I'm doing a React/Redux project, and need to implement a virtualized/infinite-loading list. react-virtualized seems intended to do the job, but even after reading all of the available docs and reading a number of StackOverflow posts, I haven't been able to get it working or found a clear explanation of the mechanics of how the components actually work.
The primary examples I've looked at are:
https://github.com/bvaughn/react-virtualized/blob/master/docs/creatingAnInfiniteLoadingList.md
https://github.com/bvaughn/react-virtualized/blob/master/docs/InfiniteLoader.md#examples
The primary issues I'm running into are:
It's very unclear how the loader is triggered to make a call to loadMoreRows() in the initial load/render case. Typical scenario is that we'd design the component to initialize itself with data by calling loadMoreRows() when it's initially rendered. The config values necessary to make this happen aren't obvious.
It's not clear whether the rowCount property is intended to represent the current state of loaded rows (the number of rows in a block/page of data), or the total count of the full set of row data. And, in either case, these can't be known in advance of making the initial AJAX load call, so what's the intention for setting the initial value of rowCount?
I've tried putting the code from various examples into my project, but I never see the loadMoreRows call being made. I think what's need is a fleshed-out example that demonstrates a very typical use case of a) initially rendering an empty List, which then triggers an initial data load call; b) updating the rowCount property, and when/where to do this; c) managing the currently-loaded data set representing the current block/page of data.
Any pointers would be much appreciated.
loadMoreRows is passed as a prop to InfiniteLoader (you can see that in the examples). It isn't meant to be called manually, it is used internally by InfiniteLoader and List, and is called automatically when scrolling down.
rowCount can have both of those behaviours. Your API could tell how many items there are without fetching them all, or it could not. rowCount simply tells List how many rows there are.
So for example, let's say we have 100 stores, and our first fetch gives us the first 10. That same response should say if there are more stores to be fetched still or not. Another fetch could tell us there are 100 stores total.
With this, we could use the total of 100 as rowCount (by querying the total number of stores, without fetching them all) OR we could use 10 + 1 as rowCount, as the first fetch told us there were still more stores to be loaded yet.
What would this mean?
If we have the first 10 stores loaded, and use rowCount = 100, InfiniteLoader would display 100 rows, but only the first 10 would have any content at all, with the rest of them showing the "loading" row placeholder component. And as that 'not yet loaded' rows appear as you scroll down, InfiniteLoader would call the loadMoreRows function to, well, load more rows.
In the other hand, if we had used rowCount = 10 + 1, InfiniteLoader would display only 11 rows, with only the last one being the "loading" row placeholder component. And when loadMoreRows is called, rowCount would be items.length + 1 === 20 + 1.
Summing up
loadMoreRows isn't meant to be called manually. It is called automatically by InfiniteLoader when a row that isn't loaded is being shown in the viewport. So initially rowCount could be just 1, no row would be loaded, and loadMoreRows would be called.
rowCount could either be currentItems.length + (moreToBeLoaded ? 1 : 0) or totalItems. The difference being what is shown to the user, either "Oops, end of what is loaded, wait some for more" or "Look, these are all the items there is, but haven't been loaded yet, wait some for them to load"
I have the following django method:
def setCurrentSong(request, player):
try:
newCurrentSong = ActivePlaylistEntry.objects.get(
song__player_lib_song_id=request.POST['lib_id'],
song__player=player,
state=u'QE')
except ObjectDoesNotExist:
toReturn = HttpResponseNotFound()
toReturn[MISSING_RESOURCE_HEADER] = 'song'
return toReturn
try:
currentSong = ActivePlaylistEntry.objects.get(song__player=player, state=u'PL')
currentSong.state=u'FN'
currentSong.save()
except ObjectDoesNotExist:
pass
except MultipleObjectsReturned:
#This is bad. It means that
#this function isn't getting executed atomically like we hoped it would be
#I think we may actually need a mutex to protect this critial section :(
ActivePlaylistEntry.objects.filter(song__player=player, state=u'PL').update(state=u'FN')
newCurrentSong.state = u'PL'
newCurrentSong.save()
PlaylistEntryTimePlayed(playlist_entry=newCurrentSong).save()
return HttpResponse("Song changed")
Essentially, I want it to be so that for a given player, there is only one ActivePlaylistEntry that has a 'PL' (playing) state at any given time. However, I have actually experienced cases where, as a result of quickly calling this method twice in a row, I get two songs for the same player with a state of 'PL'. This is bad as I have other application logic that relies on the fact that a player only has one playing song at any given time (plus semantically it doesn't make sense to be playing two different songs at the same time on the same player). Is there a way for me to do this update atomically? Just running the method as a transaction with the on_commit_success decorator doesn't seem to work. Is there like a way to lock the table for all songs belonging to a particular player? I was thinking of adding a lock column to my model (boolean field) and either just spinning on it or pausing the thread for a few milliseconds and checking again but these feel super hackish and dirty. I was also thinking about creating a stored procedure but that's not really database independent.
