Skip to main content

4 Remarkable Notes for JSF Apps Using HTML5


In the previous post, I've already shared with you how my team consults clients by using a HTML prototype. This post is about the used technologies for reusing the provided HTML template and communicating with backend.

What is the issue when using HTML elements with Primefaces components?

Primefaces is a great extension for developing JSF web apps. However, it is really frustrating in case we have to make it work with an existing HTML template. Why?
- Primefaces has its own theme for styling.
- Primefaces changes the HTML structure.
Therefore, that would be a huge effort to use the Primefaces' components to replicate the elements of the HTML template; especially it is impossible for images drawing by "canvas" tag.

That requires us to find a better approach. Since Java EE 7 (introducing JSF 2.2 included), it supports to use HTML5 elements. The idea is that JSF components don't effect the style and HTML structure, so we can easily reuse the provided HTML template. Moreover, we're still able to use Primefaces "No-GUI" components such as "p:ajax", "p:remoteCommand'.

1. JSF Alternatives for HTML5 elements

We can choose to use JSF components, HTML5 elements, or both. Take a look the table "How Facelets Renders HTML5 Elements" of the following link for more detail.
https://docs.oracle.com/javaee/7/tutorial/jsf-facelets009.htm
For example:
<html ... xmlns:jsf="http://xmlns.jcp.org/jsf"
...
    <input type="email" jsf:id="email" name="email"
           value="#{reservationBean.email}" required="required"/>

2. Radio button or How to make a trick for events

There is no JSF component for radio elements. We have to build an alternative by our own. For example:
<div id="gender">
 <div class="control">
  <input type="radio" name="option" checked="true"
   onclick="document.getElementById('gender-hidden-input').setAttribute('value', '0'); onGenderChange();" value="0"></input>
  <label class="control__label" for="optionone">Option One</label>
 </div>
  
 <div class="control">
  <input type="radio" name="option" 
    onclick="document.getElementById('gender-hidden-input').setAttribute('value', '1'); onGenderChange();" value="1"></input>
  <label class="control__label" for="optiontwo">Option Two</label>
 </div>
  
 <h:inputText value="#{data.dataModel.gender}" styleClass="hidden" type="text" id="gender-hidden-input" />
 <p:remoteCommand name="onGenderChange" actionListener="#{logic.onGenderChange}" update="growl"></p:remoteCommand>
</div>

3. Dialog or How to custom Ajax requests

For dialogs/pop-ups, we can use a JQuery library like basicLightbox. We can use "p:remoteCommand" to call ajax  requests to backend. The following is an idea for passing a javascript function as param when executing from different places.
...
okElem.forEach(function (elem) {
 elem.onclick = function (e) {
  
  if(elem.classList.contains("mf-ui-disabled")){
   return false;
  }
  
  var ajaxRequestor = elem.getAttribute('data-ajax-requestor');
  if(ajaxRequestor){
   executeFunction(ajaxRequestor); //ajaxRequestor is a javascript function name which can make by "p:remoteCommand"
  }
  
  instance.close();
  e.preventDefault();
 };
});

...

function executeFunction(functionStr){
 var fn = window[functionStr];
 if (typeof fn === "function") fn();
}

4. Images Exporting

So far, html2Canvas has been the only one library can help us satisfy the requirements of exporting images from client side for all supported browsers including Chrome, Firefox and IE11. Almost other libraries for "html and canvas conversion" won't work with IE due to IE does not support SVG <foreignObject> tag. A fun fact here is this library even has not been released at the time we applied it for our project.
function exportProductChart(){
 
 var productHouse = document.querySelector("#overallPdfExportHouseWrapper");
 
 html2canvas(productHouse, {
   scale: 3,
      onrendered: function(canvas) {
       var productHouseImg = canvas.toDataURL("image/png");
       onClickExportPdfDialogOkBtn = function() {//override the function "onClickExportPdfDialogOkBtn" because this function can be called in another place.
     PrimeFaces.ab({
      s:"onClickExportPdfDialogOkBtn",
      f:"mainForm",
      p:"pdfExportDialog",
      u: "pdfExportDialog",
      onco:function(xhr,status,args){
       $('[id$=downloadPdf]').click();
      },
      pa:[{name: "mfDialogAction", value: "productChartExport"},
          {name: "productChoiceHouse", value: productHouseImg}]
     });
    }
    onClickExportPdfDialogOkBtn(); //p:remote command
    }
 });
}

References:
[1]. http://www.oracle.com/technetwork/articles/java/enterprise-html5-2227136.html
[2]. https://docs.oracle.com/javaee/7/tutorial/jsf-facelets009.htm
[3]. https://github.com/tsayen/dom-to-image

Comments

  1. Chào anh Hương, em là sinh viên mới tiếp cận Java và CNTT nên không biết nhiều. Em đang định dùng lại code mã nguồn mở của SweetHome 3D nhưng mò mẫm mãi vẫn không xem được code của họ. Mong anh chỉ giáo

    ReplyDelete
    Replies
    1. Chào bạn!
      Tôi chưa có kinh nghiệm lập trình với SweeHome 3D, nên tôi sẽ chỉ có thể cho lời khuyên:
      1. Bạn nên làm theo hướng dẫn này Developer Guide. (phải cái bạn nỏi không??)
      2. Bạn xem source code của file jar (Download) bằng java decompiler (vd: JD) hoặc cài plugin decompiler trên Eclipse.

