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From Norman Maurer <nor...@apache.org>
Subject Re: Double ColumnType and comparing
Date Mon, 14 Mar 2011 17:26:48 GMT
I will have a look at what it takes to implement it..

Bye,
Norman


2011/3/14 David Boxenhorn <david@taotown.com>

> I you do it, I'd recommend BigDecimal. It's an exact type, and usually what
> you want.
>
> On Mon, Mar 14, 2011 at 3:40 PM, Jonathan Ellis <jbellis@gmail.com> wrote:
>
>> We'd be happy to commit a patch contributing a DoubleType.
>>
>> On Sun, Mar 13, 2011 at 7:36 PM, Paul Teasdale <teasdalep@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
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>>
>>
>>
>> --
>> Jonathan Ellis
>> Project Chair, Apache Cassandra
>> co-founder of DataStax, the source for professional Cassandra support
>> http://www.datastax.com
>>
>
>

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