parent ID checks

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@2717 1f8fe7d8-47f0-464c-8d0a-336f4953ab05
checkstyle fixes

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@2718 1f8fe7d8-47f0-464c-8d0a-336f4953ab05