Casting string to a class type

is it possible to typecast a string to a classtype?
Example:
if a string is stored in a vector v and xyz is a class then is the following statement correct :
((xyz)v.elementAt[2]) ??
if not then what should i do to typecast it?

Navy_Coder wrote:
jverd wrote:
Navy_Coder wrote:
streetfi8er wrote:
is it possible to typecast a string to a classtype?
Example:
if a string is stored in a vector v and xyz is a class then is the following statement correct :
((xyz)v.elementAt[2]) ??
if not then what should i do to typecast it?Do you understand what typecasting is? What you're asking could be compared to taking your truck to a mechanic and asking if they can just turn it into a banana. You can't cast one object to another completely unrelated object.In fact, you can't cast objects at all.On second thought ......
enum Destination {
ETERNAL_DAMNATION, PITS_OF_HELL, OCEAN, VAT_OF_ACID;
ObjectManager.cast(myInstance, Destination.PITS_OF_HELLO);
ObjectManager.cast(calebsBrain, Destination.VAT_OF_ACID);
IMHO, this is still casting a reference, not an object.

Similar Messages

Is it possible to pass a string representing a class name in java as an arg

Hi, this is probably a bit of a stupid question, but one that has me quite confused all the same!
Is it possible to pass a string or class name etc. representing a type of class in java, to a method so that instead of having to redefine a method with say the following args:
public SolarPanels[] bestPVPanels(int budget, int percent) {
HashMap<Integer, SolarPanels> panelsMap = new HashMap<Integer, SolarPanels>();
}As at present needing to create a methods bestWindTurbine() and many others exactly the same, but for the type, I would instead like to be able to create a method like:
public Object[] bestRenewable(int budget, int percent, String aClassName) {
HashMap<Integer, aClassName > renewableMap = new HashMap<Integer, aClassName >();
}But cant sus how to do this as passing a String is off course going to cause problems unless its it possible to cast a string to a class name, any help or advance would be much appreciated.
Thanks in advance
Pat Nevin

pNev wrote:
But cant sus how to do this as passing a String is off course going to cause problems unless its it possible to cast a string to a class nameIt's not. You can do things like
Class.forName(classNameInString);But that will only return a Class object.
And as Java generics are erased at runtime, passing the class name to the method is useless as it is too late to use it anyways.
Ah, Peter's way is what I was thinking of. Too early in the morning.
Edited by: Kayaman on 23.6.2010 10:02

Coercing string to MovieClip class

I've been learning coercion between String and Number and
simple stuff, but now I have a class that the books don't cover.
This is best explained by example (this isn't the end goal, just a
learning example).
On the stage in frame 1, I have a MovieClip instance named
shape_mc.

In your first post you create a variable fubar with no
particular type and then make it a String by concatenating two
other variables. Next you attempt to cast String to MovieClip -
this is what is wrong with the code. Casting works only if an
object somehow is related to other object - in this instance if
fubar data type was related somehow to MovieClip (by extension for
example).
In order to use a string to point to an object - you need to
use an associative array syntax:
parentObject["string"] - given that an object "string" is in
the scope of parentObject.
The following syntax will work (if the movieclip is in the
scope of "this"):
var pre:String="shape";
var suf:String="_mc";
var fubar:* = MovieClip(this[pre + suf]);
Again, the key is to use a correct scope.
As for the flv files, there is no need to cast at all. FLVs
are not MovieClips. It is not clear how you want to play FLVs. Are
they on the server? If so - you need the url to them only (which
are strings). If they are progressive (downloaded via http) your
code may look something like:
var flvURL:String;
function clickListener(e:MouseEvent):void{
flvURL = e.target.name.toString().split("_")[0] + "_flv";
//some time later:
netStream.play(flvURL);
Of course this is just a concept - real code should be
different.

Determine class type of Generic Parameter (not via getGenericSuperclass()!)

I need to know the class type of a generic Parameter. Please imagine this class:
class MyGenericClass<T>
}In cases where other classes derived from MyClass and defined the generic parameter (like MyDerivedClass extends MyGenericClass<String>),
this snippets works just fine:
(Class<T>) ((ParameterizedType) getClass().getGenericSuperclass()).getActualTypeArguments()[0];But now I have no inheritance but the definition of the type parameter via instantiation:
MyGenericClass<String> entity = new MyGenericClass<String>();The method "getGenericSuperclass()" does not suit my needs because it does not target the actual class. Nor can "getTypeParameters() " help me...
After countless trying to retrieved the type information, I still have no clue how to determine for that case that (in my example) the type parameter
is a 'String'.
Does anyone know the solution?