Locking queries were added in 1.4.
with transaction.commit_manually():
ActivePlayListEntry.objects.select_for_update().filter(...)
aple = ActivePlayListEntry.objects.get(...)
aple.state = ...
transaction.commit()
But you should consider refactoring so that a separate table with a ForeignKey is used to indicate the "active" song.
How to do a basic loop through different properties for a fixed set of controllers? Loop controller runs a set group a certain number of times, does not use properties though.
I can do modules, and set the values to properties for multi thread group usage, but how to pass the next iteration of the property, and run the loop again?
property x
do module (points to controllers)
next property
Say I have a list of 44 characters, and I want to loop through those characters in a ${name} while I'm doing a test. I'd very much not like to build 44 sets of controllers for one character change.
Please Note I cannot add extra files to my computer. It has to work via the stock available controllers. I'm using Jmeter 2.4 r961953
Thanks
I will elaborate slightly more about the BeanShell method. My assumption is that you'd like to do it within one User Thread, if so my proposal would be:
Create a Loop Controller.
Logic Controller->Loop Controller
Inside Loop Controller add following entries:
Config Element -> Counter
Preprocessors -> BeanShell preprocessor
Sampler -> yourSampler
The Counter element will be used as an index that will be used to choose valid value from our array, hence we need to specify a Reference Name for the Counter - let's say that it will be loopCounter.
Now we have to switch to BeanShell preprocessor and define the array of values. A great thing is that we have vars variable available and it gives us CRUD access to variables used in the scenario:
String[] varArray = {"Value1", "Value2"};
idx = Integer.parseInt(vars.get("loopCounter"))-1;
vars.put("myVariable", varArray[idx]);
And for the final step, inside mySampler we can use a variable in a regular JMeter way : ${myVariable}
JMeter API can be very helpfull if you want a more sophisticated solution.
There are a handful of different ways to loop through different values without adding external files:
Use beanshell controller, and write javascript to set your variable
Use a counter to increment by one
Use User Parameters
You can set it up so each loop gets a different value.
Check out the various configuration controllers to find one that works best for you.
EDIT:
I meant user parameters, not user define variables.
User Parameter
You'd need one row per variable with 44 columns. Sorry for the confusion.
User Parameter Structure
test plan
- Thread Group looped 44 times
-- User parameter
-- Request
Beanshell Method
Alternately, you could do an array in javascript in connection with a counter. The Beanshell samplers have access to Jmeter variables and properties, allowing the beanshell sampler to read the counter value. This may be a faster, cleaner way then using User Parameters.
Beanshell structure
test plan
- Thread Group looped 44 times
-- Counter
-- Request
---- Beanshell pre-processor
Beanshell Pseudo code would be
def counter = value of Jmeter Counter
def array = array of values
declare the variable "sampler_value" to be used by sampler
def sampler_value = array # counter
Counter with CharAt function
If you only need to generate characters, you could use the javascript function to utilize the function charAt, using the value from the Counter. Basic structure would be:
test plan
- Thread Group looped 44 times
-- Counter
-- Request
with the request using something like ${__javaScript(charAt(${counter})) as the parameter value. You may have to use JEXL instead of javaScript or evalVar/V/eval inside the charAt function.
Question: I am wondering which is the optimal solution for dealing with Arrays in Excel 2003 VBA
Background: I have a Macro in Excel 2003 that is over 5000 lines. I have built it over the last 2 years adding new features as new Procedures, which helps to segment the code and debug, change, or add to that feature. The downside is that I am using much of the same base information in multiple procedures, which requires me to load it into arrays with minor differences multiple times. I am now running into issues with the length of run time, so I am now able to do a full rewrite.
This file is used to grab multiple items of manufacturing flows (up to 4 different set ups with a total of up to 10 distinct flows , of up to 1000 steps each) with the information being Flow specific, Sub-Flow specific for grouping / sorting purposes, and Data (such as movements, inventory, CT, ...)
It then will stick the data onto multiple sheets used to manage the process utilizing data sheets to be perused, charts, and Cell Formatting to denote process flow capability / history.
