What is the difference between the Blueprints methods vertex.addProperty(key, value); implemented in TitanVertex and vertex.setProperty(key, value); in Element?
If there is a difference, how can I translate addProperty into setProperty?
Titan has the notion of multi-properties which is not a part of the Blueprints API. A multi-property "allows a list of values on this property key for each vertex. This is useful when a property key is multi-valued, like "email" for example, since a user can have multiple email addresses".
If you use multi-properties then you can only set them via TitanVertex.addProperty. You can't set them via any Blueprints methods.
Related
I have an app with two regions, one serving as a selector for data type (called NavigationPane) and the other one as a setter view for that data type (called SimulationPane). The SimulatorView.xaml I use to fill the SimulationPane has a corresponding SimulatorViewModel which dynamically creates a list of settable properties for TDataType and eventually binds it to a ItemsControl in SimulatorView.xaml. So my ViewModel needs System.Type as input:
I want to set it up as following:
public void RegisterTypes(IContainerRegistry containerRegistry)
{
containerRegistry.RegisterForNavigation<TopicSelectorView, TopicSelectorViewModel>("Selector");
containerRegistry.RegisterForNavigation<SimulatorView, SimulatorViewModel<A>>("Simulator_A");
containerRegistry.RegisterForNavigation<SimulatorView, SimulatorViewModel<B>>("Simulator_B"); // and so on..
}
Once I have it registered, I want to be able to call (from other module):
regionManager.RequestNavigate("SimulationPane", $"Simulator_{topicType.Name}");
where topicType is the data type based on user's selection (here: 'A', 'B', and so on).
The problem with this approach is that I end up with just one ViewModel, i.e. the one I registered last. My impression is that that the registration uses some kind of dictionary with view as a key.
What am I doing wrong here? How else can I achieve my goal of being able to provide a type for VM at runtime, and navigate to it?
How else can I achieve my goal of being able to provide a type for VM at runtime, and navigate to it?
Register multiple viewmodels with the same view is not supported in Prism. See #brianlagunas answer on GitHub:
As I said in my reply to your PR, this is not something we will support in Prism. You have a few options, two of which we have already discussed; create a unique view, or have a single VM and load the relevant data.
Why do you need to pass A and B as generic parameters?
I'd have a single SimulatorViewModel and inject a service from which the view model can get the list of parameters to be set by the user. This could be done through reflection (on the simulator type) or a list of parameter descriptors (IReadOnlyCollection<Parameter> ISimulator.Parameters { get; }), whatever you prefer.
When changing the simulator type, you update it in the service and the SimulatorViewModel updates its list of parameters, because it listens to the service's INotifyPropertyChanged.PropertyChanged.
My model consisted of the following example:
class Aggregate {
private SomeClassWithFields property;
}
Now I decided to introduce inheritance to SomeClassWithFields. This results in:
class Aggregate {
private AbstractBaseClass property;
}
The collection already contains a lot of documents. These documents do not contain a _class property inside the DB since they were stored before the inheritance was present.
Is there a way to tell Spring Data MongoDB to use SomeClassWithFields as the default implementation of AbstractBaseClass if no _class property is present?
The other solution would be to add the _class to all the existing documents with a script but this would take some time since we have a lot of documents.
I solved it by using an AbstractMongoEventListener
The AbstractMongoEventListener has an onAfterLoad method which I used to set the default _class value if none was present :) This method is called before any mapping from the DBObject to my domain model by spring so it works then.
Do note that I also needed to let spring data mongodb know the mappingBasePackage in order for it to be able to read an Aggregate before writing one. This can be done implementing the getMappingBasePackage method of the PreconfiguredAbstractMongoConfiguration class.
I am trying to port CookXml to codenameone so I can use it to define UI in xml. CookXml depends on w3c dom and javax parser. I am looking for a way to replace the javax document builder class with the XMLParser in codenameone. I am stumped by the fact that even though XMLParser is supposed to be a close port I don't seem to be able to identify what to use to get attributes or the Attr node. Is the element in XMLParser the same as the Attr node? Or is it not just supported? How would I for instance be able to get names of attributes for an element?
XMLParser unified the concepts of Node, Document, Element etc. into a single Element class.
Attributes are simplified when compared to the DOM attributes.
