I do not understand the OrientGraphFactory class fully. Several questions:
1) What is the role of leaveGraphsOpen ? I cannot see any usage and/or examples.
public class OrientGraphFactory extends ... {
public boolean isLeaveGraphsOpen() {
return leaveGraphsOpen;
}
public void setLeaveGraphsOpen(boolean leaveGraphsOpen) {
this.leaveGraphsOpen = leaveGraphsOpen;
}
}
2) Why two public getDatabase() methods? This is a factory for Graph databases
3) I only want to auto create the database in specific situations (in our app, only when in "setting up mode". The only way to achieve this is:
final boolean autoCreate = false;
this.factory = new OrientGraphFactory(url) {
#Override
public ODatabaseDocumentTx getDatabase(boolean iCreate, boolean iOpen) {
return super.getDatabase(autoCreate, iOpen);
}
}.setupPool(1, 5); // default: no pool (instances are created on demand)
Is this the correct way of doing this? Looks very ugly :(
This is not supported out of the box, so your solution should work and use the wonderful Object Orientation.
Related
Is there any way to make a listener fire once and remove itself?
for(Spec spec : specs){
spec.myProperty().addListener((obs,ov,nv) -> {
if (nv.longValue() > 0){
//do whatever
spec.myProperty().removeListener(this);
}
});
}
That code won't work. I can only think of complicated solutions to this seemingly simple problem.
How about using an anonymous inner class instead of a lambda expression?
IntegerProperty property = new SimpleIntegerProperty();
InvalidationListener listener = new InvalidationListener() {
#Override
public void invalidated(Observable observable) {
//TODO do something
property.removeListener(this);
}
};
property.addListener(listener);
The answer was partly in the comments so I'll add my [brian] solution here.
public void someMethod(){
for(Spec spec : specs){
spec.myProperty().addListener(listener);
}
}
ChangeListener<Number> listener = new ChangeListener<Number>() {
public void changed(ObservableValue<? extends Number> obs, Number ov, Number nv) {
Spec spec = (Spec)((SimpleLongProperty)obs).getBean();
spec.myProperty().removeListener(this);
}
};
Note, when I create myProperty in the Spec class I use the full constructor to specify the bean. new SimpleLongProperty(this, "myProperty", 0l);
Even doing this you still can't use a lambda to remove this.
I've just started a project built with the new GWT archetype.
ActivityMapper looks like:
public interface Factory {
HomeActivity homeActivity();
GreetingActivity greetingActivity(String user);
}
private final Factory factory;
#Inject
MainActivityMapper(Factory factory) {
this.factory = factory;
}
#Override
public Activity getActivity(Place place) {
if (place instanceof HomePlace) {
return factory.homeActivity();
}
if (place instanceof GreetingPlace) {
GreetingPlace greetingPlace = (GreetingPlace) place;
return factory.greetingActivity(greetingPlace.getUser());
}
logger.severe("Unhandled place type: " + place.getClass().getName());
return null;
}
I'm now trying to implement code split with AsyncProvider based on this example, but I can't get it working.
When using ActivityAsyncProxy, what should I do? return the ActivityAsyncProxy from getActivity(Place place)? but then, how can I create the ActivityAsyncProxy from the factory?
How would you suggest to make the activity mapper play nicely with code split?
AFAICT, you cannot use AsyncProvider with assisted inject (that would be a great addition to GIN). That means you cannot benefit from generated runAsync calls, you'd have to do them yourself.
Have a look at http://code.google.com/p/google-web-toolkit/issues/detail?id=5129 for discussion of this issue, with several proposals.
Also have a look at https://groups.google.com/d/msg/google-web-toolkit-contributors/bUFYWEFskBI/ja2aJ0tBgdwJ for my own take on it (also available at https://gist.github.com/3038878).