The Flow is in the Excel File, while the Manufacturing data is read in with 7 different OO4O Oracle SQL pulls, some reused multiple times
The Arrays are:
arrrFlow(1 to 1000, 1 to 4) as a Record Type with 4 strings
arrrSubFlow(1 to 1000, 1 to 10) as a Record Type with 4 strings, 2 integers, and 1 single
arrrData(1 to 1000, 1 to 10) as a Record Type with 1 string, 4 integers, 12 longs, and 1 single
arriSort(1 to 1000, 1 to 4) as Integer (Used as a pointer Array to sort the Flow, Sub Flow, and Data in a Group, Sub Group, and Step order while leaving the original arrays in Step order)
Possibilities:
1) Rewrite the macro into one big procedure that loads the data into master arrays dimensioned within the Procedure once
Pro: Dimensioned in the Procedure rather than as a Public Variable in the Module and not passed.
Con: Harder to debug with one mega procedure instead of multiple smaller ones.
2) Keep macro with multiple procedures but passing the Arrays
Pro: Easier to debug code with multiple smaller procedures.
Con: Passing Arrays (Expensive?)
3) Keep macro with multiple procedures but with the Arrays being Public Dim'ed variables in the Module
Pro: Easier to debug code with multiple smaller procedures.
Con: Public Arrays (Expensive?)
So, what's the community's verdict? Does anyone know the expense of using Public Arrays vs Passing Arrays? Is the Cost of either of these worth losing the ease of having my procedures being focused on one feature?
UPDATE:
I load Inventory Data at a discrete level (multiple per Step), Moves Data at a aggregate level (one per step), and the Beginning of Shift Inventory at an aggregate level. I aggregate the Inventory data by step placing it in Work State categories (Run, Wait,...) I create targets off data already on the sheets.
I have a Flow sheet that shows the Work Flows by Type, currently 3 products have a similar but not exactly the same flow, and 2 products are a different flow, that are similar but again not the same as each other. I have assigned each set of steps in the different flows a group and sub-group.
I place this data on multiple sheets, some in Step Order, some in group / sub-group order. I also need the data summed up by group and product, group / sub-group and product, portion of the line and product, and product.
I use Record Types so I actually have a readable three dimensional array, arrSubFlow(1,1).strStep (Step Name of the 1st Step of the 1st Device), arrData(10,5).lngYest (Yesterday's movement for the 10th Step of the 5th Device).
My main point of optimization is going to be in the section where I create 10 pages from scratch every single time. With Merging Cells, Borders, Headers, ... This is a very time consuming process. I will add a section that will compare my data with the page to see if it needs to be changed and if so, only then recreate it otherwise, I'll clear each section of data and only write data that changes to the sheet. This will be huge, based on my time logging data. However, whenever I update code, I always try to improve other aspects of the code as well. I see the loading of the data into a Structure (Array, RecordSet, Collection) once as both a little bit of optimization, but more so for data integrity, so I do not have the opportunity to load it differently for different sheets.
The main issues I see getting away from Arrays right now are:
* Already heavily invested in them, but this is not a good enough reason to not change
* Don't know if there is much cost to passing them, since it will by ByRef
* I use a Sort Function to create a Sorted "Pointer" array that lets me leave the Array in Step Flow order, while easily referencing it by Group / Sub-group order.
Since I am always trying to make my code for now and the future, I am not against updating the arrays to either RecordSets or Collections, but not merely for the sake of changing them to learn something cool. My arrays work and from my research, they add seconds to the run time, not substantial amounts for this 2 minute report. So If another structure is easier to update in the future than Two-dimensional Arrays of Record Types, then please let me know, but does anyone know the cost of passing an Array to a procedure, assuming you are not doing a ByVal pass?
You've provided a good bit of detail, but it's still quite difficult to understand exactly what's going on without seeing some code. In your question, I can identify at least 4 big topics that you interweave throughout: Manufacturing, Data Access, VBA, and Coding Best-Practices. It's hard for me to tell exactly what you're asking because your question scope is huge. Either way, I appreciate your trying to write better code in VBA.
It's hard for me to understand exactly what you plan to do with the arrays. You say:
The downside is that I am using much of the same base information in multiple procedures, which requires me to load it into arrays with minor differences multiple times.
I'm not sure what you mean here. Are you using arrays to represent a row of data that you retrieved from a database? If so, you might consider using class modules instead of the usual "macro" modules. These will allow you to work with full-blown objects instead of arrays of values (or references, as the case may be). Classes take more work to set up and consume, but they make your code a lot easier to work with and will greatly help you to segment your code.
