We'd be happy to commit a patch contributing a DoubleType.
On Sun, Mar 13, 2011 at 7:36 PM, Paul Teasdale <teasda...@gmail.com> wrote:
> I am quite new to Cassandra and am trying to model a simple Column Family
> which uses Doubles as column names:
> Datalines: { // ColumnFamilly
> dataline-1:{ // row key
> 23.5: 'someValue',
> 23.6: 'someValue',
> ...
> 4334.99: 'someValue'
> },
> dataline-2:{
> 10.5: 'someValue',
> 12.6: 'someValue',
> ...
> 23334.99: 'someValue'
> },
> ...
> dataline-n:{
> 10.5: 'someValue',
> 12.6: 'someValue',
> ...
> 23334.99: 'someValue'
> }
> }
> In declaring this column family, I need to specify a 'CompareWith' attribute
> for a Double type, but the only available values I found for this attribute
> are:
> * BytesType
> * AsciiType
> * UTF8Type
> * LongType
> * LexicalUUIDType
> * TimeUUIDType
> Is there any support anywere for double values (there has to be something)?
> And if not, does this mean we need to extend
> org.apache.cassandra.db.marshal.AbstractType<Double>?
> package com.mycom.types;
> class DoubleType extends
> org.apache.cassandra.db.marshal.AbstractType<Double> {
> public int compare(ByteBuffer o1, ByteBuffer o2){
> // trivial implementation
> Double d1 = o1.getDouble(0);
> Double d2 = o2.getDoube(0);
> return d1.compareTo(d2);
> }
> //...
> }
> And declare the column family:
> <ColumnFamily CompareWith="<com.mycom.types.DoubleType>" Name="Datalines"/>
> Thanks,
> Paul
>
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--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com
