// Create a class, use ", true" for "create it if it doesn't exist".
MetaModelClass personClass = namespace.getMetaClass(
"http://metaexample.org/meta#Person", true );
// Create a property in a similar way.
MetaModelProperty nameProperty = namespace.getMetaProperty(
"http://metaexample.org/meta#name", true );
// Tell the meta model that persons can have name properties.
personClass.getDirectProperties().add( nameProperty );
tx.success();