Which NetTopologySuite Index is optimal for include and exclude rectangle search - spatial-index

I have a following problem: huge number of points and huge number of queries which need to provide as fast as possible any point that is inside include rectangle (red) and outside exclude rectangle (green). As number of points is huge and rectangles can be of various sizes it would be best to use some spatial index, but as far as I see all Query functions in NetTopologySuite.Index return lists with all results, where I need any single result and so queries are too expensive when big rectangle with many points comes.
Did I miss some spatial index which will solve my problem? Or some nice trick to solve it fast? I could use visitors but they are evaluated for every node, I could use Exception to break out when element found, but that looks ugly.

You can query the indices using a custom IItemVisitor{T} that would exclude items intersecting the green rectangle. Sth along these lines:
/// <summary>
/// Item visitor that specifically excludes a predefined area.
/// </summary>
/// <typeparam name="T">The type of the items to visit</typeparam>
public class ExcludingItemVisitor<T> : IItemVisitor<T> where T:Geometry
{
private readonly Envelope _exclude;
private readonly List<T> _items = new List<T>();
/// <summary>
/// Initialize with <paramref name="exclude"/>
/// </summary>
/// <param name="exclude"></param>
public ExcludingItemVisitor(Envelope exclude)
{
_exclude = exclude;
}
/// <inheritdoc cref="IItemVisitor{T}.VisitItem"/>>
public void VisitItem(T item)
{
// If we have no intersection with _exclude, add it.
if (!_exclude.Intersects(item.EnvelopeInternal))
_items.Add(item);
}
/// <summary>
/// Get a value indicating the gathered items
/// </summary>
public IList<T> Items => _items;
}

Related

how to pass value from one WaterfallDialog to another WaterfallDialog in ComponentDialog

bot framework v4
I have two WaterfallDialogs in ComponentDialog.
I could store value like below in WaterfallDialogs
step.values[currenctCategory] = result;
but when i prompt another second WaterfallDialog from the first WaterfallDialog
, i could not get the step.values[currenctCategory] in second WaterfallDialog
You need to use the State to store the intermediate values that you will need in any of the parent or child dialogs. In version 4 you can do that using the BotAccessors something on below lines
public static string CounterStateName { get; } = $"{nameof(BotAccessors)}.CounterState";
/// <summary>
/// Gets or sets the <see cref="IStatePropertyAccessor{T}"/> for CounterState.
/// </summary>
/// <value>
/// The accessor stores the turn count for the conversation.
/// </value>
public IStatePropertyAccessor<CounterState> CounterState { get; set; }

Serialise & deserialize CRM EntityCollection

I seem to recall in CRM 4, you could retrieve an EntityCollection to and from a file on disk. I would like to do this as part of writing both a backup mechanism, and a data transfer for a CRM Online instance.
However this does not seem to work correctly in CRM 2011 as the Attributes collection of each Entity contains a list of empty KeyValuePairOfStringObjects and the FormattedValues collection of each entity contains a list if empty KeyValuePairOfStringStrings.
Therefore the names and values of the entity's attributes have not been included in the serialization, however they definitely have values when viewed in the VS debugger.
Is there a way I can programatically store these collections to file so that they may be later deserialized and used to restore data to where they came from or to a parallel target instance eg for testing offline?
Here is my version of the serialization method proposed by #bigtv
private string Serialize(EntityCollection records)
{
string retVal = null;
using(var tw = new StringWriter())
using (var xw = new XmlTextWriter(tw))
{
var ser = new DataContractSerializer(typeof(EntityCollection));
ser.WriteObject(xw, records);
retVal = tw.ToString();
}
return retVal;
}
I had the exact same requirement to save the raw EntityCollection response back from a CRM FetchRequest. I got the same result as you from standard XmlSerializer, the trick is to use the same serializer that CRM is using under the hood.
Take a look at the DataContractSerializer class: MSDN reference is here
This is the helper class I then ended up writing:
class Serialiser
{
/// <summary>
/// The xml serialiser instance.
/// </summary>
private readonly DataContractSerializer dataContractSerialiser;
/// <summary>
/// Initializes a new instance of the <see cref="SerialiserService.Serialiser"/> class.
/// </summary>
/// <param name="typeToSerilaise">The type to serilaise.</param>
public Serialiser(Type typeToSerilaise)
{
this.dataContractSerialiser = new DataContractSerializer(typeToSerilaise);
}
/// <summary>
/// Serialises the specified candidate.
/// </summary>
/// <param name="candidate">The candidate.</param>
/// <returns>A serialised representaiton of the specified candidate.</returns>
public byte[] Serialise(object candidate)
{
byte[] output;
using (var ms = new MemoryStream())
{
this.dataContractSerialiser.WriteObject(ms, candidate);
var numberOfBytes = ms.Length;
output = new byte[numberOfBytes];
// Note: Only copy the exact stream length to avoid capturing trailing null bytes.
Array.Copy(ms.GetBuffer(), output, numberOfBytes);
}
return output;
}
/// <summary>
/// Deserialises the specified serialised instance.
/// </summary>
/// <param name="serialisedInstance">The serialised instance.</param>
/// <returns>A deserialised instance of the specified type.</returns>
public object Deserialise(byte[] serialisedInstance)
{
object output;
using (var ms = new MemoryStream(serialisedInstance))
using (var reader = XmlDictionaryReader.CreateTextReader(ms, new XmlDictionaryReaderQuotas()))
{
output = this.dataContractSerialiser.ReadObject(reader);
}
return output;
}
}
Usage:
new Serialiser(typeof(EntityCollection));
You can then read or write the byte[] to disk.

