Encoder with

[Athneria, Mahendra]

Hi,

I have one Page which is displaying details of some Client. I am using t:loop 
to display some data. In t: loop I am just passing source and value. So far so 
good, my page is working fine. But when I try to submit the Page it suddenly 
give me the Exception.

"Could not find a coercion from type java.lang.String to type 
[addressUsageValue] Available coercions:.........."

Below is the sample code

<t:loop source="addressUsageInfo" value="addressUsageValue">
                  <tr>
                              <td>${addressUsageValue?.usage}</td>
                              <td>${addressUsageValue?.address}</td>
                              <td>${addressUsageValue?.postCode}</td>
                              <td>${addressUsageValue?.city}</td>
                              <td>${addressUsageValue?.country}</td>
                  </tr>
</t:loop>

I did some goggling and find below references.

http://tapestry.apache.org/5.3.3/apidocs/org/apache/tapestry5/corelib/components/Loop.html
https://issues.apache.org/jira/browse/TAP5-609

So I have created encoder for Loop. Below is the sample code. In below 
toClient() method I have randomly returned any value and in toValue() method I 
am returning null.

      private final ValueEncoder<DtoAddressUsageInfo> addressUssageEncoder = 
new ValueEncoder<DtoAddressUsageInfo>() {

            public String toClient(DtoAddressUsageInfo value) {
                  return String.valueOf(value.getUsage());
            }

            public DtoAddressUsageInfo toValue(String clientValue) {
                  return null;
            }

      };
Now my code is working fine and I am able to submit the form.

Here my doubt comes

First - I am not able to understand why encoder is required when using loop?? 
And if it is required to submit the form then why it is not Mandatory 
parameter??

Second - I have just implemented the Encoder without any logic. I am not able 
to understand where toValue() and toClient() method is used and what is the 
purpose?

Third - when I submit the Page why form required Encoder??

Regards,
Mahendra Athneria
[cid:221044411@01072011-28AB]
Ext-+91 22 6733 3729
Mob-+91 9833 121 309
mahendra.athne...@atos.net
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