Given this hashmap:
HashMap<TitledPane, Boolean> paneMap = new HashMap<>();
I'm trying to set all values in the map to false (values are set selectively in the application after 'clearing' the map), but no matter what I have tried I cannot get an appropriate iterator which will allow me to set each boolean value. Can someone help please?
Just spoke to someone by phone and there is a very simple answer which I just didn't see in the end, because I tried to make it too complicated (I hadn't realised that 'put' replaces any existing values.
for (TitledPane p : paneMap.keySet()){
paneMap.put(p, Boolean.FALSE);
}
You can use lambda:
paneMap.replaceAll((k, v) -> Boolean.FALSE);
Related
like the title says, I want to add multiple values to my arrayList in Groovy.
But it is not accepted.
Collection<String> actorCollection = new ArrayList<>();
actorCollection.add("first","second");
If there is only a single value, it works perfectly.
Thanks in advance!
Use addAll: actorCollection.addAll("first","second")
Note: Groovy's list literal will give you an array list. So could just write def actorCollection = [] or even ... = ["first", "second"] to fill the list with the values right from the beginning.
I dont know how to describe the problem, so weird. I have function like this:
long getPersonId(...){
//...
}
The above function returns Id of a person based on some arguments.
So I logged the return value of the function and it is 1.
Then I have code like this:
person = myMap.get(getPersonId(..))
which returns null object but this returns a valid Person object, why?:
person = myMap.get(1)
But as I described before getPersonId(..) returns 1, which basically means
myMap.get(getPersonId(..)) == myMap.get(1)
myMap is typed as Map<Long, Person> myMap
What is happening here?
In Groovy, as in Java, 1 is an int literal, not a long, so
myMap.get(1)
is attempting to look up the key Integer.valueOf(1), whereas
myMap.get(getPersonId(..))
is looking up the key Long.valueOf(getPersonId(...)). You need to make sure that when you populate the map you are definitely using Long keys rather than Integer ones, e.g.
myMap.put(1L, somePerson)
In your original version of this question you were calling the GORM get method on a domain class rather than the java.util.Map.get method, and that should work as required as the GORM method call converts the ID to the appropriate type for you before passing it on to Hibernate.
I am so sorry the problem was when I initialize the map myMap
Map<Long, Person> myMap = [1, new Person()]
when you say something like this the key is an integerbut not a long still groovy not complaining.
So the problem is my method was returning a long value (1L) but my actual key on the map is integer value(1).
So changing my map init to Map<Long, Person> myMap = [1L, new Person()] solved the problem.
Probably this due to dynamic nature groovy but irritating unless you know how dynamic langs behave lol.
How Can I Make A Deep Copy of a Groovy ConfigObject? I see that I can make a shallow copy of the object with .clone(), but I want to make a full deep copy.
The problem with #HappyCoder86 answer is it assumes all config key / values are strings. If some of your config values are objects / closures (common in grails) below solution wont work.
Below solution may be slow but would work if you have values of type other then string
static def deepcopy(ConfigObject orig) {
ConfigObject copy = new ConfigObject()
orig.keySet().each { key ->
def value = orig.get(key)
if (value instanceof ConfigObject) {
value = deepcopy(value)
}
copy.put(key, value)
}
return copy
}
ConfigObject config = new ConfigSlurper().parse originalConf.toProperties()
ConfigObject clonedConfigObject = new ConfigSlurper().parse("${originalConfigObject.prettyPrint()}")
Won't work with entries having Class or Closure values types.
But will work with Lists and Maps.
I was wondering if CsvHelper by Josh Close has anything in the configuration I am missing to translate values to null. I am a huge fan of this library, but I always thought there should be some sort of configuration to let it know what values represent NULL in your file. An example would be a column with the value "NA", "EMPTY", "NULL", etc. I am sure I could create my own TypeConverter, but I was hoping there would be an easier option to set somewhere in a config as this tends to be fairly common with files I encounter.
Is there a configuration setting to do this relatively easily?
I found the TypeConversion in the CsvHelper.TypeConversion namespace but am not sure where to apply something like this or an example of the correct usage:
new NullableConverter(typeof(string)).ConvertFromString(new TypeConverterOptions(), "NA")
I am also using the latest version 2.2.2
Thank you!