Multithreading Entity Framework: The connection was not closed. The connection's current state is connecting

So I have a windows service process that performs a workflow process. The back end uses Repository and UnitofWork Pattern and Unity on top of Entity Framework with the entities class generated from the edmx. I won't go into a whole lot of detail as its not necessary but basically there are 5 steps that the workflow goes through. A particular process might be at any stage at any point in time (in order of course). Step one just generates data for step two, which validates the data via a long running process to another server. Then step there generates a pdf with that data. For each stage we spawn a timer, however it is configurable to allow more than one timer to be spawned for each stage. Therein lays the problem. When I add a processor to a particular stage, it the following error randomly:
The connection was not closed. The connection's current state is connecting.
Reading up on this it seems obvious that this is happening because the context is trying to access the same entity from two threads. But this is where it is kind of throwing me for a loop. All of the information I can find on this states that we should be using a instance context per thread. Which as far as I can tell I am doing (see the code below). I am not using singleton pattern or statics or anything so I am not really sure why this is happening or how to avoid it. I have posted the relevant bits of my code below for your review.
The base repository:
public class BaseRepository
{
/// <summary>
/// Initializes a repository and registers with a <see cref="IUnitOfWork"/>
/// </summary>
/// <param name="unitOfWork"></param>
public BaseRepository(IUnitOfWork unitOfWork)
{
if (unitOfWork == null) throw new ArgumentException("unitofWork");
UnitOfWork = unitOfWork;
}
/// <summary>
/// Returns a <see cref="DbSet"/> of entities.
/// </summary>
/// <typeparam name="TEntity">Entity type the dbset needs to return.</typeparam>
/// <returns></returns>
protected virtual DbSet<TEntity> GetDbSet<TEntity>() where TEntity : class
{
return Context.Set<TEntity>();
}
/// <summary>
/// Sets the state of an entity.
/// </summary>
/// <param name="entity">object to set state.</param>
/// <param name="entityState"><see cref="EntityState"/></param>
protected virtual void SetEntityState(object entity, EntityState entityState)
{
Context.Entry(entity).State = entityState;
}
/// <summary>
/// Unit of work controlling this repository.
/// </summary>
protected IUnitOfWork UnitOfWork { get; set; }
/// <summary>
///
/// </summary>
/// <param name="entity"></param>
protected virtual void Attach(object entity)
{
if (Context.Entry(entity).State == EntityState.Detached)
Context.Entry(entity).State = EntityState.Modified;
}
protected virtual void Detach(object entity)
{
Context.Entry(entity).State = EntityState.Detached;
}
/// <summary>
/// Provides access to the ef context we are working with
/// </summary>
internal StatementAutoEntities Context
{
get
{
return (StatementAutoEntities)UnitOfWork;
}
}
}
StatementAutoEntities is the autogenerated EF class.
The repository implementation:
public class ProcessingQueueRepository : BaseRepository, IProcessingQueueRepository
{
/// <summary>
/// Creates a new repository and associated with a <see cref="IUnitOfWork"/>
/// </summary>
/// <param name="unitOfWork"></param>
public ProcessingQueueRepository(IUnitOfWork unitOfWork) : base(unitOfWork)
{
}
/// <summary>
/// Create a new <see cref="ProcessingQueue"/> entry in database
/// </summary>
/// <param name="Queue">
/// <see cref="ProcessingQueue"/>
/// </param>
public void Create(ProcessingQueue Queue)
{
GetDbSet<ProcessingQueue>().Add(Queue);
UnitOfWork.SaveChanges();
}
/// <summary>
/// Updates a <see cref="ProcessingQueue"/> entry in database
/// </summary>
/// <param name="queue">
/// <see cref="ProcessingQueue"/>
/// </param>
public void Update(ProcessingQueue queue)
{
//Attach(queue);
UnitOfWork.SaveChanges();
}
/// <summary>
/// Delete a <see cref="ProcessingQueue"/> entry in database
/// </summary>
/// <param name="Queue">
/// <see cref="ProcessingQueue"/>
/// </param>
public void Delete(ProcessingQueue Queue)
{
GetDbSet<ProcessingQueue>().Remove(Queue);
UnitOfWork.SaveChanges();
}
/// <summary>
/// Gets a <see cref="ProcessingQueue"/> by its unique Id
/// </summary>
/// <param name="id"></param>
/// <returns></returns>
public ProcessingQueue GetById(int id)
{
return (from e in Context.ProcessingQueue_SelectById(id) select e).FirstOrDefault();
}
/// <summary>
/// Gets a list of <see cref="ProcessingQueue"/> entries by status
/// </summary>
/// <param name="status"></param>
/// <returns></returns>
public IList<ProcessingQueue> GetByStatus(int status)
{
return (from e in Context.ProcessingQueue_SelectByStatus(status) select e).ToList();