Serethos_0 wrote:
Sure I could pass the class type itself as parameter to be stored in 'exportClassType'. But I only tried to adapt the idea used e.g. in Generic DAOs
as descibed here: [http://community.jboss.org/wiki/GenericDataAccessObjects]. The big difference is, that in the Generic DAO example the typed
information is available within the class definition ..
Besides that I am open for any other suggestion!I would recommend passing around the Class object as you say.
Some might suggest that you make MyGenericClass abstract, forcing any instantiation to be like this:
MyGenericClass<String> entity = new MyGenericClass<String>() {};That would indeed cause the String type parameter to be available at runtime, since you're creating an anonymous inner class. But it leads to a convoluted and extremely statically expensive instantiation pattern. Using the class object is a better solution IMO.

Error in converting character string to smalldatetime data type

I've installed SQL Server 2000 on my new laptop and Crystal Report XI, out of sudden, the Crystal Report to certain view can't run and I got the following error:
Details: 22007 [Microsoft][ODBC SQL Server Driver][SQL SERVER]Syntax Error cnverting character string to smalldatetime data type.
Any suggestions?
Hannah

Here is the view the err is complaining about:
SELECT     TOP 100 PERCENT Cur.Closed_Month, Cur.Closed_Year, Cur.Incidents_Closed, Prev.Incidents_Closed AS PrevIncidents_Closed,
                      YrAgo.Incidents_Closed AS YearIncidents_Closed
FROM         (SELECT     Closed_Month, Closed_Year, Incidents_Closed
                       FROM          dbo.Incidents_Closed) Cur INNER JOIN
                          (SELECT     Month(CONVERT(datetime, CAST(closed_month AS varchar) + '/01/' + CAST(closed_year AS varchar), 101) + 32) AS PrevMonth,
                                                   year(CONVERT(datetime, CAST(closed_month AS varchar) + '/01/' + CAST(closed_year AS varchar), 101) + 32) AS PrevYear,
                                                   Incidents_Closed
                            FROM          dbo.Incidents_Closed) Prev ON Cur.Closed_Month = Prev.PrevMonth AND Cur.Closed_Year = Prev.PrevYear INNER JOIN
                          (SELECT     Month(CONVERT(smalldatetime, CAST(closed_month AS varchar) + '/01/' + CAST(closed_year AS varchar), 101) + 366) AS PrevMonth,
                                                   year(CONVERT(smalldatetime, CAST(closed_month AS varchar) + '/01/' + CAST(closed_year AS varchar), 101) + 366) AS PrevYear,
                                                   Incidents_Closed
                            FROM          dbo.Incidents_Closed) YrAgo ON Cur.Closed_Month = YrAgo.PrevMonth AND Cur.Closed_Year = YrAgo.PrevYear
What confused me is that it works fine with my previous laptop. I wonder if there is any patch in Crystal Report or SQL server that used to support certain functions but not support them anymore....
Thanks
Hannah

1067: Implicit coercion of a value of type String to an unrelated type

Hi,
I created a webservice based on sql server 2005 with several methods successfully.
I am having headach now just trying to do some simple tests with Flex :-(
I used the "Import WebService", it created some code "generated webservices".
My test method p_SEARCH_NAME_SOUNDEX is based on a sql procedure wich take a varchar (128) as a parameter => NAL_NOM.
I am just trying to debug this function (error at line in red)
       public function searchEntry(name:String):void
            // Register the event listener for the findEntry operation.
            //agenda.addfindEntryEventListener(handleSearchResult);
            myWS.addp_SEARCH_NAME_SOUNDEXEventListener(handleSearchResult);
            // Call the operation if we have a valid name.
            if(name!= null && name.length > 0)
               myWS.p_SEARCH_NAME_SOUNDEX(name);
I got this error message:
067: Implicit coercion of a value of type String to an unrelated type generated.webservices:NAL_NOM_type1.
FLEX has creaetd a type called NAL_NOM_type1 for my class:
* NAL_NOM_type1.as
* This file was auto-generated from WSDL by the Apache Axis2 generator modified by Adobe
* Any change made to this file will be overwritten when the code is re-generated.
package generated.webservices
    import mx.utils.ObjectProxy;
    import flash.utils.ByteArray;
    import mx.rpc.soap.types.*;
     * Wrapper class for a operation required type
    public class NAL_NOM_type1
         * Constructor, initializes the type class
        public function NAL_NOM_type1() {}
        public var varchar:String;public function toString():String
            return varchar.toString();
I tried to do myWS.p_SEARCH_NAME_SOUNDEX(NAL_NOM_type1(name));
and also declared "name" as NAL_NOM_type1... but i still get this error.
This is how it declared my webservice method:
        public function p_SEARCH_NAME_SOUNDEX(nAL_NOM:NAL_NOM_type1):AsyncToken
             var _internal_token:AsyncToken = _baseService.p_SEARCH_NAME_SOUNDEX(nAL_NOM);
            _internal_token.addEventListener("result",_P_SEARCH_NAME_SOUNDEX_populate_results);
            _internal_token.addEventListener("fault",throwFault);
            return _internal_token;
I am even not on the level of assigning the data to my grid... i just want to see how it gets the data first in debug.
Thanks in advance for you help.
kr,
Meta

