Adding an XML attribute conditionally

Question

I need a way to add an XML attribute 'POSITON' to an XML element 'node' conditionally. Currently I'm doing the condition check first and then creating the node.

if (lvl == 2)
      node = <node COLOR={ color } CREATED={ epochTimeMillis } ID={ idGen } POSITION={ position } LINK={ link } MODIFIED={ epochTimeMillis } STYLE="bubble" TEXT={ f.getName() }>
               <edge COLOR={ color } STYLE={ style } WIDTH={ width }/>
             </node>
else
      node = <node COLOR={ color } CREATED={ epochTimeMillis } ID={ idGen } LINK={ link } MODIFIED={ epochTimeMillis } STYLE="bubble" TEXT={ f.getName() }>
               <edge COLOR={ color } STYLE={ style } WIDTH={ width }/>
             </node>
  }

senia · Accepted Answer · 2013-05-22 03:50:44Z

3

Using "null" is not a good practice, but in this case it would help you:

scala> <root ta={ if (true) "true" else null } fa={ if (false) "false" else null } />
res0: scala.xml.Elem = <root ta="true" ></root>

answered May 22, 2013 at 3:50

senia

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1 Comment

gosanjeev Over a year ago

Thanks, it worked. I was earlier trying with "" but should have used null.

cmbaxter · Accepted Answer · 2013-05-22 09:49:21Z

1

A slightly cleaner way to do the same thing @senia suggests is:

    val posOpt = if (lvl2) Some(myPosition) else None
    val xml = <mydata position={posOpt orNull}/>

answered May 22, 2013 at 9:49

cmbaxter

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Comments

Beryllium · Accepted Answer · 2013-05-22 09:49:28Z

0

One way is to create the snippet before:

val pos =
  if (lvl == 2) {
    "position = ..."
  } else {
    ""
  }

and to always insert it in the result.

This could by extended by using an Option with embedded map in combination with string interpolation.

val pos =
  if (lvl == 2) {
    Some(position)
  } else {
    None
  }

with

pos.map(v => s"position = $v")

answered May 22, 2013 at 9:49

Beryllium

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