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i have a vaadin application, and i used SQLContainer to display database records.
the issue that i want to make the SQLcontainer update itself when any database change occurs.
cam anyone help me please?
AFAIK you can't register a "listener" on changes in any database systems like MySQL, Oracle or MSSQL. Its not how databases are intended and architectured to work.
Workaround is to register JavaScript callback in Vaadin and update table every x seconds. This way you won't even need to enable PushMode - it will be still the client who will make requests to the server and not the other (dirty imo) way around.
Following example was tested on MySQL and Vaadin 7.3:
final VerticalLayout layout = new VerticalLayout();
setContent(layout);
final Table table = new Table("Table");
try
{
JDBCConnectionPool connectionPool = new SimpleJDBCConnectionPool("com.mysql.jdbc.Driver", "jdbc:mysql://localhost:3306/test", "root", "");
QueryDelegate qd = new FreeformQuery("select * from testTable", connectionPool, "id");
final SQLContainer c = new SQLContainer(qd);
table.setContainerDataSource(c);
}
catch (SQLException e)
{
e.printStackTrace();
}
layout.addComponent(table);
JavaScript.getCurrent().execute("setInterval(function(){refreshTable();},5000);");
JavaScript.getCurrent().addFunction("refreshTable", new JavaScriptFunction()
{
#Override
public void call(JSONArray arguments) throws JSONException
{
table.refreshRowCache();
}
});
Related
Somewhere in my Vaadin application, I'm getting this exception as soon as I connect using a second browser
Caused by: java.lang.RuntimeException: A connector with id 22 is already registered!
at com.vaadin.ui.ConnectorTracker.registerConnector(ConnectorTracker.java:133)
It happens always in the same place but I don't know why exactly as the reason for this must be somewhere else.
I think I might be stealing UI components from the other session - which is not my intention.
Currently, I don't see any static instances of UI components I might be using in multiple sessions.
How can I debug this? It's become quite a large project.
Any hints to look for?
Yes, this usually happens because you are attaching a component already attached in other session.
Try logging the failed connector with a temporal ConnectorTracker, So the next time that it happens, you can catch it.
For example:
public class SomeUI extends UI {
private ConnectorTracker tracker;
#Override
public ConnectorTracker getConnectorTracker() {
if (this.tracker == null) {
this.tracker = new ConnectorTracker(this) {
#Override
public void registerConnector(ClientConnector connector) {
try {
super.registerConnector(connector);
} catch (RuntimeException e) {
getLogger().log(Level.SEVERE, "Failed connector: {0}", connector.getClass().getSimpleName());
throw e;
}
}
};
}
return tracker;
}
}
I think I might be stealing UI components from the other session - which is not my intention. Currently, I don't see any static instances of UI components I might be using in multiple sessions.
That was it. I was actually stealing UI components without prior knowledge.
It was very well hidden in a part which seems to be same for all instances. Which is true: the algorithm is the same.
Doesn't mean I should've reused the same UI components as well...
Thanks to those who took a closer look.
Here is how I fixed it -
1) look for components you have shared across sessions. For example if you have declared a component as static it will be created once and will be shared.
2) if you are not able to find it and want a work around until you figure out the real problem, put your all addComponent calls in try and in catch add following code -
getUI().getConnectorTracker().markAllConnectorsDirty();
getUI().getConnectorTracker().markAllClientSidesUnititialized();
getPage().reload():
This will clear old connectors and will reload the page properly only when it fails. For me it was failing when I was logged out and logged in back.
Once you find the real problem you can fix it till then inform your customers about the reload.
**** note - only solution is to remove shared components this is just a work around.
By running your application in debug mode (add ?debug at the end of URL in browser) you will be able to browse to the component, e.g:
-UIConnector(0)
--VerticalLayoutConnector(1)
---...
---LabelConnector(22)
where 22 is id from your stack trace. Find this component in your code and make sure that it is not static (yes, I saw such examples).
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In C# langauge exists global system variable for this purpose.
Environment.CommandLine
This property provides access to the program name and any arguments specified on the command line when the current process was started.
Dart is asynchronous langauge. It allows self starting processes.
void main() {
task("foo", callback1);
task("baz", callback2);
}
Package tasks.
void task(String name, action()) {
schedule();
addTask(name. action);
}
void schedule() {
// Here we start timer if it not started.
// This timer will get cmd line arguments
// And executes task specified in cmd line arguments
}
P.S.
