I am using a custom serialiser/deserialiser for draftjs, which creates a ContentState bottom-up, building a character metadata list with attached styles and Entities, creating the ContentBlock from that, and finally creates the ContentState using createFromBlockArray.
In v0.10, the Entity.create will be removed, and a ContentState instance will be required to create entities. How to create Entities when I don't yet have a ContentState instance?
Related
I am working on a use case where I have to dynamically add a new attribute to an existing object class in Apache DS.
1)Here is some code which defines my object class:--
Attributes attrs = new BasicAttributes(true);
attrs.put("NUMERICOID", "1.3.6.1.4.1.18060.0.4.3.3.1");
attrs.put("NAME", "ship");
attrs.put("DESC", "An entry which represents a ship");
attrs.put("SUP", "top");
attrs.put("STRUCTURAL", "true");
Attribute must = new BasicAttribute("MUST");
must.add("cn");
attrs.put(must);
Attribute may = new BasicAttribute("MAY");
may.add("numberOfGuns");
may.add("numberOfGuns2");
may.add("description");
attrs.put(may);
//add
schema.createSubcontext("ClassDefinition/ship", attrs);
2) Adding an object of that object class:
Attributes attributes=new BasicAttributes();
Attribute objectClass=new BasicAttribute("objectClass");
objectClass.add("ship");
attributes.put(objectClass);
Attribute g=new BasicAttribute("numberOfGuns");
Attribute g2=new BasicAttribute("numberOfGuns2");
Attribute cn=new BasicAttribute("cn");
g.add("2");
g2.add("3");
cn.add("four");
attributes.put(g);
attributes.put(cn);
attributes.put(g2);
;
ctx.createSubcontext("cn=four,dc=example,dc=com",attributes);
3) Add a new attribute -- 'mustA' to the object class
Attributes attrs = new BasicAttributes(true);
attrs.put("NUMERICOID", "1.3.6.1.4.1.18060.0.4.3.3.1");
attrs.put("NAME", "ship");
attrs.put("DESC", "An entry which represents a ship");
attrs.put("SUP", "top");
attrs.put("STRUCTURAL", "true");
Attribute must = new BasicAttribute("MUST");
must.add("cn");
must.add("mustA");
attrs.put(must);
Attribute may = new BasicAttribute("MAY");
may.add("numberOfGuns");
may.add("numberOfGuns2");
may.add("description");
attrs.put(may);
//modify
schema.modifyAttributes("ClassDefinition/ship",DirContext.ADD_ATTRIBUTE ,attrs);
Once the new attribute is added(which means object class is modified), If i add a new object of that object class type, I can see the newly added attribute in the newly created object.
My Question is, What happens to the objects which were created before I added the new attribute? How can I make the new attribute to show up in the exiting objects automatically? For example, here will the new attribute "mustA" automatically show up in object "four"?
Or Will I have to manually go and modify that object to add that new attribute?
You will need to update the schema. For ApacheDS the easiest method is to download Apache Studio and take a look at 2.3.1 - Adding Schema Elements
Oh, and you will always get great support from The Directory Users List for ApacheDS. The developers are very active.
AFIK, ApacheDs will support adding schema from LDAP calls, but I am not positive. (See The Directory Users List for ApacheDS)
If you insist doing this the hard way, check out the examples at:
http://docs.oracle.com/javase/jndi/tutorial/ldap/schema/object.html
-jim
My domain objects have a "CreateDate" and "ModidfyDate" members (DateTime).
When a user update a domain object (Asp.Net MVC) my view model does not hold these values. (It's to be set in my repository "Create" and "Update" methods)
So when I Update an object, I do not have the "CreateDate" available and therefore the Update method will fail.
I seems to have 2 options, and I don't like either:
1) Have my viewmodel tag along the "CreateDate" property (hidden field in form) so I have the original CreateDate available.
2) Or, in my "Update" repository method, first get the original record from the database and set the object I'm about to update's CreateDate member (an unnecessary call to the db)
What is the "normal" way to work with this?
A nice way to handle CreateDate and ModifyDate would be by using NHibernate's event listeners.
Here are some samples on how to create simple auditing using IPreInsertEventListener and IPreUpdateEventListener:
http://ayende.com/blog/3987/nhibernate-ipreupdateeventlistener-ipreinserteventlistener
http://nhforge.org/wikis/howtonh/creating-an-audit-log-using-nhibernate-events.aspx
On a side note, you shouldn't have problems with CreateDate on your Update method. How does your Update method look like?
The usual workflow is to get your view model in POST ActionMethod, load the entity object from the database using NHibernate's ISession, or your custom repository and then map your properties from the view model to the entity, either by hand, or using a tool like AutoMapper. Properties like CreateDate should be ignored in the viewmodel to entity mapping.
My application uses multiple threads with one managed object context per thread.
For clarity I will refer to the different managed object contexts as: moc1, moc2, ..., etc.
Let's assume we have two models with a simple one-many relationship:
User 1----* Document
When a user logs in I fetch the corresponding model from one of the contexts (eg. moc1).
(pseudo code)
UserModel *globalLoggedUser = ( Fetch the logged in user using moc1 )
I then store this user so that I can reference it later.
