I have unsuccessfully tried to append several times a method group() that returns a string. My code works well only for the times I call the method, but fails to append the number of times the user calls group().
For instances, the following code would append the resulting string from the group() call three times. Then, when I type "end", description() would print the three strings appended in sb. "start" is the token used to initiate each group() call (start is used in group()).
TOKEN :
{
< START: "start" >
| < END: "end" >
}
String description() :
{
StringBuffer sb = new StringBuffer();
}
{
{
sb.append(group());
sb.append(group());
sb.append(group());
}
< END >
{
return sb.toString();
}
}
However, what I am really trying to achieve is that, if the user calls group() four times (using the token "start"), the description method would append for groups of strings. Essentially, it would append the number of strings based on the user's input. I have been told a useful way to do it is using (group())*. Nevertheless, I haven't gotten it to work.
Try something like this:
String description() :
{
StringBuffer sb = new StringBuffer();
Object o;
}
{
(
o=group() {sb.append(o);}
)*
<END>
{
return sb.toString();
}
}
Related
Async method returns list with duplicated elements. It is async method which is using mysql connector to connect with database. Then it execute query (SELECT *) and by using MySqlDataReader - I save and add to list rows until last ReadAsync() call.
Asynchronous programming is still black magic for me - I would appreciate any feedback or indicating unlogical code lines with explanation.
This method will be used in my web api controller and method purpose is to return all entries from 'Posts' table. Code is working fine when I 'reset' temp object each loop by using
temp = new Post(); but I assume it is unacceptable ? What if my database would have not 15 but 15000 entries?
`
public async Task<List<Post>> GetPostsAsync()
{
List<Post> posts = new List<Post>();
Post temp = new Post();
try
{
await _context.conn.OpenAsync();
MySqlCommand cmd = new MySqlCommand("USE idunnodb; SELECT * FROM Posts;", _context.conn);
await using MySqlDataReader reader = await cmd.ExecuteReaderAsync();
while(await reader.ReadAsync())
{
temp.PostID = (int)reader[0];
temp.UserID = (int)reader[1];
temp.PostDate = reader[2].ToString();
temp.PostTitle = reader[3].ToString();
temp.PostDescription = reader[4].ToString();
temp.ImagePath = reader[5].ToString();
posts.Add(temp);
}
await _context.conn.CloseAsync();
}
catch (Exception ex)
{
return Enumerable.Empty<Post>().ToList();
}
return posts;
}
`
Looks like you can only read data by looping through MySqlDataReader, according to your code logic, you need to read each piece of data, and then add them to the List one by one for output.
Your code is behaving this way because temp has been declared & instantiated outside of your reader.ReadAsync() statement, you are updating the same object reference each time around the loop which is why you are seeing repeating objects in your list.
So you need to instantiate in reader.ReadAsync() loop:
while(await reader.ReadAsync())
{
Post temp = new Post();
...
}
I am trying to write a method that takes a username as its input and creates a SQL query statement which is then executed. As of right now, I am getting a NullPointer when I try to call result.getObject().
Here is my method for creating the SQL statement dynamically:
fun getByUsername(name: String): User?{
val sql = """SELECT * FROM usertable WHERE username="$name";"""
val result = DatabaseController().trySql(sql)
if (result != null) {
if (!result.isBeforeFirst) {
println("User was not found...")
return null
} else {
println("User found....")
return User(result.getObject("username").toString(),
result.getObject("password").toString(),
result.getObject("admin").toString().toBoolean())
}
}
return null
}
Method that executes query:
fun trySql(sqlCommand: String): ResultSet? {
var conn = this.connect()
println("trySql()-------Running query $sqlCommand")
var result = conn?.createStatement()?.executeQuery(sqlCommand)
conn?.close()
return result
}
The username I am running it on is in my table too, so that is not the issue. My method that creates a row in my table is working properly, so I know there is no issue with connecting to the database.
EDIT
If I just return result in trySql(), I no longer get any errors, but from my reading I am supposed to close connections after use?
Why you are having issues
You are closing the connection, which makes the ResultSet you get back no longer useful. You will have access to the result object, but the result object will be unable to read data from SQLite, leading to errors.
How to fix
You can pass some code to your trySql function, which will be performed with the connection still open, and then close after the passed block.
Example
Library
class Con(val con: Connection = DriverManager.getConnection(URL)): AutoCloseable by con {
fun <T> withSQL(query: String, block: (ResultSet)->T): T {
con.createStatement().use { statement ->
statement.executeQuery(query).use { results ->
return block(results)
}
}
}
}
Usage
Con().use { con ->
val result: Int = con.withSQL("SELECT * from example WHERE name='test'") {
it.getInt(1)
}
}
After reading this article:
http://blogs.msdn.com/b/tilovell/archive/2009/12/29/the-trouble-with-system-activities-foreach-and-parallelforeach.aspx
I have defined the ForEachFactory as follows:
public class ForEachFactory<T> : IActivityTemplateFactory
{
public Activity Create(DependencyObject target)
{
return new ForEach<T>
{
DisplayName = "ForEachFromFactory",
Body = new ActivityAction<T>
{
Argument = new DelegateInArgument<T>("item")
}
};
}
}
All works well but is it possible to check how that DelegeateInArgument in my case named "item" changes its value ?
