jQuery datepicker range : Select date with From and To.

    jQuery datepicker is one the sophisticated ui components jQuery provides. There are loads of options to customize the datepicker as per your needs. Generally it's used on a text field, which when clicked opens an interactive calendar. User selects a date and input field gets filled with the date in appropriate date format as per our configuration. 

  There are many uses of this kind of datepicker. One of them is to select a range of dates with structure like select date From and select date To. Just the way shown below :

Datepicker range

   

     Creating this kind of range datepickers in jQuery is very easy. You need to use onSelect callback function along with minDate and maxDate. The idea is that when user selects "from" date, the selected date is set as minDate for "to" datepicker. And when user selects "to" date, the selected date is set as maxDate for "from" datepicker. This enables user to select a date in appropriate range only and you need not to perform any range validation like say "to" is not older than "from". 

    Consider "from" and "to" are ids of from and to datepicker's text fields. I believe you have included js files for jQuery and jQuery UI along with css file of UI. The code snippet looks like this : 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

$( "#from" ).datepicker({ changeMonth: true, changeYear:true, maxDate:0, onSelect: function( selectedDate ) { $( "#to" ).datepicker( "option", "minDate", selectedDate ); } }); $( "#to" ).datepicker({ changeMonth: true, changeYear:true, maxDate:0, onSelect: function( selectedDate ) { $( "#from" ).datepicker( "option", "maxDate", selectedDate ); } });

    Please take note of how onSelect function is used and how minDate and maxDate are set. 

    Setting maxDate to 0 (today) is used to prevent user from selecting date larger than today's date, this is used mainly because range datepickers are generally used to select date from past like selecting range for showing history logs, college years etc. You can use or remove that as per your needs.

   This fiddle shows how it works : 

ForwardAction and IncludeAction in struts

   The org.apache.struts.actions.ForwardAction class enables you to forward request to the specified URL without going through Controller. ForwardAction is an utility class  used in cases where a user simply needs to forward the control to another JSP . Doing this directly violates the MVC principles.  So they have given this option for  action-mapping. Note that we do not  create any action class here. With ForwardAction , simply create an action mapping  in the Struts configuration file  and specify the location where the action should forward the request with the help of "parameter" attribute of action tag.
For example:

In JSP :

<html:link page="/Welcome.do">
           Click here
</html:link> 

In strus-config :

<action-mappings>
<action
  path="/Welcome"
  type="org.apache.struts.actions.ForwardAction"
  parameter="/Welcome.jsp"/>
</action-mappings> 

there is shortcut for above configuration. you can achieve same simply by:

<action path="/Welcome" include="/Welcome.jsp"/>

org.apache.struts.actions.IncludeAction is somewhat like ForwardAction but the resulting resource is included in the HTTP response instead of forwarding the request to. Actually this is of not much use. Its mainly used to integrate old/legacy applications with Struts transparently. More like integrating simple servlet into struts application. 

In Struts-config file:

<action path="/hello" parameter="/helloServlet"   type="org.apache.struts.actions.IncludeAction"> 
</action>

Jsp:

<jsp:include page="/hello.do"></jsp:include>

The parameter attribute indicates the actual resource that has to be included in the response. As mentioned earlier, the use of IncludeAction is limited to including responses from existing Servlet in the current page. This requires the use of <jsp:include> in the jsp page.

DynaActionForm in struts with example.

      If you are writing Struts application, you are expected to write a FormBean for every page. But it's too tedious to write lot's of FormBeans with just getters and setters for the fields.
      You can avoid this by using DynaActionForm (Dynamic Form Beans) which are an extension of FormBeans that allow you to specify their fields inside the Struts configuration file itself instead creating concrete classes with getters and setters.
    For using this, you need to configure the form bean of DynaActionForm inside strust-config file. Do it this way :

<form-bean name="dynamicLoginForm" 
           type="org.apache.struts.action.DynaActionForm">
           <form-property name="userName" 
                          type="java.lang.String" 
                          initial="nils"></form-property>
           <form-property name="password" 
                          type="java.lang.String"></form-property>
</form-bean>

"name" attributes of "form-property" specify the field names and "type" specify the type of the field. you also can specify the initial value by "initial" attribute. And use dynamicLoginForm(name) of this form bean as value for name attribute of corresponding action just like normal FormBeans .

