I want to have 3 different functions all called "AddField" where each function has different parameters. Based on the parameters, the language will know which function to call. Delphi has this concept if you mark the function as "overload".
void addField(int tableID, fieldID) {
addfield(tableID, fieldID, 0, 0)
}
void addField(int tableID, fieldID, groupID) {
addfield(tableID, fieldID, groupID, 0)
}
void addField(int tableID, fieldID, groupID, size) {
item = FieldItem();
item.tableID = tableID;
item.fieldID = fieldID;
item.groupID = groupID;
item.size = size;
fieldlist.add(item);
}
and they can be used this way...
void addClientFields(){
addfield(tblIDClient, fldIDName, grpContact, 30);
addfield(tblIDClient, fldIDActive);
addfield(tblIDClient, fldIDDate, grpSettings);
}
Dart doesn't have Method overloading. You can make method with different name or use optional paramater with default value.
void addField(int tableID, fieldID, [int groupID = 0, int size = 0]) {
item = FieldItem();
item.tableID = tableID;
item.fieldID = fieldID;
item.groupID = groupID;
item.size = size;
fieldlist.add(item);
}
Related
I'm upgrading some legacy to target Android Q, and of course this code stop working:
String[] PROJECTION_BUCKET = {MediaStore.Images.ImageColumns.BUCKET_ID,
MediaStore.Images.ImageColumns.BUCKET_DISPLAY_NAME,
MediaStore.Images.ImageColumns.DATE_TAKEN,
MediaStore.Images.ImageColumns.DATA,
"COUNT(" + MediaStore.Images.ImageColumns._ID + ") AS COUNT",
MediaStore.Files.FileColumns.MEDIA_TYPE,
MediaStore.MediaColumns._ID};
String BUCKET_GROUP_BY = " 1) and " + BUCKET_WHERE.toString() + " GROUP BY 1,(2";
cur = context.getContentResolver().query(images, PROJECTION_BUCKET,
BUCKET_GROUP_BY, null, BUCKET_ORDER_BY);
android.database.sqlite.SQLiteException: near "GROUP": syntax error (code 1 SQLITE_ERROR[1])
Here it supposed to obtain list of images with album name, date, count of pictures - one image for each album, so we can create album picker screen without querying all pictures and loop through it to create albums.
Is it possible to group query results with contentResolver since SQL queries stoped work?
(I know that ImageColumns.DATA and "COUNT() AS COUNT" are deprecated too, but this is a question about GROUP BY)
(There is a way to query albums and separately query photo, to obtain photo uri for album cover, but i want to avoid overheads)
Unfortunately Group By is no longer supported in Android 10 and above, neither any aggregated functions such as COUNT. This is by design and there is no workaround.
The solution is what you are actually trying to avoid, which is to query, iterate, and get metrics.
To get you started you can use the next snipped, which will resolve the buckets (albums), and the amount of records in each one.
I haven't added code to resolve the thumbnails, but is easy. You must perform a query for each bucket Id from all the Album instances, and use the image from the first record.
public final class AlbumQuery
{
#NonNull
public static HashMap<String, AlbumQuery.Album> get(#NonNull final Context context)
{
final HashMap<String, AlbumQuery.Album> output = new HashMap<>();
final Uri contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
final String[] projection = {MediaStore.Images.Media.BUCKET_DISPLAY_NAME, MediaStore.Images.Media.BUCKET_ID};
try (final Cursor cursor = context.getContentResolver().query(contentUri, projection, null, null, null))
{
if ((cursor != null) && (cursor.moveToFirst() == true))
{
final int columnBucketName = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.BUCKET_DISPLAY_NAME);
final int columnBucketId = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.BUCKET_ID);
do
{
final String bucketId = cursor.getString(columnBucketId);
final String bucketName = cursor.getString(columnBucketName);
if (output.containsKey(bucketId) == false)
{
final int count = AlbumQuery.getCount(context, contentUri, bucketId);
final AlbumQuery.Album album = new AlbumQuery.Album(bucketId, bucketName, count);
output.put(bucketId, album);
}
} while (cursor.moveToNext());
}
}
return output;
}
private static int getCount(#NonNull final Context context, #NonNull final Uri contentUri, #NonNull final String bucketId)
{
try (final Cursor cursor = context.getContentResolver().query(contentUri,
null, MediaStore.Images.Media.BUCKET_ID + "=?", new String[]{bucketId}, null))
{
return ((cursor == null) || (cursor.moveToFirst() == false)) ? 0 : cursor.getCount();
}
}
public static final class Album
{
#NonNull
public final String buckedId;
#NonNull
public final String bucketName;
public final int count;
Album(#NonNull final String bucketId, #NonNull final String bucketName, final int count)
{
this.buckedId = bucketId;
this.bucketName = bucketName;
this.count = count;
}
}
}
This is a more efficient(not perfect) way to do that.