As user Emtucifor already pointed out, there may be objects such as ADO Recordset objects (which may require Access to be installed...not sure) that can help greatly. Or you might create your own.
Here's a long example of how using a class might help you. Although this example is lengthy, it will show you how a few principles of object-oriented programming can really help you clean up your code.
In the VBA editor, go to Insert > Class Module. In the Properties window (bottom left of the screen by default), change the name of the module to WorkLogItem. Add the following code to the class:
Option Explicit
Private pTaskID As Long
Private pPersonName As String
Private pHoursWorked As Double
Public Property Get TaskID() As Long
TaskID = pTaskID
End Property
Public Property Let TaskID(lTaskID As Long)
pTaskID = lTaskID
End Property
Public Property Get PersonName() As String
PersonName = pPersonName
End Property
Public Property Let PersonName(lPersonName As String)
pPersonName = lPersonName
End Property
Public Property Get HoursWorked() As Double
HoursWorked = pHoursWorked
End Property
Public Property Let HoursWorked(lHoursWorked As Double)
pHoursWorked = lHoursWorked
End Property
The above code will give us a strongly-typed object that's specific to the data with which we're working. When you use multi-dimension arrays to store your data, your code resembles this: arr(1,1) is the ID, arr(1,2) is the PersonName, and arr(1,3) is the HoursWorked. Using that syntax, it's hard to know what is what. Let's assume you still load your objects into an array, but instead use the WorkLogItem that we created above. This name, you would be able to do arr(1).PersonName to get the person's name. That makes your code much easier to read.
Let's keep moving with this example. Instead of storing the objects in array, we'll try using a collection.
Next, add a new class module and call it ProcessWorkLog. Put the following code in there:
Option Explicit
Private pWorkLogItems As Collection
Public Property Get WorkLogItems() As Collection
Set WorkLogItems = pWorkLogItems
End Property
Public Property Set WorkLogItems(lWorkLogItem As Collection)
Set pWorkLogItems = lWorkLogItem
End Property
Function GetHoursWorked(strPersonName As String) As Double
On Error GoTo Handle_Errors
Dim wli As WorkLogItem
Dim doubleTotal As Double
doubleTotal = 0
For Each wli In WorkLogItems
If strPersonName = wli.PersonName Then
doubleTotal = doubleTotal + wli.HoursWorked
End If
Next wli
Exit_Here:
GetHoursWorked = doubleTotal
Exit Function
Handle_Errors:
'You will probably want to catch the error that will '
'occur if WorkLogItems has not been set '
Resume Exit_Here
End Function
The above class is going to be used to "do something" with a colleciton of WorkLogItem. Initially, we just set it up to count the total number of hours worked. Let's test the code we wrote. Create a new Module (not a class module this time; just a "regular" module). Paste the following code in the module:
Option Explicit
Function PopulateArray() As Collection
Dim clnWlis As Collection
Dim wli As WorkLogItem
'Put some data in the collection'
Set clnWlis = New Collection
Set wli = New WorkLogItem
wli.TaskID = 1
wli.PersonName = "Fred"
wli.HoursWorked = 4.5
clnWlis.Add wli
Set wli = New WorkLogItem
wli.TaskID = 2
wli.PersonName = "Sally"
wli.HoursWorked = 3
clnWlis.Add wli
Set wli = New WorkLogItem
wli.TaskID = 3
wli.PersonName = "Fred"
wli.HoursWorked = 2.5
clnWlis.Add wli
Set PopulateArray = clnWlis
End Function
Sub TestGetHoursWorked()
Dim pwl As ProcessWorkLog
Dim arrWli() As WorkLogItem
Set pwl = New ProcessWorkLog
Set pwl.WorkLogItems = PopulateArray()
Debug.Print pwl.GetHoursWorked("Fred")
End Sub
In the above code, PopulateArray() simply creates a collection of WorkLogItem. In your real code, you might create class to parse your Excel sheets or your data objects to fill a collection or an array.
The TestGetHoursWorked() code simply demonstrates how the classes were used. You notice that ProcessWorkLog is instantiated as an object. After it is instantiated, a collection of WorkLogItem becomes part of the pwl object. You notice this in the line Set pwl.WorkLogItems = PopulateArray(). Next, we simply call the function we wrote which acts upon the collection WorkLogItems.
Why is this helpful?
Let's suppose your data changes and you want to add a new method. Suppose your WorkLogItem now includes a field for HoursOnBreak and you want to add a new method to calculate that.