Thanks _Natasha_
I tried this:
var t = new NAL_NOM_type1();
t.varchar = name;
myWS.p_SEARCH_NAME_SOUNDEX(t);
It passes the 1st step :-) but I get another error now :-/
I think it try to get back NAL_NOM_type1 from the server of course on the WSDL side it know only NAL_NOM
Error: Cannot find definition for type 'http://NABSQL64DEV/::NAL_NOM_type1'
    at mx.rpc.xml::XMLEncoder/encodeType()[C:\autobuild\3.2.0\frameworks\projects\rpc\src\mx\rpc \xml\XMLEncoder.as:1426]
I guess I have to change my constructor type... i am not used to these stuff :-s
is this generating method the best way to access your data with webservices?
the turorials I saw are xml file or array based... is there any link similar to my issue so I can learn better?

Any Java built in function to get the Class type corresponding to primitive

I know it sounds strange but basically I have a Class and a String (I'm reading values from an XML file).
If the Class is a primitive type (boolean, byte, char, short, int, long, float, and double) I would have to convert the String into the corresponding types.
So I know how to do stuff like
Integer.parseInt("22");but for all the primitive types is there some method where I can simply get a way to do that without writing a whole bunch of if statements?

You could set up a class to parse your String. You could check to see if it contains a decimal point, if so then you check to see if it is less than float.MAX_VALUE etc same for the Integer family and you could use equals method to check if it is true or false.
one other way would be to use parseInt etc and catch exceptions if there is an error, this is a bad idea though and a dirty way to do things.
As suggested, maybe you have some idea of what data type your expecting and can limit the amount of parsing you have to do. Another way is to group all numeric values as doubles.
You could start with something like this adding other methods checking the max value of the data types.
public class StringParser
     public static void main(String[] args)
          String test = "1.0";
          System.out.println(containsDecimal(test));
          if (containsDecimal(test))
               decimalSizeFinder(test);
          else
               integerSizeFinder(test);
     static boolean containsDecimal(String input)
          for(int i=0; i<input.length(); i++)
               if (input.charAt(i) =='.')
                    return true;
          return false;
     static void integerSizeFinder(String input)
          long value = Long.parseLong(input);
          if(value <=Byte.MAX_VALUE)
               byte b = (byte)value;
          else if(value <= Short.MAX_VALUE)
               short s = (short)value;
          else if(value <=Integer.MAX_VALUE)
                int i = (int)value;
          //etc
        //Add code to assign the value to a variable someplace
     static void decimalSizeFinder(String input)
          double value = Double.parseDouble(input);
          if(value <=Float.MAX_VALUE)
               float f = (float)value;
       //Add code to assign the value to a variable someplace
}Message was edited by:
kikemelly
Message was edited by:
kikemelly

Seemingly unpredictable results when calling an overriden parent method on an instance of a child class casted to the parent class

I have a parent class with a sub-vi Override.vi, and a child which overrides this sub-vi. I create an instance of this child. I cast this child to it's parent class and store it in an array. Later, if I invoke the parent's 'Override.vi' on this child (casted to parent) then Labview 2013 seems to randomly choose whether to run the parent or the child override.vi. In Labview 2011 SP1 it would always call the childs version of override.vi (which while surprising to me was very useful). This has totally broken an application I have been developing, any insight as to how to control which override.vi is run would be helpful (re-casting to the child class isn't really an option, as there are in fact many child classes each with their own version of override.vi).

The actual data type of the wire is irrelevant in deciding which VI to run. The only thing that is relevant is the class of the object which is actually on the wire, so casting to the parent should not be relevant. *IF* the object really is a child, then LV should always call the child's VI, just like you say it works in 2011.
I suspect that what's happening in your case is that somewhere you're generating a parent and that's what's actually on the wire (e.g. maybe you have an error somewhere and a function outputs the default value, which is a parent). The fact that it didn't happen in 2011 doesn't mean it's a bug in 2013. It could be that something else has changed.
In any case, it's impossible to tell whether this is a misunderstanding, a bug in your code or a bug in LV without actual code. If you can post actual code which shows this, people can help. Otherwise (if it only happens in code you don't want to publish), you should try contacting NI directly so that you can at least show them the code.
Try to take over the world!

