messages(field)

html:message/html:error

The messages for specific element could be displayed next to an input element. The annotation would simply denote the id of the element, as shown below.

	<tr>
		<th class="rightLabel">
			<label for="categoryName">Category Name</label>
					<font color="red">*</font></th>
		<td align="left">
			<input type="text" name="categoryName" value="">
		</td>
		<td><!-- aws:element type="messages" id="categoryName" -->
				Category Name is required.<!-- /aws:element --></td>
	</tr>
  

        <html:messages property="categoryName"/>
        <html:errors property="categoryName"/>
        

messages

html:messages/html:errors

This messages element captures the various way platforms would provide text messages for display on the page view.

The representation in the content source is with annotations.

        <!-- aws:element type="messages" value="error" -->
        	<!-- mock presentation could be included here -->
        <!-- /aws:element -->
        

Within the annotations would be the mock representation of the messages. The value would be as recognized on the platform. For example, this could error, info, warning, debug, etc.

The position of the representation outside a form, would dictate that the message is for the page, whereas within a form, it is for the specific form.

The provision of an id attribute would indicate that the messages are for the input element of the specified id.

There are two options for implementation on the platform. One way is to replace the error specification segment, like the one shown in the listing above, with the error tag, shown below.

<html:error/>

This would render the errors corresponding to the form or page, formatted in a standard manner. This standard format is customizable with entries in the message resources file.

NOTE: The Struts Validator Framework, provide standard formatting and error messages, controlled by the messages resource files. This allows standard formatting out of the box, with possibilities of customizations using the resource entries. Some of the applicable entries are shown in the listing below.

        # -- standard error listing format --
        errors.header=<UL>
        errors.prefix=<LI>
        errors.suffix=</LI>
        errors.footer=</UL>
        # -- standard validator? errors--
        errors.invalid={0} is invalid.
        errors.maxlength={0} can not be greater than {1} characters.
        

        # -- validator --
        errors.required={0} is required.
        

????? {0} is required 

This could be combined with the caption, Category Name, for example, to result into the following.

Category Name is required

In effect, the positional variable {0} is replaced by the caption for the field that failed the validation test.

There are no means to explicitly define the caption for a field within Struts; this caption must be included validation declarations (validation.xml entries) that the element is involved with. Some implementation entries would be used to illustrate this later.

Another way to implement this is through the message tag.

<html:messages >

	<logic:messagesPresent>
	   <bean:message key="errors.header"/>
	   <ul>
	   <html:messages id="error">
		  <li><bean:write name="error"/></li>
	   </html:messages>
	   </ul><hr>
	</logic:messagesPresent>