I am doing it for videos, but doing so is the same for images to. just change MediaStore.Video.Media.X to MediaStore.Images.Media.X
public class QUtils {
/*created by Nasib June 6, 2020*/
#RequiresApi(api = Build.VERSION_CODES.Q)
public static ArrayList<FolderHolder> loadListOfFolders(Context context) {
ArrayList<FolderHolder> allFolders = new ArrayList<>();//list that we need
HashMap<Long, String> folders = new HashMap<>(); //hashmap to track(no duplicates) folders by using their ids
String[] projection = {MediaStore.Video.Media._ID,
MediaStore.Video.Media.BUCKET_ID,
MediaStore.Video.Media.BUCKET_DISPLAY_NAME,
MediaStore.Video.Media.DATE_ADDED};
ContentResolver CR = context.getContentResolver();
Uri root = MediaStore.Video.Media.getContentUri(MediaStore.VOLUME_EXTERNAL);
Cursor c = CR.query(root, projection, null, null, MediaStore.Video.Media.DATE_ADDED + " desc");
if (c != null && c.moveToFirst()) {
int folderIdIndex = c.getColumnIndexOrThrow(MediaStore.Video.Media.BUCKET_ID);
int folderNameIndex = c.getColumnIndexOrThrow(MediaStore.Video.Media.BUCKET_DISPLAY_NAME);
int thumbIdIndex = c.getColumnIndexOrThrow(MediaStore.Video.Media._ID);
int dateAddedIndex = c.getColumnIndexOrThrow(MediaStore.Video.Media.DATE_ADDED);
do {
Long folderId = c.getLong(folderIdIndex);
if (folders.containsKey(folderId) == false) { //proceed only if the folder data has not been inserted already :)
long thumbId = c.getLong(thumbIdIndex);
String folderName = c.getString(folderNameIndex);
String dateAdded = c.getString(dateAddedIndex);
Uri thumbPath = ContentUris.withAppendedId(MediaStore.Video.Media.EXTERNAL_CONTENT_URI, thumbId);
folders.put(folderId, folderName);
allFolders.add(new FolderHolder(String.valueOf(thumbPath), folderName, dateAdded));
}
} while (c.moveToNext());
c.close(); //close cursor
folders.clear(); //clear the hashmap becuase it's no more useful
}
return allFolders;
}
}
FolderHolder model class
public class FolderHolder {
private String folderName;
public long dateAdded;
private String thumbnailPath;
public long folderId;
public void setPath(String thumbnailPath) {
this.thumbnailPath = thumbnailPath;
}
public String getthumbnailPath() {
return thumbnailPath;
}
public FolderHolder(long folderId, String thumbnailPath, String folderName, long dateAdded) {
this.folderId = folderId;
this.folderName = folderName;
this.thumbnailPath = thumbnailPath;
this.dateAdded = dateAdded;
}
public String getFolderName() {
return folderName;
}
}
GROUP_BY supporting in case of using Bundle:
val bundle = Bundle().apply {
putString(
ContentResolver.QUERY_ARG_SQL_SORT_ORDER,
"${MediaStore.MediaColumns.DATE_MODIFIED} DESC"
)
putString(
ContentResolver.QUERY_ARG_SQL_GROUP_BY,
MediaStore.Images.ImageColumns.BUCKET_ID
)
}
contentResolver.query(
uri,
arrayOf(
MediaStore.Images.ImageColumns.BUCKET_ID,
MediaStore.Images.ImageColumns.BUCKET_DISPLAY_NAME,
MediaStore.Images.ImageColumns.DATE_TAKEN,
MediaStore.Images.ImageColumns.DATA
),
bundle,
null
)
public class Branch
{
[Sortable(OrderBy = "BranchId")]
public long BranchId { get; set; }
public string Name { get; set; }
public string Code { get; set; }
public string Type { get; set; }
}