An official answer from Dart Team: "Not planned".
I cannot understand: "Why this is possible in other platforms through their libraries but in Dart platform this is not possible?".
Why only through "main" parameters which even not ensures that other isolates not substitute these arguments on the surrogate parameters that are not a real OS process command line arguments)?
Here examples:
Go language
func main() {
fmt.Println(len(os.Args), os.Args)
}
Rust language
fn main() {
let args = os::args();
println!("The first argument is {}", args[1]);
}
C# language
class Sample {
public static void Main() {
Console.WriteLine();
String[] arguments = Environment.GetCommandLineArgs();
Console.WriteLine("GetCommandLineArgs: {0}", String.Join(", ", arguments));
}
}
Ruby language
ARGV.each do|a|
puts "Argument: #{a}"
end
Python language
import sys
print(sys.argv)
PHP language
foreach($argv as $value)
{
echo "$value\n";
}
Node.js language
process.argv.forEach(function (val, index, array) {
console.log(index + ': ' + val);
});
P.S.
Again, I am convinced that that Dart platform is not like everyone else.
This is only my opinion. It does not change anything.
Thanks, Günter Zöchbauer, for your concern, but do not need to edit this.
If you want to use command-line arguments outside main you have to pass it around. If you want, you can use a global for that.
This behavior is similar to Java, C and C++ (which you forgot to mention).
One big advantage of this approach is, that it is now easy to launch other programs by simply importing them (as a library) and invoking their main. It also makes argument handling more consistent with respect to isolates.
I'm relatively new to codename one. I'm trying to read text from a pure text url and store the text in a string. I tried using the java IO package but for some reason it doesn't seem to wirk with codename one. Please help.
David.
I think you might not really understand codenameone seeing as you tried to use the Java IO package. But anyway, this code might get you along
ConnectionRequest r = new ConnectionRequest();
r.setUrl("YOURURLHERE");
r.setPost(false);
r.addResponseListener(new ActionListener()
{
public void actionPerformed(ActionEvent ev)
{
try
{
NetworkEvent event = (NetworkEvent) ev;
byte[] data= (byte[]) event.getMetaData();
String decodedData = new String(data,"UTF-8");
System.out.println(decodedData);
} catch (Exception ex)
{
ex.printStackTrace();
}
}
});
NetworkManager.getInstance().addToQueue(r);
NOTE: Instead of using System.out.println, which works fine for debugging purposes, you probably want to add the text to your application with a GUI component. I'm not sure if this needs to be said, but it won't do any harm stating it again :)
I'm currently learning/testing BDD using SpecFlow, and it works great!
Before I choose to ask my question, I have read this one, and I felt like I had to ask my question despite the fact that the same problem is addressed, because of the Exception scenario which is not mentioned.
I'm actually testing this scenario:
Scenario: I should get an error whenever I try to remove an item from an empty stack
Given I have an empty stack
When I pop from it
Then I should get an error
public class StackBehaviour {
public void GivenIHaveAnEmptyStack() { stack = new CustomStack<string>(); }
// This will throw whenever called!
// So the Then method will never be run!
// I feel like I should just put a comment which says why it's empty,
// allowing a fellow programmer to understand the exact intention.
public void WhenIPopFromIt() { stack.Pop(); }
// It is here that it verifies whether the CustomStack meets the expected behaviour.
public void ThenIShouldGetAnError() {
Assert.Throws<IndexOutOfRangeException>(delegate {
stack.Pop();
});
}
private CustomStack<string> stack;
}
public class CustomStack<T> {
public T Pop() {
if (stack.Count == 0)
throw new IndexOutOfRangeException("Cannot pop from an empty stack!");
T item = stack[stack.Count-1];
stack.RemoveAt(stack.Count-1);
return item;
}
private ArrayList stack = new ArrayList();
}
I think that leaving a comment in the When method is correct, so that the business requirement doesn't lack any information, and on the code behind, I put it clear what my intention is exactly by commenting.
What do you think? Any other ideas why I shouldn't make it?
There is another trick that you can use where the bindings help make the feature's meaning a little clearer. In this case, let's start at the end.
Then I should get an error
Your problem is a basically here, you know want an error, but you don't know how to get it. In fact you've already missed it, the error has already occurred in the When step, and in your code example, you moved the action into the then step just so you could get the error.