In another part of the application I need to loop through thousands of items from an array and create Document objects for it. Each document then needs to be bound to the current user. This happens in a different background thread (which has its own context)
for( NSString *documentName in documents) {
( Create new document using moc2 )
** THIS IS WHERE MY PROBLEM IS **
// What I currently do:
UserModel *tempUser = ( Fetch the logged in user using moc2 )
( bind new document to tempUser )
// What I would like to do:
( bind new document to globalLoggedUser )
// Note that in this case tempUser and globalLoggedUser are the same user, except they are attached to different contexts.
}
As you can see, I would like to avoid having to fetch a new user into the current context each time.
The problem is, globalLoggedUser is part of moc1, whereas the new document is part of moc2 (or moc3, moc4, etc, depends on the thread).
So what's the best way to go about this? How can I globally save/cache an object and then use that same object to bind relationships in different contexts without incurring a penalty of having to fetch each time?
Thanks for any help you can provide.
You are correct that you can't use the same NSManagedObject across threads.
From the Core Data Programming Guide:
Using thread confinement, you should not pass managed objects or managed object contexts between threads. To “pass” a managed object from one context another across thread boundaries, you either:
Pass its object ID (objectID) and use objectWithID: or existingObjectWithID:error: on receiving managed object context.
The corresponding managed objects must have been saved—you cannot pass the ID of a newly-inserted managed object to another context.
Execute a fetch on the receiving context.
I think you'd be fine if you just fetched the logged in user with moc2 before you run the 'document' loop, as I don't see any reason to do the fetch each time inside the loop. (Is there some reason you are doing that?)
Don't worry about binding anything to the UserModel from thread 1, the tempUser you get from moc2 is referencing the same data in the database as globalLoggedUser.
I am trying to construct an SQL statement dynamically.
My context is created dynamically, using reflection finding classes deriving from EntityTypeConfiguration and adding them to DbModelBuilder.Configuration.
My EntityTypeConfiguration classes specify HasColumnName to map the Entity property name to db table column name, which I need to construct my SQL statement.
namespace MyDomain {
public class TestEntityConfig : EntityTypeConfiguration<TestEntity>{
Property("Name").HasColumnName("dbName");
}
}
From What I have researched, it seems I can get access to this information through MetadataWorkspace, which I can get to through ObjectContext.
I have managed to retrieve the the entity I am interested in with MetadataWorkspace.GetItem("MyDomain.TestEntity",DataSpace.OSpace), which gives me access to Properties, but none of the properties, of Properties, give me the name of the mapped db column, as specified with HasColumnName.
Also I am not clear what DataSpace.OSpace is and why my model is constructed in this space.
If Anyone can shed some light on this I would be grateful
UPDATE
Further to #Ladislav's comments. I discovered I can get the information as follows
For the class properties
ctx.MetadataWorkspace.GetItem<ClrEntityType>("MyDomain.TestEntity", DataSpace.OSpace)).Members
For the table properties
ctx.MetadataWorkspace.GetItem<EntityType>("CodeFirstDatabaseSchema.TestEntity",SSpace).Members
So given that I only know the type MyDomain.TestEntity and Memeber "Name". How would I go about to get "dbName". Can I always assume that my mapped class will be created in CodeFirstDatabaseSchema, om order to dynamically construct the identity to retrieve it from SSpace and how would I get to the correct Member in SSpace. Can I do something like
var memIndex = ctx.MetadataWorkspace.GetItem<ClrEntityType>("MyDomain.TestEntity", DataSpace.OSpace)).Members["Name"].Index;
var dbName = ctx.MetadataWorkspace.GetItem<EntityType>("CodeFirstDatabaseSchema.TestEntity",SSpace).Members[memIndex];
MetadataWorkspace contanis several containers specified by DataSpace. Interesting for you are:
CSpace - description of conceptual model (this should contain properties)
CSSpace - mapping of conceptual model to storage model (this should contain how classes / properties are mapped to tables / columns)
NHibernate allows me to query a database and get an IList of objects in return. Suppose I get a list of a couple of dozen objects and modify a half-dozen or so. Does NHibernate have a way to persist changes to the collection, or do I have to persist each object as I change it?
Here's an example. Suppose I run the following code:
var hql = "from Project";
var query = session.CreateQuery(hql);
var myProjectList = query.List<Project>();
I will get back an IList that contains all projects. Now suppose I execute the following code:
var myNewProject = new Project("My New Project");
myProjectList .Add(myNewProject);
And let's say I do this several times, adding several new projects to the list. Now I'm ready to persist the changes to the collection.
I'd like to persist the changes by simply passing myProjectList to the current ISession for updating. But ISession.SaveOrUpdate() appears to take only individual objects, not collections like myProjectList. Is there a way that I can persist changes to myProjectList, or do I have to persist each new object as I create it? Thanks for your help.
David Veeneman
Foresight Systems
If you load objects like in your example - then yes you have to persist them one by one.
However, if you make a small design change, and load something like : Account that has an IList<Project> - if you specify cascade "what_cascade_you_need" in the mapping , then when you change the projects on Account , you only have to save Account and everything will get saved.