So if i have defined an array in the variables section and initialized with
{1, 2, 3} i need a way to check how the "item" takes value 1, 2 and then 3.
To be more accurate, i've added this pic, with a breakpoint on the WriteLine activity inside the foreach. When the execution will stop there, is there a way to find out what the value of item is ?
EDIT 1:
Possible solution in my case:
After struggling a bit more i found one interesting thing:
Adding one of my custom activities in the Body of the ForEach, i am able to get the value of the item like this :
So, my activity derives from : CodeActivity
Inside the protected override String[] Execute(CodeActivityContext context) i am doing this job.To be honest, this solves the thing somehow, but it is doable only in my custom activities. If i would put a WriteLine there for example, i would not be able to retrieve that value.
you can access the DelegeateInArgument of a ForEach activity by inspecting the ModelItem trees parent and checking for DelegeateInArgument's. If you need a specific code example to achieve this I may need a some time to code the example. As it has been a long time since I did this, see my question i asked over on msdn
So basically where your break point is, you can access the variable values as these are defined with n the scope of your activity as 'variables'. However the 'item' variable is actually only accessible from the parent loop activity. So you have to get the model item of the current executing activity and then traverse up the tree to find the parent containing the desired DelegateInArgument.
Can you flesh out exactly what you want to achieve? Is it that when your debugging the workflow in the re-hosted designer you want to display the variable values to the user as they change in the UI?
Edit - added tracking example
So as your wanting to display the variable values during execution of the workflow we need to use tracking to achieve this. In the example your using the author has already implemented some basic tracking. So to achieve the extended variable tracking you want you will need to alter the tracking profile.
Firstly amend the WorkflowDesignerHost.xaml.cs file alter the RunWorkflow method to define the SimulatorTrackingParticipant as below.
SimulatorTrackingParticipant simTracker = new SimulatorTrackingParticipant()
{
TrackingProfile = new TrackingProfile()
{
Name = "CustomTrackingProfile",
Queries =
{
new CustomTrackingQuery()
{
Name = all,
ActivityName = all
},
new WorkflowInstanceQuery()
{
**States = {all },**
},
new ActivityStateQuery()
{
// Subscribe for track records from all activities for all states
ActivityName = all,
States = { all },
**Arguments = {all},**
// Extract workflow variables and arguments as a part of the activity tracking record
// VariableName = "*" allows for extraction of all variables in the scope
// of the activity
Variables =
{
{ all }
}
}
}
}
};
This will now correctly capture all workflow instance states rather than just Started/Completed. You will also capture all Arguments on each activity that records tracking data rather than just the variables. This is important because the 'variable' were interested in is actually (as discussed earlier) a DelegateInArgument.
So once we have changed the tracking profile we also need to change the SimulatorTrackingParticipant.cs to extract the additional data we are now tracking.
If you change the OnTrackingRecordReceived method to include the following sections these will capture variable data and also Argument data during execution.
protected void OnTrackingRecordReceived(TrackingRecord record, TimeSpan timeout)
{
System.Diagnostics.Debug.WriteLine(
String.Format("Tracking Record Received: {0} with timeout: {1} seconds.", record, timeout.TotalSeconds)
);
if (TrackingRecordReceived != null)
{
ActivityStateRecord activityStateRecord = record as ActivityStateRecord;
if (activityStateRecord != null)
{
IDictionary<string, object> variables = activityStateRecord.Variables;
StringBuilder vars = new StringBuilder();
if (variables.Count > 0)
{
vars.AppendLine("\n\tVariables:");
foreach (KeyValuePair<string, object> variable in variables)
{
vars.AppendLine(String.Format(
"\t\tName: {0} Value: {1}", variable.Key, variable.Value));
}
}
}
if (activityStateRecord != null)
{
IDictionary<string, object> arguments = activityStateRecord.Arguments;
StringBuilder args = new StringBuilder();
if (arguments.Count > 0)
{
args.AppendLine("\n\tArgument:");
foreach (KeyValuePair<string, object> argument in arguments)
{
args.AppendLine(String.Format(
"\t\tName: {0} Value: {1}", argument.Key, argument.Value));
}
}
//bubble up the args to the UI for the user to see!
}
if((activityStateRecord != null) && (!activityStateRecord.Activity.TypeName.Contains("System.Activities.Expressions")))
{
if (ActivityIdToWorkflowElementMap.ContainsKey(activityStateRecord.Activity.Id))
{
TrackingRecordReceived(this, new TrackingEventArgs(
record,
timeout,
ActivityIdToWorkflowElementMap[activityStateRecord.Activity.Id]
)
);
}
}
else
{
TrackingRecordReceived(this, new TrackingEventArgs(record, timeout,null));
}
}
}
Hope this helps!
We have a word document with [Signature] Key as a paragraph, All we need to do is replace with signature with some Names, based on the names we need to repeat the [signature] key.
