Hi James, Thanks for the quick response. Thanks for helping out. I will try to proceed with that information. Next time I will use Jira for communication specific to the task.
Regards, Dumindu. Dumindu Buddhika, Undergraduate, Department of Computer Science and Engineering, University of Moratuwa, Sri Lanka. Mobile:+94715764749 On Sat, Mar 7, 2015 at 7:59 AM, James Taylor <jamestay...@apache.org> wrote: > Hi Dumindu, > > Good questions. For future, best to post questions specific to your > JIRA on the JIRA itself. All JIRA comments appear in the dev list as > well. > > For the @BuiltInFunction annotation, you'd define your second type as > PVarbinary, since the element being appended may be of any type. To > get the actual type at runtime, you'd use the getChildren() method > which returns a List<Expression>. The children represent the arguments > to your built-in function. In your case, getChildren().get(0) > expression would represent the array, while the getChildren().get(1) > expression would represent the element being appended. From the > expression, you can call getDataType() to get the actual PDataType at > runtime, and use the dataType.toBytes() method to get the bytes that > represent the actual value which you can add to the array. Take a look > at PArrayDataType for methods that manipulate the array. If possible, > you'd want to keep the array as byte[], as converting back and forth > to objects is expensive. You might need to add a new method to > PArrayDataType that allows the byte[] of an element to be appended to > the byte[] of the array. > > Note that you know the data types at compile time, so it's possible > that you could create a different expression for the > ArrayAppendFunction from a custom factory method. An example of this > is with the RoundFunction - it has a nodeClass attribute in its > annotation that delegate the creation to the indicated class. If you > look at that class, you'll see that it ends up creating a > RoundDateExpression, RoundTimestampExpression, or > RoundDecimalExpression depending on the type of the argument. In this > case, I don't think it's worth going this route, though. > > HTH. Thanks, > > James > > On Fri, Mar 6, 2015 at 5:16 PM, Dumindu Buddhika > <dumindukarunathil...@gmail.com> wrote: > > Hi all, > > > > I am a GSOC aspirant this year from Department of Computer Science and > > Engineering, University of Moratuwa, Sri Lanka. > > > > I would like to work on PHOENIX-1665, to create missing array built-in > > functions. I am currently trying to implement ARRAY_APPEND function. I > have > > some questions associated with this. It would be great if someone can > > answer. > > PBinaryArray type would be first input of this function. Second would be > a > > primitive type element to be appended to the first given array. So I am > > guessing it should be PDataType. > > > > The approach I thought was using PDataType's toObject method to > construct > > a PhoenixArray from given bytes(from ptr) and add the new element to it > > then convert it back to bytes. > > > > When using this approach I have a problem how to convert the second input > > argument(the element to be appended to the array) to corresponding > object. > > if the type of this is known of this input for sure it can be done( ex: > if > > its PInteger then PInteger.INSTANCE.getCodec().decodeInt can be used). > But > > here it can be any of the primitive types to my understanding. so how to > > convert to the corresponding datatype object without exactly knowing the > > type? > > > > It would be really great if someone can help me on this. if this approach > > is wrong or if there is a better approach(directly manipulating bytes) I > > would also like to know :) > > > > Thank you. > > > > Regards, > > Dumindu. >
