(imageInByte);
JavascriptContext.addJavascriptCall(FacesContext.getCurrentInstance(), functionCall);

In Javascript:

function getEncodedImage(image){
      var applet = document.getElementById("Applet");
      applet.decodeImage(image);
}

In the applet:

public void decodeImage(String image) {
    System.out.println(image); //works
    byte[] imageByteArray = Base64.decodeBase64(image);
    System.out.println("something"); //doesn't print anything   
    InputStream is = new ByteArrayInputStream(imageByteArray);

    try {
        BufferedImage img = ImageIO.read(is);
        ImageIO.write(img, "png", new File("D:/image.png"));
            is.close();
    } catch (IOException e) {
        e.printStackTrace();
           }

}

Answer 1

The only suspicious part is JavascriptContext.addJavascriptCall(FacesContext.getCurrentInstance(), functionCall); : I don't see any functionCall definition. Despite, replace functionCall by "getEncodedImage(" + image + ")" and it should work.

I haven't worked with ICEfaces to say anything new about how JavascriptContext#addJavascriptCall() works, but there is a standard JSF solution: have a hidden input that contains the encoded string set in an action method and add a JS callback via AJAX.

Namely, the bean part:

private String imageAsString;//getter + setter
public void encodeImage() {
    ...
    this.imageAsString = Base64.encodeBase64String(imageInByte);
}

And the view:

<script>
    function update(data){
        if(data.status == "success") {
            var applet = document.getElementById("Applet");
            var image = document.getElementById("form:image").value;
            applet.decodeImage(image);
        }
    }
</script>
...
<h:form id="form">
    ...
    <h:inputHidden id="image" value="#{bean.imageAsString}" />
    <h:commandButton value="Submit" action="#{bean.encodeImage}">
        <f:ajax render="image" onevent="update" />
    </h:commandButton>
</h:form>