I'd like to know how I can have Imports in my custom ExportProvider. Here's an example of what I'm trying to do:
public class MyExportProvider : ExportProvider
{
private List<Export> _exports;
[Import()]
private IConfig _config;
public MyExportProvider()
base()
{
_exports = new List<Export>();
}
protected override IEnumerable<Export> GetExportsCore(ImportDefinition definition,
AtomicComposition composition)
{
if (!_exports.Any())
Initialize();
return _exports.Where(x => definition.IsConstraintSatisfiedBy(s.Definition);
}
private void Initialize()
{
var contractName = typeof(MyObject).FullName;
var exportDefinition = new ExportDefinition(contractName, null);
var export = new Export(exportDefinition, () => new MyObject(_config));
_exports.Add(export);
}
}
I am adding the provider when I create the CompositionContainer.
Unfortunately, the import is never satisfied. I can see this by setting AllowDefaults = true so my provider is created, but _config is always null.
How can I configure the container and/or provider so the Import will be satisfied?
When you are adding your export provider you are still creating your composition container. Thus I don't see how you can use the not yet created composition container to import parts of your custom export provider.
What I would do is first create a temporary CompositionContainer that will be used to create MyExportProvider.
Afterwards use the MyExportProvider to create your second final CompositionContainer that will be used by the rest of the application.
EDIT:
// this is your real container, only shown here for reference
CompositionContainer container;
public void BootstrapContainerMethod()
{
// Replace this part with the catalogs required to create your export provider.
var catalog = new AggregateCatalog();
catalog.Catalogs.Add(new DirectoryCatalog("./bin", "*.dll"));
// Your temporary container, declared here in local scope
// will be disposed because of using
using (var bootstrapContainer = new CompositionContainer(catalog))
{
var myExportProvider = bootstrapContainer.GetExportedValue<IMyExportProvider>();
// create your real container and optionnally add catalogs (not shown here)
container = new CompositionContainer(myExportProvider);
}
}
You might also consider the problem from another angle. Do you really need to have imports in your custom ExportProvider? I do not know your requirements, but maybe you can make do without having imports.
As an alternative to the dual CompositionContainer solution, you could wire this up in a single export provider, and have it compose itself using the same container. As an example, I've defined the following contract and it's export:
public interface ILogger
{
void Log(string message);
}
[Export(typeof(ILogger))]
public class ConsoleLogger : ILogger
{
public void Log(string message)
{
Console.WriteLine(message);
}
}
And with my example ExportProvider, I expect to be able to import an instance of it:
public class TestExportProvider : ExportProvider
{
private readonly object _lock = new object();
private bool _initialised;
[Import]
public ILogger Logger { get; set; }
public void SetCompositionService(ICompositionService service)
{
if (service == null) throw new ArgumentNullException("service");
lock (_lock)
{
if (!_initialised)
{
InitialiseProvider(service);
}
}
}
private void InitialiseProvider(ICompositionService service)
{
service.SatisfyImportsOnce(this);
_initialised = true;
}
protected override IEnumerable<Export> GetExportsCore(ImportDefinition definition, AtomicComposition atomicComposition)
{
if (_initialised)
{
Logger.Log("Getting available exports for '" + definition.ContractName + "'");
// Do work here.);
return Enumerable.Empty<Export>();
}
return Enumerable.Empty<Export>();
}
}
I provide an instance of an ICompositionService, which CompositionContainer implements, and I perform a first-time initialisation when I call SetCompositionService. It checks to see if it has already been initialised, and if not, goes ahead and calls the SatisfyImportsOnce method on itself.
We would wire this up, something like this:
// Build our catalog.
var catalog = new AssemblyCatalog(typeof(Program).Assembly);
// Create our provider.
var provider = new TestExportProvider();
// Create our container.
var container = new CompositionContainer(catalog, provider);
// Register the composition service to satisfy it's own imports.
provider.SetCompositionService(container);
Obviously you wouldn't be able to use any imports and your ExportProvider will explicitly create for you, but for everything else, it should work.
I'm trying to create a page which is very similar to the Google Form creation page.
