New features in DWR 0.8

DWR version 0.8 contains a big list of new features. You can download version 0.8 from The change log looks like this:

  • Batch sending of remote calls:
    DWR will now send a group of remote calls together in a single batch to reduce network latency. See DWREngine.beginBatch() and DWREngine.endBatch() for more information.
  • Provision of call ordering promises:
    DWR can return results in the order in which they were sent using DWREngine.setOrdered(). Warning: Setting this to true will slow down your application, and it expose you to timeouts if a message gets lost. In addition and it may well mean that you are being lazy and not thinking about the asynchronous model properly.
  • Fine grained access control:
    You can now specify exactly which methods are allowed and disallowed using the include and exclude elements in dwr.xml:
    <create creator="new" javascript="JDate" class="java.util.Date">
      <include method="getSeconds"/>
      <include method="getMinutes"/>
    The alternative is to <exclude .../>. You can do one or the other but not both.
  • J2EE role based authorization:
    You can now specify that certain methods are only available to users with certain roles:
    <create creator="new" javascript="JDate" class="java.util.Date">
      <auth method="toString" role="devel"/>
    This requires you to have added J2EE security turned on in your web.xml.
  • Methods on java.lang.Object (like wait()) are now disallowed.
  • Enhanced debug pages:
    The debug pages at http://localhost:8080/[YOUR-WEB-APP]/dwr have been enhanced to allow you to enter parameters other than strings, to show more detail on returned objects and to give more feedback on why methods are unavailable.
  • Auto-fill of Servlet Spec parameters:
    If you have a DWR remoted method that has an HttpServletRequest parameter then DWR will automatically fill it in for you. This gives you a way of accessing HttpServletRequest like ExecutionContext except that you don't get the dependency on DWR. It also works for HttpServletResponse etc.
  • Logging is now fine grained, and there is more of it:
    If you were turning DWR debug on globally, you probably don't want to any more!
  • You can specify detailed type information for collections:
    List, Set etc don't have type info (and even under 1.5 it seems you can't get at it) so you can specify the types in dwr.xml:
    <create creator="new" javascript="Test" class="">
      <parameter method="testBeanSetParam" number="0" type=""/>
    This solution is not perfect, and there is an update planned post 1.0

We are working on a smaller list for the next version so we are not that far from 1.0.

Update: Make that 0.8.1; there was an annoying Javascript error as a result of me fixing some issues brought up by a Javascript lint program. That'll teach me to use lint.


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