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POHow to get a reference to a Lift MetaMapper object by name?
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  1. POHow to get a reference to a Lift MetaMapper object by name?
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    copied!<p>In modeling an audit table, I've included fields necessary to find the original record being audited (oid: String, className: String). I'd like to programmatically find the MetaMapper for the Mapper class name.</p> <p>For example, if I have:</p> <pre><code>class Foo extends Mapper[Foo] { def getSingleton = Foo } object Foo extends Foo with MetaMapper[Foo] { } </code></pre> <p>Given the String "Foo", how would I get a reference to the object Foo? Ultimately I want a reference to a MetaMapper so that I can do a findAll. In my Hibernate days I might have found a class using Class.byName(className) and then called a static method on that class.</p> <p>Here's what I'm using right now to do this, but it does require maintaining a list of MetaMapper objects and also instantiating classes using MetaMapper#create:</p> <pre><code>case class Audited(name: String, url: Box[String]) def getAudited : Box[Audited] = { // OBJECT_OID and OBJECT_TYPE are for the audited record we are trying to find (OBJECT_OID.is, OBJECT_TYPE.is) match { case (ooid, otype) if List(ooid,otype).forall(s =&gt; StringUtils.isNotBlank(s)) =&gt; { // maintain a list of objects that are metamappers val metas = List(Client) (for { // create a new instance and check its class name meta &lt;- metas.find(meta =&gt; meta.create.getClass.getName == otype) mapper &lt;- meta.find(By(meta.primaryKeyField, ooid)) } yield { val nameFieldNames = List("NAME") val name = mapper.allFields.find(f =&gt; nameFieldNames.contains(f.name)) match { case Some(field) =&gt; tryo(field.is.toString).openOr("") case _ =&gt; mapper.getClass.getName.split(".").last } Full(Audited(name, Empty)) }) openOr Empty } case _ =&gt; Empty } } </code></pre> <p>Which works, but it's ugly IMHO and requires maintenance of a list of supported MetaMappers</p>
 

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