Null (query directive)
From WandoraWiki
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== Examples == | == Examples == | ||
| − | + | Following example gets the superclass of input topic or null if it does not have a superclass. | |
importPackage(org.wandora.query2); | importPackage(org.wandora.query2); | ||
| Line 16: | Line 16: | ||
new Players(XTMPSI.SUPERCLASS_SUBCLASS,XTMPSI.SUPERCLASS) | new Players(XTMPSI.SUPERCLASS_SUBCLASS,XTMPSI.SUPERCLASS) | ||
.whereInputIs(XTMPSI.SUBCLASS), | .whereInputIs(XTMPSI.SUBCLASS), | ||
| − | new | + | new If.COND(), |
| − | + | ||
new Null().as(XTMPSI.SUPERCLASS) | new Null().as(XTMPSI.SUPERCLASS) | ||
) | ) | ||
[[Category:Query directives]] | [[Category:Query directives]] | ||
Latest revision as of 13:22, 25 August 2009
[edit] Description
Returns then null value
[edit] Constructor
Null()
[edit] Examples
Following example gets the superclass of input topic or null if it does not have a superclass.
importPackage(org.wandora.query2); importPackage(org.wandora.topicmap); new If( new Players(XTMPSI.SUPERCLASS_SUBCLASS,XTMPSI.SUPERCLASS) .whereInputIs(XTMPSI.SUBCLASS), new If.COND(), new Null().as(XTMPSI.SUPERCLASS) )