}
/// <summary>
/// Gets a list of all <see cref="ProcessingQueue"/> entries
/// </summary>
/// <returns></returns>
public IList<ProcessingQueue> GetAll()
{
return (from e in Context.ProcessingQueue_Select() select e).ToList();
}
/// <summary>
/// Gets the next pending item id in the queue for a specific work
/// </summary>
/// <param name="serverId">Unique id of the server that will process the item in the queue</param>
/// <param name="workTypeId">type of <see cref="WorkType"/> we are looking for</param>
/// <param name="operationId">if defined only operations of the type indicated are considered.</param>
/// <returns>Next pending item in the queue for the work type or null if no pending work is found</returns>
public int GetNextPendingItemId(int serverId, int workTypeId, int? operationId)
{
var id = Context.ProcessingQueue_GetNextPending(serverId, workTypeId, operationId).SingleOrDefault();
return id.HasValue ? id.Value : -1;
}
/// <summary>
/// Returns a list of <see cref="ProcessingQueueStatus_dto"/>s objects with all
/// active entries in the queue
/// </summary>
/// <returns></returns>
public IList<ProcessingQueueStatus_dto> GetActiveStatusEntries()
{
return (from e in Context.ProcessingQueueStatus_Select() select e).ToList();
}
/// <summary>
/// Bumps an entry to the front of the queue
/// </summary>
/// <param name="processingQueueId"></param>
public void Bump(int processingQueueId)
{
Context.ProcessingQueue_Bump(processingQueueId);
}
}
We use Unity for dependency injection, some calling code for example:
#region Members
private readonly IProcessingQueueRepository _queueRepository;
#endregion
#region Constructors
/// <summary>Initializes ProcessingQueue services with repositories</summary>
/// <param name="queueRepository"><see cref="IProcessingQueueRepository"/></param>
public ProcessingQueueService(IProcessingQueueRepository queueRepository)
{
Check.Require(queueRepository != null, "processingQueueRepository is required");
_queueRepository = queueRepository;
}
#endregion
The code in the windows service that kicks off the timers is as follows:
_staWorkTypeConfigLock.EnterReadLock();
foreach (var timer in from operation in (from o in _staWorkTypeConfig.WorkOperations where o.UseQueueForExecution && o.AssignedProcessors > 0 select o)
let interval = operation.SpawnInternval < 30 ? 30 : operation.SpawnInternval
select new StaTimer
{
Interval = _runImmediate ? 5000 : interval*1000,
Operation = (ProcessingQueue.RequestedOperation) operation.OperationId
})
{
timer.Elapsed += ApxQueueProcessingOnElapsedInterval;
timer.Enabled = true;
Logger.DebugFormat("Queue processing for operations of type {0} will execute every {1} seconds", timer.Operation, timer.Interval/1000);
}
_staWorkTypeConfigLock.ExitReadLock();
StaTimer is just a wrapper on timer adding operation type. ApxQueueProcessingOnElapsedInterval then bascially just assigns work to the process based on the operation.
I will also add a bit of the ApxQueueProcessingOnElapsedInterval code where we are spawning tasks.
_staTasksLock.EnterWriteLock();
for (var x = 0; x < tasksNeeded; x++)
{
var t = new Task(obj => ProcessStaQueue((QueueProcessConfig) obj),
CreateQueueProcessConfig(true, operation), _cancellationToken);
_staTasks.Add(new Tuple<ProcessingQueue.RequestedOperation, DateTime, Task>(operation, DateTime.Now,t));
t.Start();
Thread.Sleep(300); //so there are less conflicts fighting for jobs in the queue table
}
_staTasksLock.ExitWriteLock();
Looks like your service, repository and context are supposed to live for the whole life time of your application but that is incorrect. You can have multiple timers triggered at the same time. That means multiple threads will use your service in parallel and they will execute the code of your service in their thread = context is shared among multiple threads => exception because context is not thread safe.
The only option is to use a new context instance for each operation you want to execute. You can for example change your classes to accept context factory instead of context and get a new context for each operation.
In case this helps anyone:
In my case, I did ensure that the non-thread-safe DbContext had a TransientLifetime (using Ninject), but it was still causing concurrency issues! Turns out that in some of my custom ActionFilters I used Dependency Injection to get access to the DbContext in the constructor, but ActionFilters have a lifetime that keeps them instantiated over multiple requests, so the context didn't get recreated.
I fixed it by manually resolving the dependency in the OnActionExecuting method instead of in the constructor so that it is a fresh instance every time.
In my case I was getting this problem because I forgot the await keyword before one of my DAL function calls. Putting await there resolved it.