I think some time in the last seven years and thirteen versions since this question was asked the options for doing this without a custom type map class expanded, e.g.:
csvReader.Context.TypeConverterOptionsCache.GetOptions<string>().NullValues.Add("NULL");
csvReader.Context.TypeConverterOptionsCache.GetOptions<DateTime?>().NullValues.AddRange(new[] { "NULL", "0" });
csvReader.Context.TypeConverterOptionsCache.GetOptions<int?>().NullValues.Add("NULL");
csvReader.Context.TypeConverterOptionsCache.GetOptions<bool>().BooleanFalseValues.Add("0");
csvReader.Context.TypeConverterOptionsCache.GetOptions<bool>().BooleanTrueValues.Add("1");
CsvHelper can absolutely handle nullable types. You do not need to roll your own TypeConverter if a blank column is considered null. For my examples I am assuming you are using user-defined fluent mappings.
The first thing you need to do is construct a CsvHelper.TypeConverter object for your Nullable types. Note that I'm going to use int since strings allow null values by default.
public class MyClassMap : CsvClassMap<MyClass>
{
public override CreateMap()
{
CsvHelper.TypeConversion.NullableConverter intNullableConverter = new CsvHelper.TypeConversion.NullableConverter(typeof(int?));
Map(m => m.number).Index(2).TypeConverter(intNullableConverter);
}
}
Next is setting the attribute on your CsvReader object to allow blank columns & auto-trim your fields. Personally like to do this by creating a CsvConfiguration object with all of my settings prior to constructing my CsvReader object.
CsvConfiguration csvConfig = new CsvConfiguration();
csvConfig.RegisterClassMap<MyClassMap>();
csvConfig.WillThrowOnMissingField = false;
csvConfig.TrimFields = true;
Then you can call myReader = new CsvReader(stream, csvConfig) to build the CsvReader object.
IF you need to have defined values for null such as "NA" == null then you will need to roll your own CsvHelper.TypeConversion class. I recommend that you extend the NullableConverter class to do this and override both the constructor and ConvertFromString method. Using blank values as null is really your best bet though.
I used "ConvertUsing"...
public class RecordMap : CsvHelper.Configuration.ClassMap<Record>
{
public RecordMap()
{
AutoMap();
Map(m => m.TransactionDate).ConvertUsing( NullDateTimeParser );
Map(m => m.DepositDate).ConvertUsing( NullDateTimeParser );
}
public DateTime? NullDateTimeParser(IReaderRow row)
{
//"CurrentIndex" is a bit of a misnomer here - it's the index of the LAST GetField call so we need to +1
//https://github.com/JoshClose/CsvHelper/issues/1168
var rawValue = row.GetField(row.Context.CurrentIndex+1);
if (rawValue == "NULL")
return null;
else
return DateTime.Parse(rawValue);
}
}
I have just started utilizing ArrayLists in some C# code and am having some problems when sorting.
First I define create an ArrayList object under my class:
ArrayList cutList = new ArrayList;
Then I set and sort the array list to find the minimum:
cutList.Add("2200","1800","1200","1");
int minList = (int)GetMinValue(cutList);
Using the function:
public static object GetMinValue(ArrayList arrList)
{
ArrayList sortArrayList = arrList;
sortArrayList.Sort();
return sortArrayList[0];
}
Later I try to find the index cutList[2] and I find "1200" because the function also sorted cutList. I have also had the same problem in the past, when I set a variable to an Application settings and then the Applications setting changes when I modify the variable. How to I correctly fix these problems. I have been learning C# on my own and am guilty of skipping around a little bit. Is there a lesson on Objects that I am missing?
The issue in your code is that ArrayList sortArrayList = arrList; does not copy arrList to sortArrayList: the assignment merely creates a new alias for the existing object. To make your code work, use
ArrayList sortArrayList = (ArrayList)arrList.Clone();
I must add that this is probably the most inefficient way of looking up the min element in a list, and also a rather archaic container. I would prefer using List<string> instead of ArrayList, and using LINQ's Min() function to get the minimum element.