Proper DSResponse for an empty fetch?

[stonebranch1]

I was wondering what the proper DSResponse should be when an empty fetch is performed?

I set the startRow, endRow and totalRows all to 0.

What should be set for the Data via the setData api?

Do I set anything, or null, or an empty List say via Collections.EMPTY_LIST?

Thanks.

[Isomorphic]

An empty List would be the most correct, all 3 possibilities you list are correctly handled.

[stonebranch1]

Thanks, I am currently setting it to an empty list. I just wanted to make sure I was setting it properly in order to avoid any potential problems.

[stonebranch1]

I have just update our ds.xml to add an includeFrom field and reference it as the displayField via:

<field name="calendarName" includeFrom="calendar.name"/> 
<field name="calendar" foreignKey="calendar.id" displayField="calendarName" type="text"/>

The calendar name gets fetched ok when I have records but when I have no records to return for the list I get the following exception when I use an empy list:

2014-05-16-13:50:20:661 -0400   WARN [http-bio-8080-exec-8] dsRequest.execute() failed: 
java.lang.IndexOutOfBoundsException: Index: 0
	at java.util.Collections$EmptyList.get(Collections.java:3212)
	at com.isomorphic.datasource.DSRequest.applyManualFilterAndSort(DSRequest.java:5311)
	at com.isomorphic.datasource.DSRequest.execute(DSRequest.java:2567)
	at com.isomorphic.servlet.IDACall.handleDSRequest(IDACall.java:215)

and if set the data to null instead I get this exception:

2014-05-16-13:54:09:856 -0400   WARN [http-bio-8080-exec-4] dsRequest.execute() failed: 
java.lang.NullPointerException
	at com.isomorphic.datasource.DSRequest.applyRelatedDSRequest(DSRequest.java:5040)
	at com.isomorphic.datasource.DSRequest.fetchRelatedValues(DSRequest.java:4929)
	at com.isomorphic.datasource.DSRequest.execute(DSRequest.java:2566)
	at com.isomorphic.servlet.IDACall.handleDSRequest(IDACall.java:215)

Anything I should try?

Thanks

Code Level: SmartClient Version: v9.1p_2014-05-15/Pro Deployment (built 2014-05-15)

Using custom data source implementation.

[Isomorphic]

Sigh. The code already handles the result of get(0) returning null, but of course since this is Java, an exception is thrown instead. We'll revise this.

Just a note that, since what you're doing here is effectively requesting the equivalent of a SQL JOIN across two different DataSource types where no native SQL is possible, the server framework is doing the equivalent of a SQL join in memory in Java.

This is not fast. Just wanted to make sure you're aware.

[stonebranch1]

Good point about the SQL Join.

I think I can do the join myself and then I can make the subsequent call to fetchRelatedValues bascially avoid the extra lookup since I will have the displayName. I am pretty sure I can make that work for me.

Thanks for pointing that out.

[Isomorphic]

You can find this problem fixed in next nightly build.

[stonebranch1]

Thanks works fine now.