All you need to do is add a property to WorkLogItem like so:
Private pHoursOnBreak As Double
Public Property Get HoursOnBreak() As Double
HoursOnBreak = pHoursOnBreak
End Property
Public Property Let HoursOnBreak(lHoursOnBreak As Double)
pHoursOnBreak = lHoursOnBreak
End Property
Of course, you'll need to change your method for populating your collection (the sample method I used was PopulateArray(), but you probably should have a separate class just for this). Then you just add your new method to your ProcessWorkLog class:
Function GetHoursOnBreak(strPersonName As String) As Double
'Code to get hours on break
End Function
Now, if we wanted to update our TestGetHoursWorked() method to return result of GetHoursOnBreak, all we would have to do as add the following line:
Debug.Print pwl.GetHoursOnBreak("Fred")
If you passed in an array of values that represented your data, you would have to find every place in your code where you used the arrays and then update it accordingly. If you use classes (and their instantiated objects) instead, you can much more easily update your code to work with changes. Also, when you allow the class to be consumed in multiple ways (perhaps one function needs only 4 of the objects properties while another function will need 6), they can still reference the same object. This keeps you from having multiple arrays for different types of functions.
For further reading, I would highly recommend getting a copy of VBA Developer's Handbook, 2nd edition. The book is full of great examples and best practices and tons of sample code. If you're investing a lot of time into VBA for a serious project, it's well worth your time to look into this book.
It sounds like maybe Excel and arrays are not the best tools for the job you're doing. If you could please explain a little bit about the type of data that you're working with and what you're doing, that will really help provide a better answer. Give as much detail as you can about the types of manipulations you're doing on the data and what the inputs and outputs are.
I'm going to give some highlights that I think will help you, and then may edit my answer to be more complete as I get responses from you, and so I have more time to flesh things out a bit.
There is an object that naturally handles the record-type objects you're working with called a Recordset. In the VBA editor, go to Tools -> References and add Microsoft ActiveX Data Objects 2.X Library (the highest one on your machine). You can declare an object of type ADODB.Recordset, then do Recordset.Fields.Append to add fields to it, then .Open it and finally .AddNew, set field values, and .Update. This is a natural object to pass around in programs as an input or output parameter. It has natural traversal and positioning functions (.Eof, .Bof, .AbsolutePosition, .MoveNext, .MoveFirst, .MovePrevious) and supports searching and filtering (.Filter = "Field = 'abc'", .Find and so on).
I don't recommend using public variables, though without an understanding of what you're doing I can't really advise you well here.
I also would avoid one big procedure. Code should be broken out into reusable functional units that do only one thing, whose names are essentially self-documenting about what they do.
If you want to improve the performance of your code, hit ctrl-break at random times while it's running and break into the code. Then press Ctrl-L to view the call stack. Make a note of what is in the list each time. If any item shows up a majority of the time, it is the bottleneck and is where you should spend your time trying to optimize it. However, I don't advise trying to optimize what you have until you make some higher-level decisions (like whether you will switch to a recordset).
I really need more information to help you better.
If you're interested, I'll work up some demonstration code that will show how useful the Recordset object is. Inserting the data from a Recordset into an Excel range is super easy with Recordset.GetRows or .GetString (though some array transposition may be required, that's not hard, either).
UPDATE: If your goal is to speed up your process, then before doing anything I think it's best to be armed with the knowledge of what is taking the most time. Would you please hit ctrl-break about 10 times and note down the call stack each time, then tell me what the most common items in the call stack are?
In terms of updating the speed of cell formatting, here's my experience:
Merge is the slowest operation you can possibly do. Try to avoid it if at all possible. Using "center across selection" is one alternative. Another is just not merging, but using some combination of sizing properly, borders, cell background color, and turning off gridlines for the entire workbook.
Apply borders or other formatting once to the largest thing possible instead of to many small things such as cell by cell. For example, if most cells have all borders but some don't, then apply all borders to the entire range and during your looping remove the ones you don't want. And even then, try to do entire rows and larger ranges.
Save a template file with borders and formatting already applied. Let's say you put one row in it with the formatting for a certain section. In one step duplicate that row into as many rows are needed for that section, say 20 rows, and they will all have the same formatting. Duplicating rows is MUCH faster than applying formatting cell by cell.
Also, I wouldn't automatically go for using classes. While OO is great and I do it myself (heck, I just built 8 classes for something the other day to model a hierarchical structure so I could easily expose the parts of it when I needed them), in practice it can be slower. A simple set of public variables in a class is faster than using getters and setters. A user defined Type is even faster than a class, but you can run into gotchas trying to pass around UDTs in classes (they have to be declared in a non-class public module and even then they can give problems).