Ex: if names are containing 10 to 15 characters it should be repeat 2 times in a row like below
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
if names are containing 5 charecters should be repeat 3 times
XXXXXXXXXXXXXX XXXXXXXXXXXXXX XXXXXXXXXXXXXXX
based on the name node will repeat...?
please help how to solve this task ......
To find and replace text in a word document, Aspose.Words provides IReplacingCallback interface which can easily be used to achieve your goal. I used a static string to test the scenario as I don't have the details of your data source. You will require to add a check in your code based on the name length, you need to add the signature. Check the following sample:
//Open the file
Document doc = new Document("c:\\data\\Signature.docx");
//Specify the string / tag to be replace
doc.Range.Replace(new Regex(#"\[Signature\]", RegexOptions.IgnoreCase), new ReplaceEvaluatorSignature(), false);
//Save the updated document
doc.Save("c:\\data\\Output.docx");
/// <summary>
/// Class to change the signature
/// </summary>
public class ReplaceEvaluatorSignature : IReplacingCallback
{
/// <summary>
/// This method is called by the Aspose.Words find and replace engine for each match.
/// This method highlights the match string, even if it spans multiple runs.
/// </summary>
ReplaceAction IReplacingCallback.Replacing(ReplacingArgs e)
{
// This is a Run node that contains either the beginning or the complete match.
Node currentNode = e.MatchNode;
// The first (and may be the only) run can contain text before the match,
// in this case it is necessary to split the run.
if (e.MatchOffset > 0)
currentNode = SplitRun((Run)currentNode, e.MatchOffset);
// This array is used to store all nodes of the match for further removing.
ArrayList runs = new ArrayList();
// Find all runs that contain parts of the match string.
int remainingLength = e.Match.Value.Length;
while (
(remainingLength > 0) &&
(currentNode != null) &&
(currentNode.GetText().Length <= remainingLength))
{
runs.Add(currentNode);
remainingLength = remainingLength - currentNode.GetText().Length;
// Select the next Run node.
// Have to loop because there could be other nodes such as BookmarkStart etc.
do
{
currentNode = currentNode.NextSibling;
}
while ((currentNode != null) && (currentNode.NodeType != NodeType.Run));
}
// Split the last run that contains the match if there is any text left.
if ((currentNode != null) && (remainingLength > 0))
{
SplitRun((Run)currentNode, remainingLength);
runs.Add(currentNode);
}
//Name is defined for testing, replace it with your data source
// string TestName = "Nausherwan Aslam";
//Following is to test less or equal to 10 charators
string TestName = "Nausherwan";
// Create Document Buidler
DocumentBuilder builder = new DocumentBuilder(e.MatchNode.Document as Document);
builder.MoveTo((Run)runs[runs.Count - 1]);
if (TestName.Length > 10)
{
builder.Write(TestName+ " " + TestName);
}
else
{
builder.Write(TestName + " " + TestName + " " + TestName);
}
// Now remove all runs in the sequence.
foreach (Run run in runs)
run.Remove();
// Signal to the replace engine to do nothing because we have already done all what we wanted.
return ReplaceAction.Skip;
}
private static Run SplitRun(Run run, int position)
{
Run afterRun = (Run)run.Clone(true);
afterRun.Text = run.Text.Substring(position);
run.Text = run.Text.Substring(0, position);
run.ParentNode.InsertAfter(afterRun, run);
return afterRun;
}
}
Im trying to extend the flex ArrayCollection to be able to search for an object containing specific data and give it back.
Here is my function:
public function getItemContaining(value: String): Object {
//Loop through the collection
for each(var i: Object in this) {
//Loop through fields
for(var j: String in i) {
//If field value is equal to input value
if(i[j] == value) {
return i;
}
}
}
//If not found
return null;
}
Problem is j is always null so the second loop never works. So I read flex loop descriptions and actually it should work just fine. What can possibly be the problem?
Try it like this:
for (var name:String in myObject){
trace(name + ":" + myObject[name];
}
Okay that was actually the same you were doing. The error must be in this line:
for each(var i: Object in this) {
Try using this:
for each(var i: Object in this.source) {
My first instinct would be to have a look at data type. You're setting up a loop declaring j:String and the symptom is that j is always null. This suggests to me that Flex is failing to interpret the elements of i as strings. If Flex only recognizes the elements of i as Objects (because all Strings are Objects, and Objects are the lowest common denominator), it would return null for j:String.
Try this for your inner loop:
for(var j: Object in i) {
//If field value is equal to input value
if(i[j] is String && (i[j] as String) == value) {
return i;
}
}
if you are using ArrayCollection as your datasource, you should look at using the IViewCursor interface. You can supply a custom compare function, or supply the fields top compare to. This interface is well documented with examples in adobe/livedocs
var _cursor:IViewCursor;
var _idSortField:SortField;
var _idSort:Sort = new Sort();
_idSortField = new SortField();
_idSortField.compareFunction = this.myCompareFunction;
_idSort.fields = [_idSortField];
myArrayCollection.sort = _idSort;
myArrayCollection.refresh();
_cursor = myArrayCollection.createCursor();
if (_cursor.findAny(search))
return _cursor;
if you are search for a value in a specific property, then its even easier. Here's the link to adobe livedocs on this topic