How to add auto document for method & class & field in C# with ReSharper 5?

Visual Tomato AssistX provides a menu to automatically add method/class documents for the C++ functions.
Does ReSharper provide similar functions that I can use to add document for method/class?
I don't think Resharper does this for methods but if you want to insert file headers have a look at this post. If you want to add a method comment you can just place your cursor on an empty line above one of your method and insert 3 slashes which will insert a comment block for you to fill out.
public ActionResult Index(int page)
{
return View();
}
with /// inserted:
/// <summary>
///
/// </summary>
/// <param name="page"></param>
/// <returns></returns>
public ActionResult Index(int page)
{
return View();
}
I'm using GhostDoc for that.

Merge two objects to produce third using AutoMapper

I know it's AutoMapper and not AutoMerge(r), but...
I've started using AutoMapper and have a need to Map A -> B, and to add some properties from C so that B become a kind of flat composite of A + C.
Is this possible in AutoMapper of should I just use AutoMapper to do the heavy lifting then manually map on the extra properties?
Would this not work?
var mappedB = _mapper.Map<A,B>(aInstance);
_mapper.Map(instanceC,mappedB);
You can do this with the ValueInjecter
a.InjectFrom(b)
.InjectFrom(c)
.InjectFrom<SomeOtherMappingAlgorithmDefinedByYou>(dOrBOrWhateverObject);
I searched hard and long on this question and ended up implementing an extension method that merge's objects together.
I reference the steps on my blog http://twistyvortek.blogspot.com and here's the code:
using System;
namespace Domain.Models
{
public static class ExtendedMethods
{
/// <summary>
/// Merges two object instances together. The primary instance will retain all non-Null values, and the second will merge all properties that map to null properties the primary
/// </summary>
/// <typeparam name="T">Type Parameter of the merging objects. Both objects must be of the same type.</typeparam>
/// <param name="primary">The object that is receiving merge data (modified)</param>
/// <param name="secondary">The object supplying the merging properties. (unmodified)</param>
/// <returns>The primary object (modified)</returns>
public static T MergeWith<T>(this T primary, T secondary)
{
foreach (var pi in typeof (T).GetProperties())
{
var priValue = pi.GetGetMethod().Invoke(primary, null);
var secValue = pi.GetGetMethod().Invoke(secondary, null);
if (priValue == null || (pi.PropertyType.IsValueType && priValue == Activator.CreateInstance(pi.PropertyType)))
{
pi.GetSetMethod().Invoke(primary, new[] {secValue});
}
}
return primary;
}
}
}
Usage includes method chaining so you can merge multiple objects into one.
What I would do is use automapper to map part of the properties from your various sources into the same class of DTOs, etc. and then use this extension method to merge them together.
var Obj1 = Mapper.Map(Instance1);
var Obj2 = Mapper.Map(Instance2);
var Obj3 = Mapper.Map(Instance3);
var Obj4 = Mapper.Map(Instance4);
var finalMerge = Obj1.MergeWith(Obj2)
.MergeWith(Obj3)
.MergeWith(Obj4);
Hope this helps someone.
From what I remember with AutoMapper you have to define your mappings as one input to one output (maybe this has changed since - haven't utilized it for many a month).
If this is the case, maybe your mapping should be of KeyValuePair<A,C> (or some sort of object composing both A & C) => B
