将参数从Java传递给Tapestry中的js

Question

I use Apache Tapestry as web application framework.

I have variable in my java code. I need value of this variable in javascript after page loaded.

For example java class:

@Import(library = "RoomManagement.js")
public final class RoomManagement{
  @Property
  private long contactId;
}

and js in RoomManagement.js:

window.onload = function(){
    alert(contactId);
}

How can I pass it directly to javascript?

I can not pass value to js like to template, cause it is .js file not .tml.

I can add invisible tag to my page, write value to this tag and read it from js. But do you know another way?

Answer 1

You will need to use the JavaScriptSupport service.

Your java file:

@Import(library = "RoomManagement.js")
public final class RoomManagement{

  @Inject
  private JavaScriptSupport javascriptSupport;

  @Property
  private long contactId;

  @AfterRender
  private void setup() {
    JSONObject jsonObject = new JSONObject();
    jsonObject.put("contactId", contactId);
    javascriptSupport.addInitializerCall("RoomManagement",jsonObject);
  }
}

Your RoomManagement.js

Tapestry.Initializer.RoomManagement = function (parameters) {
    //do whatever you need here
    alert('Your contactId: ' + parameters.contactId);
};