Tech Notes Dairy

Today I have used SVN for the first time and I got mixed feeling about SVN plugin for Eclipse.

Overwall it works ok , however there were couple of things that confused me.

A lot of people claim SVN to be faster, but I really did not feel it. To me it seemed to have no better performance than CVS.

Many times, when integrating other people changes to CVS, I just place updated file over existing and commit. When I tried to do that using eclipse SNV plugin, it marked file as deleted. I needed to open file and use cut-n-paste to replace its content. Seems a little weird to me and CVS is much straightforward in this.

SVN has file locking - this is a good thing, becuase many tims you need to lock a file while working on it and merge really complicate things, rather solves issues. Developers suppose to talk one with each other about changes, but it does not work at times.

My final conclusion that I will need to think if I really want to use SVN instead of CVS.

• In this implementation I specifically using session to store errors and use redirect ="true" attribute in action mapping config.
• Due my laziness, I am using FONT tags instead of CSS, but it does the job just fine.
• Errors then saved on the session, in order to survive http redirect.
• Jsp page has logic for transering error object from session to request scope, removing it afterwards. This is needed to display it only once, and avoid displaying messages upond page refresh after action performed.

Implementation Steps

1. Create SuccessResources.properties
#com.igrapp.uc1_strutserror.SuccessResources.properties
uc1_struts_error.success=This is a success

2. Create ErrorResources.properties
#com.igrapp.uc1_strutserror.ErrorResources.properties
uc1_struts_error.error=This is error

3. Configure SuccessResources.properties and ErrorResources.properties in struts-config.xml
Add entries below to the struts-config.xml
<message-resources parameter="com.igrapp.u1_strutserror.ErrorResources" key="errorBundle" />
<message-resources parameter="com.igrapp.u1_strutserror.SuccessResources" key="successBundle"/>

4. Code action.
DynaActionForm f = (DynaActionForm)form;
ActionMessages msg = new ActionMessages();

String test = f.getString("test");
if ( test == null || test.trim().length() == 0 ) {
msg.add(null, new ActionMessage( "uc1_struts_error.error"));
} else {
msg.add(null, new ActionMessage( "uc1_struts_error.success"));

}

saveErrors(req.getSession(), msg);
return mapping.findForward("success");

4. Add action and DynaForm into struts-config.xml
...
<form-bean name="MyForm"
type="org.apache.struts.action.DynaActionForm">
<form-property name="test" type="java.lang.String"/>
</form-bean>
...
<action
path="/testaction"
type="com.igrapp.u1_strutserror.MyAction"
name="MyForm"
scope="request"
validate="false"
>
<forward
name="success"
path="/index.jsp"
redirect="true"
/>
</action>
....

5. Add code to jsp page.
<%
Object o = session.getAttribute( "org.apache.struts.action.ERROR");
if ( o != null ) {
request.setAttribute( "org.apache.struts.action.ERROR", o);
session.removeAttribute( "org.apache.struts.action.ERROR");
}
%>
...


<font color="red"><html:errors bundle="errorBundle"/></font>
<font color="green"><html:errors bundle="successBundle" />
...


Download source archive from my personal web site at http://www.igorgrapp.com/files/struts_error_message.zip

# posted by Igor Grapp @ 11:34 PM 0 comments