this is my Model class and I also create a custom attribute
public class SortableAttribute : Attribute
{
public string OrderBy { get; set; }
}
now i create a pagination with orderby descending but this code not working
public static async Task<IPagedList<T>> ToPagedListAsync<T>(this IQueryable<T> source,
GeneralPagingRequest pagingRequest, int indexFrom = 0,
CancellationToken cancellationToken = default(CancellationToken))
{
if (indexFrom > pagingRequest.PageNumber)
{
throw new ArgumentException(
$"indexFrom: {indexFrom} > pageNumber: {pagingRequest.PageNumber}, must indexFrom <= pageNumber");
}
var count = await source.CountAsync(cancellationToken).ConfigureAwait(false);
var items = source.Skip(((pagingRequest.PageNumber - 1) - indexFrom) * pagingRequest.PageSize)
.Take(pagingRequest.PageSize);
var props = typeof(T).GetProperties();
PropertyInfo orderByProperty;
orderByProperty =
props.FirstOrDefault(x=>x.GetCustomAttributes(typeof(SortableAttribute), true).Length != 0);
if (pagingRequest.OrderBy == "desc")
{
items = items.OrderBy(x => orderByProperty.GetValue(x));
}
else
{
items = items.OrderBy(x => orderByProperty.GetValue(x));
}
var result = await items.ToListAsync(cancellationToken).ConfigureAwait(false);
var pagedList = new PagedList<T>
{
PageNumber = pagingRequest.PageNumber,
PageSize = pagingRequest.PageSize,
IndexFrom = indexFrom,
TotalCount = count,
Items = result,
TotalPages = (int) Math.Ceiling(count / (double) pagingRequest.PageSize)
};
return pagedList;
}
but the result variable create exception
.OrderBy() requires a delegate that would tell it HOW to select a key, not the key value itself. So you are looking at some meta-programming here.
Naturally, you will look at building a dynamic LINQ Expression tree that will fetch a property for you:
// your code up above
PropertyInfo orderByProperty = props.FirstOrDefault(x => x.GetCustomAttributes(typeof(SortableAttribute), true).Length != 0);
var p = Expression.Parameter(typeof(T), "x"); // you define your delegate parameter here
var accessor = Expression.Property(p, orderByProperty.GetMethod); // this basically becomes your `x => x.BranchId` construct
var predicate = Expression.Lambda(accessor, p).Compile(); // here's our problem: as we don't know resulting type at compile time we can't go `Expression.Lambda<T, long>(accessor, p)` here
if (pagingRequest.OrderBy == "desc")
{
items = items.OrderByDescending(x => predicate(x)); // passing a Delegate here will not work as OrderBy requires Func<T, TKey>
}
else
{
items = items.OrderBy(x => predicate(x)); // passing a Delegate here will not work as OrderBy requires Func<T, TKey>
}
var result = await items.ToListAsync(cancellationToken).ConfigureAwait(false);
// your code down below
Problem with the above code - you don't know TKey upfront. Therefore we will have to go a level deeper and build the whole items.OrderBy(x => x.BranchId) expression dynamically. The biggest leap of faith here will be the fact the OrderBy is an extension method and it actually resides on IQueryable type. After you've got the generic method reference, you will need to build a specific delegate type when you know your property type. So your method becomes something like this:
public static class ExtToPagedListAsync
{
private static readonly MethodInfo OrderByMethod = typeof(Queryable).GetMethods().Single(method => method.Name == "OrderBy" && method.GetParameters().Length == 2); // you need your method reference, might as well find it once
private static readonly MethodInfo OrderByDescendingMethod = typeof(Queryable).GetMethods().Single(method => method.Name == "OrderByDescending" && method.GetParameters().Length == 2); // you need your method reference, might as well find it once
public static async Task<IPagedList<T>> ToPagedListAsync<T>(this IQueryable<T> source, GeneralPagingRequest pagingRequest, int indexFrom = 0, CancellationToken cancellationToken = default(CancellationToken))
{
if (indexFrom > pagingRequest.PageNumber)
{
throw new ArgumentException(
$"indexFrom: {indexFrom} > pageNumber: {pagingRequest.PageNumber}, must indexFrom <= pageNumber");
}
var count = await source.CountAsync(cancellationToken).ConfigureAwait(false);
var items = source.Skip(((pagingRequest.PageNumber - 1) - indexFrom) * pagingRequest.PageSize)
.Take(pagingRequest.PageSize);
var props = typeof(T).GetProperties();
PropertyInfo orderByProperty = props.FirstOrDefault(x => x.GetCustomAttributes(typeof(SortableAttribute), true).Length != 0);
var p = Expression.Parameter(typeof(T), "x");
var accessor = Expression.Property(p, orderByProperty.GetMethod);
var predicate = Expression.Lambda(accessor, p); // notice, we're not yet compiling the predicate. we still want an Expression here
// grab the correct method depending on your condition
MethodInfo genericMethod = (pagingRequest.OrderBy == "desc") ? OrderByDescendingMethod.MakeGenericMethod(typeof(T), orderByProperty.PropertyType)
:OrderByMethod.MakeGenericMethod(typeof(T), orderByProperty.PropertyType);
object ret = genericMethod.Invoke(null, new object[] { items, predicate });
items = (IQueryable<T>)ret; // finally cast it back to Queryable with your known T
var result = await items.ToListAsync(cancellationToken).ConfigureAwait(false);
var pagedList = new PagedList<T>
{
PageNumber = pagingRequest.PageNumber,
PageSize = pagingRequest.PageSize,
IndexFrom = indexFrom,
TotalCount = count,
Items = result,
TotalPages = (int)Math.Ceiling(count / (double)pagingRequest.PageSize)
};
return pagedList;
}
}
I must disclose I did get some inspiration from this answer here, so do check it out for further reading.
I have a master report with 4 subreports in its details section. I want to display the page number range (for example 1- 2) of all the subreports in the Master report title section. I tried using subreport return value but it works only when I have 1 subreport not if there are more than 1 subreport
Here is the solution
Step1 : Create variables of any type inside each of the SubReport and the set the calculation, Increment Type and Reset Type to None. No need to specify the Expression as well Initial Value Expression
Step 2 : Create variables of String type inside the Master Report to hold the value of page number (eg. 1-2) and set the Calculation as System.
Step 3 : Add the variables created in Step2 on the Master Report Title section and set the evaluation time as Report.