This is how I am attempting to model it using the GWT MVP framework (Places and Activities), and Editors.
CreateFormActivity (Activity and presenter)
CreateFormView (interface for view, with nested Presenter interface)
CreateFormViewImpl (implements CreateFormView and Editor< FormProxy >
CreateFormViewImpl has the following sub-editors:
TextBox title
TextBox description
QuestionListEditor questionList
QuestionListEditor implements IsEditor< ListEditor< QuestionProxy, QuestionEditor>>
QuestionEditor implements Editor < QuestionProxy>
QuestionEditor has the following sub-editors:
TextBox questionTitle
TextBox helpText
ValueListBox questionType
An optional subeditor for each question type below.
An editor for each question type:
TextQuestionEditor
ParagraphTextQuestionEditor
MultipleChoiceQuestionEditor
CheckboxesQuestionEditor
ListQuestionEditor
ScaleQuestionEditor
GridQuestionEditor
Specific Questions:
What is the correct way to add / remove questions from the form. (see follow up question)
How should I go about creating the Editor for each question type? I attempted to listen to the questionType value changes, I'm not sure what to do after. (answered by BobV)
Should each question-type-specific editor be wrapper with an optionalFieldEditor? Since only one of can be used at a time. (answered by BobV)
How to best manage creating/removing objects deep in the object hierarchy. Ex) Specifying answers for a question number 3 which is of type multiple choice question. (see follow up question)
Can OptionalFieldEditor editor be used to wrap a ListEditor? (answered by BobV)
Implementation based on Answer
The Question Editor
public class QuestionDataEditor extends Composite implements
CompositeEditor<QuestionDataProxy, QuestionDataProxy, Editor<QuestionDataProxy>>,
LeafValueEditor<QuestionDataProxy>, HasRequestContext<QuestionDataProxy> {
interface Binder extends UiBinder<Widget, QuestionDataEditor> {}
private CompositeEditor.EditorChain<QuestionDataProxy, Editor<QuestionDataProxy>> chain;
private QuestionBaseDataEditor subEditor = null;
private QuestionDataProxy currentValue = null;
#UiField
SimplePanel container;
#UiField(provided = true)
#Path("dataType")
ValueListBox<QuestionType> dataType = new ValueListBox<QuestionType>(new Renderer<QuestionType>() {
#Override
public String render(final QuestionType object) {
return object == null ? "" : object.toString();
}
#Override
public void render(final QuestionType object, final Appendable appendable) throws IOException {
if (object != null) {
appendable.append(object.toString());
}
}
});
private RequestContext ctx;
public QuestionDataEditor() {
initWidget(GWT.<Binder> create(Binder.class).createAndBindUi(this));
dataType.setValue(QuestionType.BooleanQuestionType, true);
dataType.setAcceptableValues(Arrays.asList(QuestionType.values()));
/*
* The type drop-down UI element is an implementation detail of the
* CompositeEditor. When a question type is selected, the editor will
* call EditorChain.attach() with an instance of a QuestionData subtype
* and the type-specific sub-Editor.
*/
dataType.addValueChangeHandler(new ValueChangeHandler<QuestionType>() {
#Override
public void onValueChange(final ValueChangeEvent<QuestionType> event) {
QuestionDataProxy value;
switch (event.getValue()) {
case MultiChoiceQuestionData:
value = ctx.create(QuestionMultiChoiceDataProxy.class);
setValue(value);
break;
case BooleanQuestionData:
default:
final QuestionNumberDataProxy value2 = ctx.create(BooleanQuestionDataProxy.class);
value2.setPrompt("this value doesn't show up");
setValue(value2);
break;
}
}
});
}
/*
* The only thing that calls createEditorForTraversal() is the PathCollector
* which is used by RequestFactoryEditorDriver.getPaths().
