Question

I have the next code to load a set of images whose streams are in a datamodel called names. My problem is when I declare the var inside the p:datatable tag seems like has nothing. Any idea? thx!

<p:dataTable value="#{controlador.names}"  var="nombre" rendered="true">
                <p:column rendered="true">
                    <h:outputText value="#{nombre.stream}"/>
                    <p:graphicImage value="#{nombre.stream}"/>
                </p:column>
            </p:dataTable>

Answer 1

The p:graphicImage uses another request so you need to pass an identifier to the managedBean like this.

<p:dataTable value="#{productManaged.products}" var="productIterated">
     <p:column>
          <f:facet name="header">
               <h:outputText value="#{product.pic}"/>
          </f:facet>
          <p:graphicImage value="#{productManaged.dynamicProductImage}">
               <f:param name="product_id" value="#{productIterated.id}"/>
          </p:graphicImage>
     </p:column>
</p:dataTable>

Another thing that you should take care is to return something in the StreamedContent or is gonna fail. Do something like this:

public StreamedContent getDynamicProductImage() {
       String id = FacesContext.getCurrentInstance()
                       .getExternalContext().getRequestParameterMap().get("product_id");
       if(id!=null && this.products!=null && !this.products.isEmpty()){
           Integer productId = Integer.parseInt(id);
           for(Product productTemp:this.products){
               if(productTemp.getId().equals(productId)){
                   return new DefaultStreamedContent(
                        new ByteArrayInputStream(productTemp.getImage()),                            
                             productTemp.getMimeType());
               }
           }
       }
       return new DefaultStreamedContent(
                        new ByteArrayInputStream(this.products.get(0).getImage()), 
                             this.products.get(0).getMimeType()); //if you return null here then it won t work!!! You have to return something.
}

or you can read this thread http://primefaces.prime.com.tr/forum/viewtopic.php?f=3&t=4163

Answer 2

After wasting hours of going the the process of implementing the many solutions I found for this issue (i.e. including a param or attribute), The only solution I managed to find that actually works can be found here: Serving Dynamic Content with PrettyFaces

Answer 3

Remove the <h:outputText>. You can read a stream only once. It cannot be re-read another time.

As to the p:graphicImage part, you need to feed it with a value of DefaultStreamedContent. Also see this blog entry.

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