Step 4 : Create scriptlet and set the page number in that
public class PageScriptlet extends JRDefaultScriptlet {
private static int mgmtReportPages;
private static int balanceSheetReportPages;
private static int incomeStmtReportPages;
private static int addInfoReportPages;
private static final String MGMT_REPORT_PAGENUM = "mgmtReportPageNum";
private static final String INCOME_STMT_PAGENUM = "incomeStmtPageNum";
private static final String BALANCE_SHEET_PAGENUM = "balanceSheetPageNum";
private static final String ADDINFO_PAGENUM = "addInfoPageNum";
private static final String MGMT_REPORT_INDEX = "mgmtReportIndex";
private static final String INCOMESTMT_INDEX = "incomeStmtIndex";
private static final String BALANCESHEET_INDEX = "balanceSheetIndex";
private static final String NOTES_INDEX = "notesIndex";
private static final String SIGNATURE_INDEX = "signatureIndex";
private static Integer firstPage = 2;
public PageScriptlet() {
super ();
}
#Override
public void afterPageInit() throws JRScriptletException{
Map<String, JRFillVariable> variablesMap = this.variablesMap;
if(variablesMap.containsKey(MGMT_REPORT_INDEX)){
Integer lastPage = mgmtReportPages+1;
String index = null;
if(firstPage == lastPage){
index = String.valueOf(firstPage);
}else{
index = String.valueOf(firstPage)+"-"+String.valueOf(lastPage);
}
this.setVariableValue(MGMT_REPORT_INDEX, index);
}
if(variablesMap.containsKey(INCOMESTMT_INDEX)){
Integer firstPage = mgmtReportPages + 2;
Integer lastPage = incomeStmtReportPages;
String index = null;
if(firstPage == lastPage){
index = String.valueOf(firstPage);
}else{
index = String.valueOf(firstPage)+"-"+String.valueOf(lastPage);
}
this.setVariableValue(INCOMESTMT_INDEX, index);
}
if(variablesMap.containsKey(BALANCESHEET_INDEX)){
Integer firstPage = incomeStmtReportPages+1;
Integer lastPage = balanceSheetReportPages;
String index = null;
if(firstPage == lastPage){
index = String.valueOf(firstPage);
}else{
index = String.valueOf(firstPage)+"-"+String.valueOf(lastPage);
}
this.setVariableValue(BALANCESHEET_INDEX, index);
}
if(variablesMap.containsKey(NOTES_INDEX)){
Integer firstPage = balanceSheetReportPages + 1;
Integer lastPage = addInfoReportPages;
String index = null;
if(firstPage == lastPage){
index = String.valueOf(firstPage);
}else{
index = String.valueOf(firstPage)+"-"+String.valueOf(lastPage);
}
this.setVariableValue(NOTES_INDEX, index);
}
if(variablesMap.containsKey(SIGNATURE_INDEX)){
Integer lastPage = addInfoReportPages;
String index = String.valueOf(lastPage);
this.setVariableValue(SIGNATURE_INDEX, index);
}
}
#Override
public void beforePageInit() throws JRScriptletException{
Map<String, JRFillVariable> variablesMap = this.variablesMap;
Integer pageNumber = (Integer)this.getVariableValue("PAGE_NUMBER");
if(variablesMap.containsKey(MGMT_REPORT_PAGENUM)){
mgmtReportPages = pageNumber == null ? 1 : pageNumber + 1;
}
if(variablesMap.containsKey(INCOME_STMT_PAGENUM)){
incomeStmtReportPages = pageNumber == null ? mgmtReportPages + 2 : incomeStmtReportPages + 1;
}
if(variablesMap.containsKey(BALANCE_SHEET_PAGENUM)){
balanceSheetReportPages = pageNumber == null ? incomeStmtReportPages + 1 : balanceSheetReportPages + 1;
}
if(variablesMap.containsKey(ADDINFO_PAGENUM)){
addInfoReportPages = pageNumber == null ? balanceSheetReportPages+1 : addInfoReportPages + 1;
}
}
}
edittext1.addTextChangedListener(new TextWatcher() {
#Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
selStart = edittext1.getSelectionStart();
selEnd= edittext1.getSelectionEnd();
lengthBefore = edittext1.getText().toString().length();
}
#Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
#Override
public void afterTextChanged(Editable s) {
int lengthAfter = edittext1.getText().toString().length() - lengthBefore;
if(!(lengthAfter < 0))
{
String codedBefore = editTextCoded.getText().toString().substring(0, selStart);
String codedAfter;
if(selEnd>1) {
codedAfter = editTextCoded.getText().toString().substring(selEnd);
}
else
{
codedAfter = "";
}
editTextCoded.setText(codedBefore);
//Zakodowanie nowego
String toBeCoded = edittext1.getText().toString().substring(selStart, selEnd+ lengthAfter);
for(int i=0; i<toBeCoded.length(); i++)
{
newChar = toBeCoded.charAt(i);
editTextCoded.setText(editTextCoded.getText().toString() + Character.toString(newChar));
}
//Dopisanie końcówki tłumaczenia
editTextCoded.setText(editTextCoded.getText().toString() + codedAfter);
}
else
{
String codedBefore = editTextCoded.getText().toString().substring(0, selStart + lengthAfter);
String codedAfter = editTextCoded.getText().toString().substring(selStart, editTextCoded.length());
editTextCoded.setText(codedBefore + codedAfter);
}
}
});
after this operation editTextCoded and edittext1 should show the same text, yet when I copy part of the text, then select another (smaller) part and paste it replacing the selected part, the text in editTextCoded and edittext1 differs.