This way you can have one defined input parameter mapping to your outputted object
There is a nice example of merging multiple sources into a destination using autoMapper, here in Owain Wraggs' EMC Consulting Blog.
EDIT: To guard against the old "dead-link" syndrome, the essence of the code in Owain's blog is below.
/// <summary>
/// Helper class to assist in mapping multiple entities to one single
/// entity.
/// </summary>
/// <remarks>
/// Code courtesy of Owain Wraggs' EMC Consulting Blog
/// Ref:
/// http://consultingblogs.emc.com/owainwragg/archive/2010/12/22/automapper-mapping-from-multiple-objects.aspx
/// </remarks>
public static class EntityMapper
{
/// <summary>
/// Maps the specified sources to the specified destination type.
/// </summary>
/// <typeparam name="T">The type of the destination</typeparam>
/// <param name="sources">The sources.</param>
/// <returns></returns>
/// <example>
/// Retrieve the person, address and comment entities
/// and map them on to a person view model entity.
///
/// var personId = 23;
/// var person = _personTasks.GetPerson(personId);
/// var address = _personTasks.GetAddress(personId);
/// var comment = _personTasks.GetComment(personId);
///
/// var personViewModel = EntityMapper.Map<PersonViewModel>(person, address, comment);
/// </example>
public static T Map<T>(params object[] sources) where T : class
{
// If there are no sources just return the destination object
if (!sources.Any())
{
return default(T);
}
// Get the inital source and map it
var initialSource = sources[0];
var mappingResult = Map<T>(initialSource);
// Now map the remaining source objects
if (sources.Count() > 1)
{
Map(mappingResult, sources.Skip(1).ToArray());
}
// return the destination object
return mappingResult;
}
/// <summary>
/// Maps the specified sources to the specified destination.
/// </summary>
/// <param name="destination">The destination.</param>
/// <param name="sources">The sources.</param>
private static void Map(object destination, params object[] sources)
{
// If there are no sources just return the destination object
if (!sources.Any())
{
return;
}
// Get the destination type
var destinationType = destination.GetType();
// Itereate through all of the sources...
foreach (var source in sources)
{
// ... get the source type and map the source to the destination
var sourceType = source.GetType();
Mapper.Map(source, destination, sourceType, destinationType);
}
}
/// <summary>
/// Maps the specified source to the destination.
/// </summary>
/// <typeparam name="T">type of teh destination</typeparam>
/// <param name="source">The source.</param>
/// <returns></returns>
private static T Map<T>(object source) where T : class
{
// Get thr source and destination types
var destinationType = typeof(T);
var sourceType = source.GetType();
// Get the destination using AutoMapper's Map
var mappingResult = Mapper.Map(source, sourceType, destinationType);
// Return the destination
return mappingResult as T;
}
}
The resultant calling code is nice an succinct.
public ActionResult Index()
{
// Retrieve the person, address and comment entities and
// map them on to a person view model entity
var personId = 23;
var person = _personTasks.GetPerson(personId);
var address = _personTasks.GetAddress(personId);
var comment = _personTasks.GetComment(personId);
var personViewModel = EntityMapper.Map<PersonViewModel>(person, address, comment);
return this.View(personViewModel);
}

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