*
* My recommendation is to always return a trivial instance of your question
* type editor and know that you may have to amend the value returned by
* getPaths()
*/
#Override
public Editor<QuestionDataProxy> createEditorForTraversal() {
return new QuestionNumberDataEditor();
}
#Override
public void flush() {
//XXX this doesn't work, no data is returned
currentValue = chain.getValue(subEditor);
}
/**
* Returns an empty string because there is only ever one sub-editor used.
*/
#Override
public String getPathElement(final Editor<QuestionDataProxy> subEditor) {
return "";
}
#Override
public QuestionDataProxy getValue() {
return currentValue;
}
#Override
public void onPropertyChange(final String... paths) {
}
#Override
public void setDelegate(final EditorDelegate<QuestionDataProxy> delegate) {
}
#Override
public void setEditorChain(final EditorChain<QuestionDataProxy, Editor<QuestionDataProxy>> chain) {
this.chain = chain;
}
#Override
public void setRequestContext(final RequestContext ctx) {
this.ctx = ctx;
}
/*
* The implementation of CompositeEditor.setValue() just creates the
* type-specific sub-Editor and calls EditorChain.attach().
*/
#Override
public void setValue(final QuestionDataProxy value) {
// if (currentValue != null && value == null) {
chain.detach(subEditor);
// }
QuestionType type = null;
if (value instanceof QuestionMultiChoiceDataProxy) {
if (((QuestionMultiChoiceDataProxy) value).getCustomList() == null) {
((QuestionMultiChoiceDataProxy) value).setCustomList(new ArrayList<CustomListItemProxy>());
}
type = QuestionType.CustomList;
subEditor = new QuestionMultipleChoiceDataEditor();
} else {
type = QuestionType.BooleanQuestionType;
subEditor = new BooleanQuestionDataEditor();
}
subEditor.setRequestContext(ctx);
currentValue = value;
container.clear();
if (value != null) {
dataType.setValue(type, false);
container.add(subEditor);
chain.attach(value, subEditor);
}
}
}
Question Base Data Editor
public interface QuestionBaseDataEditor extends HasRequestContext<QuestionDataProxy>, IsWidget {
}
Example Subtype
public class BooleanQuestionDataEditor extends Composite implements QuestionBaseDataEditor {
interface Binder extends UiBinder<Widget, BooleanQuestionDataEditor> {}
#Path("prompt")
#UiField
TextBox prompt = new TextBox();
public QuestionNumberDataEditor() {
initWidget(GWT.<Binder> create(Binder.class).createAndBindUi(this));
}
#Override
public void setRequestContext(final RequestContext ctx) {
}
}
The only issue left is that QuestionData subtype specific data isn't being displayed, or flushed. I think it has to do with the Editor setup I'm using.
For example, The value for prompt in the BooleanQuestionDataEditor is neither set nor flushed, and is null in the rpc payload.
My guess is: Since the QuestionDataEditor implements LeafValueEditor, the driver will not visit the subeditor, even though it has been attached.
Big thanks to anyone who can help!!!
Fundamentally, you want a CompositeEditor to handle cases where objects are dynamically added or removed from the Editor hierarchy. The ListEditor and OptionalFieldEditor adaptors implement CompositeEditor.
If the information required for the different types of questions is fundamentally orthogonal, then multiple OptionalFieldEditor could be used with different fields, one for each question type. This will work when you have only a few question types, but won't really scale well in the future.
A different approach, that will scale better would be to use a custom implementation of a CompositeEditor + LeafValueEditor that handles a polymorphic QuestionData type hierarchy. The type drop-down UI element would become an implementation detail of the CompositeEditor. When a question type is selected, the editor will call EditorChain.attach() with an instance of a QuestionData subtype and the type-specific sub-Editor. The newly-created QuestionData instance should be retained to implement LeafValueEditor.getValue(). The implementation of CompositeEditor.setValue() just creates the type-specific sub-Editor and calls EditorChain.attach().
FWIW, OptionalFieldEditor can be used with ListEditor or any other editor type.
We implemented similar approach (see accepted answer) and it works for us like this.