Anyone could please help me? I have no ideas left what to do with it.
I have a Hot stream of events coming of following type:
Event
{
string name;
int state ; // its 1 or 2 ie active or unactive
}
there is a function which provides parent name of given name - string GetParent(string name)
I need to buffer event per parent for 2 minutes, if during this 2 minute , i recv any event for child with state =2 for a given parent , this buffer should cancel and should output 0 otherwise i get the count of the events recvd .
I know I have to use GroupBy to partition, and then buffer and then count but i am unable to think of a way by which i create Buffer which is unique per parent, i though of using Distinct but this doesnt solve the problem, for i only dont want to create buffer till the parent is active (as once the parent's buffer gets cancelled or 2 minutes is over, the parent buffer can be created again)
So I understand I need to create a custom buffer which checks the condition for creating buffer, but how do i do this via reactive extensions.
Any help will be greatly appreciated.
regards
Thanks Brandon for your help. This is the main program I am using for testing. Its not working.As I am new to reactive extension problem can be in the way i am testing
namespace TestReactive
{
class Program
{
static int abc = 1;
static void Main(string[] args)
{
Subject<AEvent> memberAdded = new Subject<AEvent>();
//ISubject<AEvent, AEvent> syncedSubject = new ISubject<AEvent, AEvent>();
var timer = new Timer { Interval = 5 };
timer.Enabled = true;
timer.Elapsed += (sender, e) => MyElapsedMethod(sender, e, memberAdded);
var bc = memberAdded.Subscribe();
var cdc = memberAdded.GroupBy(e => e.parent)
.SelectMany(parentGroup =>
{
var children = parentGroup.Publish().RefCount();
var inactiveChild = children.SkipWhile(c => c.state != 2).Take(1).Select(c => 0);
var timer1 = Observable.Timer(TimeSpan.FromSeconds(1));
var activeCount = children.TakeUntil(timer1).Count();
return Observable.Amb(activeCount, inactiveChild)
.Select(count => new { ParentName = parentGroup.Key, Count = count });
});
Observable.ForEachAsync(cdc, x => WriteMe("Dum Dum " + x.ParentName+x.Count));
// group.Dump("Dum");
Console.ReadKey();
}
static void WriteMe(string sb)
{
Console.WriteLine(sb);
}
static void MyElapsedMethod(object sender, ElapsedEventArgs e, Subject<AEvent> s)
{
AEvent ab = HelperMethods.GetAlarm();
Console.WriteLine(abc + " p =" + ab.parent + ", c = " + ab.name + " ,s = " + ab.state);
s.OnNext(ab);
}
}
}
public static AEvent GetAlarm()
{
if (gp> 4)
gp = 1;
if (p > 4)
p = 1;
if (c > 4)
c = 1;
AEvent a = new AEvent();
a.parent = "P" + gp + p;
a.name = "C" + gp + p + c;
if (containedKeys.ContainsKey(a.name))
{
a.state = containedKeys[a.name];
if (a.state == 1)
containedKeys[a.name] = 2;
else
containedKeys[a.name] = 1;
}
else
{
containedKeys.TryAdd(a.name, 1);
}
gp++; p++; c++;
return a;
}
So this method , generates a event for Parent at each tick. It generates event for parent P11,P22,P33,P44 with State =1 and then followed by events for Parent P11,P22,P33,P44 with State =2
I am using Observable.ForEach to print the result, I see its being called 4 times and after that its nothing, its like cancellation of group is not happening
Assuming that a two minute buffer for each group should open as soon as the first event for that group is seen, and close after two minutes or a zero state is seen, then I think the following works:
public static IObservable<EventCount> EventCountByParent(
this IObservable<Event> source, IScheduler scheduler)
{
return Observable.Create<EventCount>(observer => source.GroupByUntil(
evt => GetParent(evt.Name),
evt => evt,
group =>
#group.Where(evt => evt.State == 2)
.Merge(Observable.Timer(
TimeSpan.FromMinutes(2), scheduler).Select(_ => Event.Null)))
.SelectMany(
go =>
go.Aggregate(0, (acc, evt) => (evt.State == 2 ? 0 : acc + 1))
.Select(count => new EventCount(go.Key, count))).Subscribe(observer));
}
With EventCount (implementing equality overrides for testing) as:
public class EventCount
{
private readonly string _name;
private readonly int _count;
public EventCount(string name, int count)
{
_name = name;
_count = count;
}
public string Name { get { return _name; } }
public int Count { get { return _count; } }
public override string ToString()
{
return string.Format("Name: {0}, Count: {1}", _name, _count);
}
protected bool Equals(EventCount other)
{
return string.Equals(_name, other._name) && _count == other._count;
}
public override bool Equals(object obj)
{
if (ReferenceEquals(null, obj)) return false;
if (ReferenceEquals(this, obj)) return true;
if (obj.GetType() != this.GetType()) return false;
return Equals((EventCount) obj);
}
public override int GetHashCode()
{
unchecked
{
return ((_name != null ? _name.GetHashCode() : 0)*397) ^ _count;
}
}
}
And Event as:
public class Event
{
public static Event Null = new Event(string.Empty, 0);
private readonly string _name;
private readonly int _state;
public Event(string name, int state)
{
_name = name;
_state = state;
}
public string Name { get { return _name; } }
public int State { get { return _state; } }
}
I did a quick (i.e. not exhaustive) test with Rx-Testing:
public class EventCountByParentTests : ReactiveTest
{
private readonly TestScheduler _testScheduler;
public EventCountByParentTests()
{
_testScheduler = new TestScheduler();
}
[Fact]
public void IsCorrect()
{
var source = _testScheduler.CreateHotObservable(
OnNext(TimeSpan.FromSeconds(10).Ticks, new Event("A", 1)),
OnNext(TimeSpan.FromSeconds(20).Ticks, new Event("B", 1)),
OnNext(TimeSpan.FromSeconds(30).Ticks, new Event("A", 1)),
OnNext(TimeSpan.FromSeconds(40).Ticks, new Event("B", 1)),
OnNext(TimeSpan.FromSeconds(50).Ticks, new Event("A", 1)),
OnNext(TimeSpan.FromSeconds(60).Ticks, new Event("B", 2)),
OnNext(TimeSpan.FromSeconds(70).Ticks, new Event("A", 1)),
OnNext(TimeSpan.FromSeconds(140).Ticks, new Event("A", 1)),
OnNext(TimeSpan.FromSeconds(150).Ticks, new Event("A", 1)));
var results = _testScheduler.CreateObserver<EventCount>();
var sut = source.EventCountByParent(_testScheduler).Subscribe(results);
_testScheduler.Start();
results.Messages.AssertEqual(
OnNext(TimeSpan.FromSeconds(60).Ticks, new EventCount("B", 0)),
OnNext(TimeSpan.FromSeconds(130).Ticks, new EventCount("A", 4)),
OnNext(TimeSpan.FromSeconds(260).Ticks, new EventCount("A", 2)));
}
}
something like....
source.GroupBy(e => GetParent(e.name))
.SelectMany(parentGroup =>
{
var children = parentGroup.Publish().RefCount();
var inactiveChild = children.SkipWhile(c => c.state != 2).Take(1).Select(c => 0);
var timer = Observable.Timer(TimeSpan.FromMinutes(2));
var activeCount = children.TakeUntil(timer).Count();
return Observable.Amb(activeCount, inactiveChild)
.Select(count => new { ParentName = parentGroup.Key, Count = count };
});
This will give you a sequence of { ParentName, Count } objects.