<action path="/login" 
            name="dynamicLoginForm">
</action>

    Now the values of fields of corresponding form on the webpage will be populated to the form which will be dynamically created. 
   So you need a way to access this values in Action class's execute() method. For that you need to use get() or getXXX() methods of DynaActionForm.
    Following snippet shows the way to access fields of DynaActionForm in execute() method of Action :

public ActionForward execute(ActionMapping mapping, 
                             ActionForm form,
                             HttpServletRequest request, 
                             HttpServletResponse response)
                      throws Exception {


     DynaActionForm theForm = (DynaActionForm)form;
     String userName = theForm.getString("userName");
     String password = (String)theForm.get("password");


}

Well, DynaActionForm is this much simple :)

What is resource bundle in struts and using multiple resource bundle files.

      Resource bundles allow Java applications to be easily internationalized by having application content placed into bundles. This content can then be read by the application at run time. Therefore, instead of having content hardcoded in the application, the application reads its content from the bundle. Struts has built-in support for working with Java's resource bundle mechanism. 

      Resource bundle resources can be accessed from JSPs to populate them with content. Resource bundle properties files simply contain key/value pairs. The resources are accessed by their key. The standard name for the resources bundle properties file in struts is MessageResources.properties. 

   Thes files may contain key/values like this login.empty=Empty username and passwordtitle=Struts Relearn

   
      These files are configured in struts-config.xml :

1 2	<message-resources parameter="com.nils.resources.MessageResources"> </message-resources>

keep in mind that the parameter attribute is a file name without .properties extension.You can access these values in JPSs like this 

1	<bean:message key="title" />

given that bean taglib is configured in the JSP.

     If you want to use multiple properties files with different values for the keys. Then  you just need to specify "key" attribute of message-resources in struts-config.xml entries.

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<message-resources parameter="com.nilesh.resources.MessageResources" key="NormalCase"> </message-resources> <message-resources parameter="com.nilesh.resources.AnotherMessageResources" key="UpperCase"> </message-resources>

        And while using them in JSP use "bundle" attribute of bean:message.

1 2	<bean:message key="title" bundle="NormalCase"/> <bean:message key="title" bundle="UpperCase"/>

bundle attribute is mapped to key attribute of message-resources which specifies the properties file. 

        If you configure multiple message-resources and don't specify the keys for them both of them will have default key 

"org.apache.struts.action.MESSAGE"

so when they are used in JSP it will see two files configured with same key and will throw excpetion, this is the same exception you may see when message-resources is misconfigured:

SRVE0068E: Uncaught exception created in one of the service 
methods of the servlet /index.jsp in application StrutsEar. 
Exception created :
com.ibm.websphere.servlet.error.ServletErrorReport:
javax.servlet.jsp.JspException: Cannot find message resources under key 
org.apache.struts.action.MESSAGE.

How to use offline Google maps on android phone in India.

Recently Google launched offline google maps for android phones in India. This new feature allows you to store map of some area on your phone for later use. Say you are going to some new or remote area and not sure if GPS is available there or not, or your network provider provides network there or not, or say you don't use internet on your phone always and you need map under such circumstances then it's better to download map of required area in advance.

No doubt this feature is of great use. This service was available in US and many European countries and now it's made available in India too.

Below are simple steps to get offline google map on your android phone.

1. Have Proper version of Google maps app :

First of all you need to upgrade your google map app if it's older one. Now latest version available is 6.14.1 minimum, minimum  because this is what I upgraded to in 2012 october. You can check if you need to upgrade or not by Google map » Options » more » make offline available, if this option is available then you don't need to upgrade otherwise you need to. And important point to note - this feature is available on android version 2.2+, thank god I am just on edge. 

To upgrade this app goto google play store on your phone search for google map and upgrade if you need.

 
2.Make map available offline :

Once proper version of google map is available, open google maps application search for area whose map you want to be available offline on your android.

by using  options » search.

Once proper area's map is loaded select

options » more options » make available offline.

 
3.  Select Proper Area :

Now it will show rectangular area over the map to chose the area of the map to  download. screen should be showing size of the map of area you have selected in mb along with "select" button which would be disabled. Now pinch in and out over rectangular selection area to select area to download. Keep an eye on select button and size of the map. You can download a map only when select button is enabled. Generally minimum area of the map that you can download is  near about 67mb. keep trying to select size of rectangle so that select button is enabled. try keeping size of the map across 60 to 100 mb.

 4. Download map :
 
Once select button is available, click it and  your map will start downloading. 

wait till map is downloaded. Once it`s downloaded you are ready to use the map offline.

5.  Use offline Google map :

To use offline map, goto options » my places » OFFLINE tab there your offline map will be available. Select it and there you go with your offline map.

don't you worry about phone memory consumption this map doesn't get downloaded completely to your phone memory. I am not sure where exactly this offline map gets downloaded  on phone  but it doesn't  consume your phone memory. I am sure about this because my phone never has that much free phone memory. So cheers. 




6. Enjoy offline maps on your android.