Since driver is initially unaware of simple editor paths that might be used by sub-editors, every sub-editor has own driver:
public interface CreatesEditorDriver<T> {
RequestFactoryEditorDriver<T, ? extends Editor<T>> createDriver();
}
public interface RequestFactoryEditor<T> extends CreatesEditorDriver<T>, Editor<T> {
}
Then we use the following editor adapter that would allow any sub-editor that implements RequestFactoryEditor to be used. This is our workaround to support polimorphism in editors:
public static class DynamicEditor<T>
implements LeafValueEditor<T>, CompositeEditor<T, T, RequestFactoryEditor<T>>, HasRequestContext<T> {
private RequestFactoryEditorDriver<T, ? extends Editor<T>> subdriver;
private RequestFactoryEditor<T> subeditor;
private T value;
private EditorDelegate<T> delegate;
private RequestContext ctx;
public static <T> DynamicEditor<T> of(RequestFactoryEditor<T> subeditor) {
return new DynamicEditor<T>(subeditor);
}
protected DynamicEditor(RequestFactoryEditor<T> subeditor) {
this.subeditor = subeditor;
}
#Override
public void setValue(T value) {
this.value = value;
subdriver = null;
if (null != value) {
RequestFactoryEditorDriver<T, ? extends Editor<T>> newSubdriver = subeditor.createDriver();
if (null != ctx) {
newSubdriver.edit(value, ctx);
} else {
newSubdriver.display(value);
}
subdriver = newSubdriver;
}
}
#Override
public T getValue() {
return value;
}
#Override
public void flush() {
if (null != subdriver) {
subdriver.flush();
}
}
#Override
public void onPropertyChange(String... paths) {
}
#Override
public void setDelegate(EditorDelegate<T> delegate) {
this.delegate = delegate;
}
#Override
public RequestFactoryEditor<T> createEditorForTraversal() {
return subeditor;
}
#Override
public String getPathElement(RequestFactoryEditor<T> subEditor) {
return delegate.getPath();
}
#Override
public void setEditorChain(EditorChain<T, RequestFactoryEditor<T>> chain) {
}
#Override
public void setRequestContext(RequestContext ctx) {
this.ctx = ctx;
}
}
Our example sub-editor:
public static class VirtualProductEditor implements RequestFactoryEditor<ProductProxy> {
interface Driver extends RequestFactoryEditorDriver<ProductProxy, VirtualProductEditor> {}
private static final Driver driver = GWT.create(Driver.class);
public Driver createDriver() {
driver.initialize(this);
return driver;
}
...
}
Our usage example:
#Path("")
DynamicEditor<ProductProxy> productDetailsEditor;
...
public void setProductType(ProductType type){
if (ProductType.VIRTUAL==type){
productDetailsEditor = DynamicEditor.of(new VirtualProductEditor());
} else if (ProductType.PHYSICAL==type){
productDetailsEditor = DynamicEditor.of(new PhysicalProductEditor());
}
}
Would be great to hear your comments.
Regarding your question why subtype specific data isn't displayed or flushed:
My scenario is a little bit different but I made the following observation:
GWT editor databinding does not work as one would expect with abstract editors in the editor hierarchy. The subEditor declared in your QuestionDataEditor is of type QuestionBaseDataEditor and this is fully abstract type (an interface). When looking for fields/sub editors to populate with data/flush GWT takes all the fields declared in this type. Since QuestionBaseDataEditor has no sub editors declared nothing is displayed/flushed. From debugging I found out that is happens due to GWT using a generated EditorDelegate for that abstract type rather than the EditorDelegate for the concrete subtype present at that moment.
