Re: [xwiki-devs] [Proposal][Model] ResourceName refactoring

On Tue, Dec 15, 2009 at 19:02, Vincent Massol <vincent(a)massol.net> wrote: > > On Dec 15, 2009, at 6:39 PM, Thomas Mortagne wrote: > >> On Tue, Dec 15, 2009 at 15:40, Vincent Massol <vincent(a)massol.net> >> wrote: >>> Hi, >>> >>> I'd like to propose a refactoring for org.xwiki.model.DocumentName/ >>> AttachmentName. >>> >>> There are currently 2 problems with the current implementation: >>> - DocumentName doesn't support nested spaces (we need that for the >>> future) >>> - We need to generalize the concept of resource names so that we can >>> use the generic concept in the Model in some APIs >>> >>> Thus I'd like to propose: >>> >>> enum ResourceType >>> - WIKI, DOCUMENT, SPACE, ATTACHMENT >>> >>> ResourceName >>> - ResourceName(String name, ResourceName parent) >>> - get/setName() >>> - get/setParent(ResourceName) >>> - get/setType(ResourceType) >>> >>> DocumentName extends ResourceName >>> - DocumentName(String pageName, SpaceName parent) >>> >>> AttachmentName extends ResourceName >>> - AttachmentName(String fileName, DocumentName parent) >>> >>> WikiName extends ResourceName >>> - WikiName(String wikiName) >>> >>> SpaceName extends ResourceName >>> - SpaceName(String spaceName, SpaceName parent) >>> - SpaceName(String spaceName, WikiName parent) >>> >>> Open questions and comments >>> ======================== >>> >>> - Should we replace "Name" by "Reference", i.e. DocumentReference >>> instead of DocumentName, WikiReference instead of WikiName? >> >> "Reference" or "Path" or something like that yes since it's not >> really a name. >> >>> - Note: A name (or reference) isn't resistant to change. Resources >>> (Document, Space, Wiki, etc) must also have an Identifier (unique id) >>> to uniquely identify them. For example a Document can be moved from >>> one space to another (the DocumentName changes in this case). >>> - The scheme above allows to map this easily to the JCR API >>> - Do we want helper methods for locating the wiki in which a >>> DocumentName is? That would mean adding: >>> WikiName DocumentName.getWiki() (algo: getParent() till getType == >>> WIKI or null) >>> Same question for getting the last Space or Wiki from AttachmentName >> >> Seems useful yes, we are using it a lot in the current DocumentName. >> >>> - Do we want a helper constructor to make it easier to create a >>> DocumentName? With the proposal above it means: >>> new DocumentName("page", new SpaceName("space", new >>> WikiName("wiki"))); >>> A helper constructor could be: DocumentName(String page, String >>> space, >>> String wiki). >> >> I don't think it's really necessary. We can always add it latter. >> >>> Problems: a) we would need another constructor to support a list of >>> spaces and b) if there are fields other than the name to set on >>> ResourceNames later on, it's not going to work as smoothly) >>> >>> Factory and Serializer >>> ================= >>> >>> This is a big question I haven't yet solved. We have 2 options: >>> 1) have specialized Factory/Serializer. For ex: DocumentNameFactory, >>> DocumentNameSerializer >>> 2) have generic ones: ResourceNameFactory/ResourceNameSerializer >>> >>> 2) seems nicer initially but the problem with 2) is that we need a >>> global String representation of any resource in the system. There are >>> 2 problems with that: >>> - we may not want that. For example when the user is asked to enter a >>> document name in a field, we may not need/want to parse this as a >>> general resource that could for example point to an attachment (and >>> btw as a consequence allow entering "@" which is our separator for >>> attachments) >>> - it's very hard to add new Resource types later on (since we'd need >>> more special characters to separate them and this means these chars >>> wouldn't be allowed in names for pages for ex) >> >> We need escaping support anyway, we can't continue to use a syntax >> that does not support all characters, it introduce important >> limitations for no reason. In a real syntax the special characters has >> nothing to do with the supported content... > > The factory cannot know if it needs to escape the '@' char (for e ex). > So it would the code handling the form (for ex) that would need to > escape characters depending on what it is expecting (it would need to > escape '@' for ex if it's expecting a document name and not escape it > if it's expecting an attachment name).

The factory does not escape anything. A factory take a string in some syntax (syntax including escaping syntax) and parse it to create an object where all the part of the names are separated and unescaped. You have to give it a proper string, i don't see what it has to do with HTML form. I you want the factory to not take care of the attachment syntax part then you use ResourceNameFactory.create(String stringRepresentation, ResourceType.DOCUMENT) you put in your proposal... Multi-factory does not bring any value, it's the opposite. It will just generate more classes and code duplicate. -- Thomas Mortagne