But what if keep the when performing the action amd re-express our then to reflect what really happens
Then I should have had an error
Seems a trivial change but now our feature reflects that the error should have been associated with the When step and we are simply evaluating it later, and that is something we can code. We just need something to remember the error in the when and deliver it to the then.
private Exception errorFromWhen = null;
public void WhenIPopFromIt()
{
try
{
stack.Pop();
}
catch(Exception ex)
{
errorFromWhen = ex;
}
}
public void ThenIShouldGetAnError()
{
errorFromWhen.ShouldNotBeNull();
errorFromWhen.ShouldBe<IndexOutOfRangeException>();
}
SpecFlow has absolutely no problems with this, in fact due to its mini Dependency injection system, you can even pass this state between binding classes if necessary.
May a scenario not have a When in BDD?
In Specflow, neither given, when or then are mandatory.
However in your example, I don't believe this is a good use of Specflow and BDD. In this answer here Marcus states:
"BDD is about ensuring that we're building the right thing, TDD is about ensuring that we're building it right."
In your example the scope of what is being tested i.e. the CustomStack, should be tested via TDD. It is the end solution that makes use of the CustomStack should be tested via BDD (and hence SpecFlow) e.g. if this CustomStack was being exercised via a certain action on a website.
This answer is also pertinent to your question.
As far as I looked, there's no answered question about QTP's Ext. sdk on stackoverflow (and almost anywhere else on the net; there isn't even a appropriated tag for it...), so I'm aware it's unlikely I get my problem solved by asking , but whatever, it worth trying.
Anyway, before I lose the attention of anyone who never heard or used the Ext. sdk, maybe I will have more luck asking you to help me figure out how to locate the error log file QTP produces at run-time. I know such a file exists in the new UFT 11.5 version, but I couldn't locate it in QTP 10 or 11 (For the record, I don't talk about QTP's Log Tracking feature, but about the "meta" error log of errors/exceptions produced by QTP itself).
Now for the question:
I'm developing an extension for QTP to support native record and run tests on my application.
I'm currently able to import an object repository, and write test steps using The COM object testing agent I developed.
Problem started when I was trying to implement the IRecordable interface; I'm getting the IRecorder object from qtp, and even able to use it as ISuppressor object to exclude redundant steps from being recorded, but all my attempts to record a step (that is, to add new recorded objects to the repository, and add steps to the test) simply failed.
This is the code that I'm using:
public class MyTestingAgent :
AutInterface.ITestable,
AutInterface.IRecordable
{
QTPInterface.IRecorder recorder;
...
public void AutInterface.IRecordable.BeginRecording(object recorder)
{
IRecordSuppressor recordSuppressor = recorder as IRecordSuppressor;
recordSuppressor.Suppress(MyTestingAgentId,
"<Suppress><Item type=\"HWND\" value=\"[#HWND]\" /></Suppress>".Replace("[#HWND]", getMyAppHWND().ToString()));
this.recorder = recorder as QTPInterface.IRecorder;
...
}
public void recordNewObjStep(string parentName, string objName, string method, Object[] arguments)
{
object[] objectHyrarchy = new object[] { findObjectId(objName), findObjectId(parentName) };
string externalParent = null;
string appDescriptionXml = getDescriptionXml(parentName, objName);
try
{
recorder.Record(MyTestingAgentId, objectHyrarchy , appDescriptionXml, externalParent, method, arguments);
Trace.TraceInformation("Record successfully done.");
}
catch (Exception e)
{
Trace.TraceError("TEAAgent.recordSTElement: " + e.ToString());
}
}
...
}
I'm pretty sure all the arguments I send with the call to Record() are accurate. getDescriptionXml() and findObjectId() are used in different cases in the code, and works fine, the method name and argument are correct.
The annoying thing is that the call to Record doesn't even throw exception, and I get "Record successfully done." in the trace log. Needless to say no new object is created in the repository, and no step is added to the test.
As I can't debug QTP, I'm pretty much in the dark with what I'm doing wrong. That's why I'm asking for help with finding QTP's log file, or any other approach that might shed some light on the subject.
For QTP 11 you can turn on the logs by going to QTP's bin directory and running ClientLogs.exe.
Specifically for TEA extensibility do the following.
select the QTP node from the list on the left
find the LogCatPackTEA from the Available Categories list
Click the > button to move it to Selected Categories
Change TEAs level to Debug2 by selecting the category and changing the level
Click OK and run QTP
The logs will show up as QTP.log in the diretory specified in Path:
I'm curious on what the problem you're facing is, please update if you find the cause.