In my case all the concrete sub editors had the same types of leaf value editors (I had two different concrete editors one to display and one to edit the same bean type) so I could do something like this to work around this limitation:
interface MyAbstractEditor1 extends Editor<MyBean>
{
LeafValueEditor<String> description();
}
// or as an alternative
abstract class MyAbstractEditor2 implements Editor<MyBean>
{
#UiField protected LeafValueEditor<String> name;
}
class MyConcreteEditor extends MyAbstractEditor2 implements MyAbstractEditor1
{
#UiField TextBox description;
public LeafValueEditor<String> description()
{
return description;
}
// super.name is bound to a TextBox using UiBinder :)
}
Now GWT finds the subeditors in the abstract base class and in both cases I get the corresponding fields name and description populated and flushed.
Unfortunately this approach is not suitable when the concrete subeditors have different values in your bean structure to edit :(
I think this is a bug of the editors framework GWT code generation, that can only be solved by the GWT development team.
Isn't the fundamental problem that the binding happens at compile time so will only bind to QuestionDataProxy so won't have sub-type specific bindings? The CompositeEditor javadoc says "An interface that indicates that a given Editor is composed of an unknown number of sub-Editors all of the same type" so that rules this usage out?
At my current job I'm pushing to avoid polymorphism altogether as the RDBMS doesn't support it either. Sadly we do have some at the moment so I'm experimenting with a dummy wrapper class that exposes all the sub-types with specific getters so the compiler has something to work on. Not pretty though.
Have you seen this post: http://markmail.org/message/u2cff3mfbiboeejr this seems along the right lines.
I'm a bit worried about code bloat though.
Hope that makes some sort of sense!
This question relates to my other post.
Ok so after a bit more messing around I decided to do it this way. Which seems to work fine when I run it, although I'm getting the following error in NUnit: Could not load file or assembly 'Castle.Core, Version=1.0.3.0, Culture=neutral, PublicKeyToken=407dd0808d44fbdc' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040) So not sure what is happening there???
Just wanted to know what others thought about the design and if there are any obvious 'no no's' or improvements. I.e. Is the constructor of the base handler a good place to instantiate the windsor component or is there a better place to do this? As I said in the original post the idea behind doing things this way was to keep the components nicely decoupled and to make unit testing easy. I should also add I'm new to unit testing, mocking. Thanks!
public abstract class BaseHttpHandler : IHttpHandler
{
private HttpContext _httpContext;
private ILogger _logger;
private IDataRepository _dataRepository;
protected HttpRequest Request { get { return _httpContext.Request; } }
protected HttpResponse Response { get { return _httpContext.Response; } }
protected bool IsRequestFromUAD { get { return Request.UserAgent == null ? false : Request.UserAgent.Equals("UAD"); } }
protected ILogger Logger { get { return _logger; } }
protected IDataRepository DataRepository { get { return _dataRepository; } }
public virtual bool IsReusable { get { return false; } }
public BaseHttpHandler()
{
var container = new WindsorContainer(new XmlInterpreter(new ConfigResource("castle")));
_logger = container.Resolve<ILogger>();
_dataRepository = container.Resolve<IDataRepository>();
}
public void ProcessRequest(HttpContext context)
{
_httpContext = context;
ProcessRequest(new HttpContextWrapper(context));
}
public abstract void ProcessRequest(HttpContextBase context);
}
public class UADRecordHttpHandler : BaseHttpHandler
{
public override void ProcessRequest(HttpContextBase context)
{
if (IsRequestFromUAD)
{
using (var reader = new StreamReader(context.Request.InputStream))
{
string data = reader.ReadToEnd();
if (Logger != null)
Logger.Log(data);
if(DataRepository != null)
DataRepository.Write(data);
context.Response.Write(data);
}
}
else
ReturnResponse(HttpStatusCode.BadRequest);
}
}
That's a very bad thing to do, what you're doing here. You should have one instance of the container per application, while with this code you will have one per each request.
About the error in NUnit: make sure you don't have other versions of Castle assemblies in the GAC. If so, uninstall them.
About your BaseHttpHandler: the problem with this implementation is that you're creating a new container. Instead, use a single container per application, like Krzysztof said. Use a static service locator, e.g. CommonServiceLocator. (I never recommend this but it's one of the few places where it does make sense).