To get the attributes you can just call:
Hashtable<String, String> h = (Hashtable<String, String>)elem.getAttributes();
Then to get all the attribute names/values:
for(String key : h.keySet()) {
String value = h.get(key);
....
}
I think I might be missing something, but I can't see how to use the built in multi-select picklist control for anything but sObject fields.
I'm talking about the control which features 2 list objects marked "Available" and "Selected" with arrows inbetween to moving items between the lists. This control is an easier and more discoverable way for a user to select several items then the selectList control, which needs Shift and Ctrl to select multiple items.
Page with pictured example
With a selectList I don't need a specific sObject - I can store the users selection in one off my controllers members, and I can even create a method to provide a list of valid values - this method could be hard coded, dynamically calculated or even use a query to lookup some live data.
Is there a way to use the fancy picklist control, only without any reference to a specific sObject, just a list of string values?
Unfortunately, the only way to use any of the standard field types, e.g., dates or multi-select picklists, is to have the field be backed by an SObject.
For me, when it becomes necessary to use these kinds of fields on a Visualforce page, I will create an Object specifically for the purpose of providing a back-end for the fields. In the Apex Controller, simply instantiate your Object (no need to supply any values) and reference that object's fields on the page.
While this may seem a little inefficient from the configuration side, it has a number of added benefits such as using the default UI (automatically subject to any improvements made by SFDC) and utilizing any built in validation.
If you are dead-set on not having the field be backed by an SObject, there might be some jquery multi-select options available. I've seen a lot around but haven't really tested any.
in your class:
public List<SelectOption> getStoryItems()
{
List<SelectOption> options = new List<SelectOption>();
options.add(new SelectOption('SAM','Sam I Am'));
options.add(new SelectOption('GEORGE','George of the Jungle'));
options.add(new SelectOption('DORA','Dora the Explorer'));
return options;
}
String[] stories= new String[]{};
public String[] getStories()
{
return stories;
}
public void setStories(String[] stories)
{
this.stories= stories;
}
in your page:
<apex:selectList value="{!stories}" multiselect="true">
<apex:selectOptions value="{!getStoryItems}"/>
</apex:selectList>
The results will be comma delimited, if you don't want multiple select, just set multiselect to false
I want to ensure an object is unique, and to throw an error when a user tries to save it (e.g. via the admin) if not? By unique, I mean that some of the object's attributes might hold the same values as those of other objects, but they can't ALL be identical to another object's values.
If I'm not mistaken, I can do this like so:
class Animal(models.Model):
common_name = models.CharField(max_length=150)
latin_name = models.CharField(max_length=150)
class Meta:
unique_together = ("common_name", "latin_name")
But then each time I refactor the model (e.g. to add a new field, or to change the name of an existing field), I also have to edit the list of fields in the parenthesis assigned to unique_together. With a simple model, that's OK, but with a substantial one, it becomes a real hassle during refactoring.
How can I avoid having to repeat typing out the list of field names in the unique_together parenthesis? Is there some way to pass the list of the model's fields to a variable and to assign that variable to unique_together instead?
Refactoring models is a rather expensive thing to do:
You will need to change all code using your models since field names correspond to object properties
You will have to change your database manually since Django cannot do this for you (at least the version I used the last time when I worked with Django couldn't)
Therefore I think updating the list of unique field names in the model meta class is the least issue you should worry about.
EDIT: If you really want to do this and all of your fields must be "unique together", then the guy at freenode is right and you'll have to write a custom metaclass. This is quite complicated and errorprone, plus it might render your code incompatible to future releases of Django.
Django's ORM "magic" is controlled by the metaclass ModelBase (django.db.models.base.ModelBase) of the generic base class Model. This class is responsible to take your class definition with all fields and Meta information and construct the class you will be using in your code later.
Here is a recipe on how you could achieve your goal:
Subclass ModelBase to use your own metaclass.
Override the method __new__(cls, name, bases, dict)
Inspect dict to gather the Meta member (dict["Meta"]) as well as all field members
Set meta.unique_together based on the names of the fields you gathered.
Call the super implementation (ModelBase.__new__)
Use the custom metaclass for all your unique models using the magic member __metaclass__ = MyMetaclass (or derive an abstract base class extending Model and overriding the metaclass)