      Không biết bạn đã tham gia cộng đồng này Dạy Nhau Học chưa, nếu chưa thì bạn có thể lên đây đặt câu hỏi và chia sẻ lại với mọi người.

      Delete

Post a Comment

Popular posts from this blog

[Snippet] CSS - Child element overlap parent

I searched from somewhere and found that a lot of people says a basic concept for implementing this feature looks like below: HTML code: <div id="parent">  <div id="child">  </div> </div> And, CSS: #parent{   position: relative;   overflow:hidden; } #child{   position: absolute;   top: -1;   right: -1px; } However, I had a lot of grand-parents in my case and the above code didn't work. Therefore, I needed an alternative. I presumed that my app uses Boostrap and AngularJs, maybe some CSS from them affects mine. I didn't know exactly the problem, but I believed when all CSS is loaded into my browser, I could completely handle it. www.tom-collinson.com I tried to create an example to investigated this problem by Fiddle . Accidentally, I just changed: position: parent; to position: static; for one of parents -> the problem is solved. Look at my code: <div class="modal-body dn-placeholder-parent-position&quo

The HelloWorld example of JSF 2.2 with Myfaces

I just did by myself create a very simple app "HelloWorld" of JSF 2.2 with a concrete implementation Myfaces that we can use it later on for our further JSF trying out. I attached the source code link at the end part. Just follow these steps below: 1. Create a Maven project in Eclipse (Kepler) with a simple Java web application archetype "maven-archetype-webapp". Maven should be the best choice for managing the dependencies , so far. JSF is a web framework that is the reason why I chose the mentioned archetype for my example. 2. Import dependencies for JSF implementation - Myfaces (v2.2.10) into file pom.xml . The following code that is easy to find from  http://mvnrepository.com/  with key words "myfaces". <dependency> <groupId>org.apache.myfaces.core</groupId> <artifactId>myfaces-api</artifactId> <version>2.2.10</version> </dependency> <dependency> <groupId>org.apache.myfaces.core<

Styling Sort Icons Using Font Awesome for Primefaces' Data Table

So far, Primefaces has used image sprites for displaying the sort icons. This leads to a problem if we want to make a different style for these icons; for example, I would make the icon "arrow up" more blurry at the first time the table loading because I want to highlight the icon "arrow down". I found a way that I can replace these icons with Font Awesome icons. We will use "CSS Pseudo-classes" to achieve it. The hardest thing here is that we should handle displaying icons in different cases. There is a case both "arrow up" and "arrow down" showing and other case is only one of these icons is shown. .ui-sortable-column-icon.ui-icon.ui-icon-carat-2-n-s { background-image: none; margin-left: 5px; font-size: 1.1666em; position: relative; } .ui-sortable-column-icon.ui-icon.ui-icon-carat-2-n-s:not(.ui-icon-triangle-1-s)::before { content: "\f106"; font-family: "FontAwesome"; position:

Selenium - Use Explicit Waits for checking elements quickly disappear like loading icon

I have a table that is displayed a list of competence groups. When I click on a competence group, it will display a table that contains a lot of criteria belong to the competence group. Each times I click on a competence group, a "loading" icon is displayed while waiting for all criteria is fully displayed. <div id="loading" style="display: none;"> <div></div> <div></div> I tried to write a Selenium test to make sure this behavior is covered. I saw that the loading icon element is always available on DOM tree because I just used Jquery to handle its displaying. Beside that, the loading icon is appeared dynamically and quickly disappear afterwards. It is hard to checking the visibility on GUI of loading icon. By normal way that I frequently used, the code looks like: public boolean isLoadingIconDisplayed() { List<WebElement> loadingIcons = driver.findElements(By.id("loading")); if(!loadingIcons.isE

How to convert time between timezone in Java, Primefaces?

I use the calendar Primefaces component with timeOnly and timeZone attributes for using only hour format (HH:mm). Like this: <p:calendar id="xabsOvertimeTimeFrom" pattern="HH:mm" timeOnly="true" value="#{data.dateFrom}" timeZone="#{data.timeZone}"/> We can convert the value of #{data.dateFrom} from GMT/UTC time zone to local, conversely, from local time zone to GMT/UTC time zone. Here is my functions: package vn.nvanhuong.timezoneconverter; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; import java.util.TimeZone; public class TimeZoneConverter { /** * convert a date with hour format (HH:mm) from local time zone to UTC time zone */ public static Date convertHourToUTCTimeZone(Date inputDate) throws ParseException { if(inputDate == null){ return null; } Calendar calendar = Calendar.getInstance(); calendar.setTime(inputDate); int