When I chage node Name in jtree. It's casted String object

Hello
My English ability is very poor sorry
now I make a tree
and
jtree.setEditable(true);
I change my tree node's value
from
-root
|-Hello
to
-root
|-Hi
after I chaged the value
the value's class type is String
I wan't to same class before change.
How can I do?
thank you

Hi! Take a look at treeCellEditors in Java Tutorial. You need to provide custom TreeCellEditor.
Denis Krukovsky
http://dotuseful.sourceforge.net/

Cast string to char

Hello;
Could anyone tell me how to cast a string to char?
for example;
String [] args = {"test", "hello","a"};
how can I cast the args[2] to char = 'a';
Thanks

Hello;
Could anyone tell me how to cast a string to char?
for example;
String [] args = {"test", "hello","a"};
how can I cast the args[2] to char = 'a';
Thanks
If you want to cast a String to a char you cannot. There are some conditions for casting. You just cannot cast anything primitive or object type to anything. how ever if you want to convert a String to a char array you could d othat as follows
refer to String API
public char[] toCharArray()
Converts this string to a new character array.

Cast to a user class

Hi.
Suposse that I have got a class "MyClass" and then i add an object of "MyClass" into a container. If i retrieve all the component of the container with the method container.getComponents() i cant cast the component that i am stored in the array into "MyClass". How can i do it?? Do you know a way to do it??
Thank you.

MyClass must extend Component to have any chance at working. Even if MyClass extends Component, I believe you can not cast an array of one type to an array of another, even if the elements of the array have a relationship that allows the cast. For example...
Component[] comps = new Component[2];
comps[0]=new TextField();
comps[1]=new TextField();
TextField[] obs = (TextField[]) comps;
Even though a TextField is a Component, and the elements of the array are TextFields, you get a class cast exception if you run the above code. The getComponents() method returns an array of Components so I believe you will have to cast each element.

RE: Set Table Column Class Type

Hi, there,
Right now I try to set column class type and in this way my table sort class can check integer column and sort like interger not string (1,3,20 not 1,20,3).
My problem is there is no setColumnClass method in AbstractTableModel.
How can I do it??
Thank you very much!!
Xin

There probably is a better solution.
But I overloaded the getColumnClass(int ColumnIndex) function in the Table Model and return different classes depending on the Column selected...
javax.swing.table.DefaultTableModel model =
new javax.swing.table.DefaultTableModel(){
public Class getColumnClass(int columnIndex)
if(columnIndex == 6) //or whatever column you Choose
return Integer.class;
if(columnIndex == 3)
return Integer.class;
else
return String.class;
TableSorter sorter = new TableSorter(model);
javax.swing.JTable table = new javax.swing.JTable(sorter);
I hope this helps...

Use cast('12345' as tab.col%type) as a substr - PLS-00220

Hello,
I like to make sure that my constructed string fits into my variable, in a flexible way.
The variable is like
declare t_comment tab.col%type; -- tab.col%type = varchar2(4)
and in the PLSQL I would like to do concat a string and make sure it fits in my variable, just cut the right end if it is too long. I want it to be dynamic, so NOT
t_comment := substr('1234567', 1, 4)
CAST () works like a substring operator if casting to a smaller data type, but also leads to hardcoding.
t_comment := cast ('1234567' as varchar2(4))
But I want
t_comment := cast ('1234567' as tab.col%type)
But that gives me a
PLS-00220: simple name required in this context.
And when I define a subtype
subtype comment_type is tab.col%type;
t_comment := cast ('1234567' as comment_type)
gives me a
PLS-00382: expression is of wrong type
The documentation is also clear:
CAST converts one built-in datatype or collection-typed value into another built-in datatype or collection-typed value.
But it would be so nice to prevent hardcoding, to the varchar2(4) datatype in this case.
Any suggestions on how to make this flexible?

Hello,
you can read the column length from the data dictionary and then use it in your SUBSTR instead of the hard coded value:
SELECT data_length
INTO v_length
FROM user_tab_cols
WHERE table_name = 'TAB'
AND column_name = 'COL';
t_comment := SUBSTR('1234567', 1, v_length);
Not as simple as a %TYPE, but just as flexible.
Regards
Marcus

Valid attribute-class types for af:regionDef ?

The only example or documentation I can find related to attributes of a regionDef are in /tagdoc/core/regionDef.html where there is an example which uses attributes of type String. Is it possible to use other classes? Any special syntax required in the EL expressions which use them? In another thread the following was suggested:
<af:commandButton text="Save"
action="#{sessionScope[regionAttrs.pageBeanName].save}"/>
where pageBeanName is an attribute of type String.
Unfortunately the page beans are mixed amoung the session and request scopes. Is there a way to pass in the scope or the actual pageBean? Alternatively I guess I could bind the action to a method with exception handling code so each scope could be checked in turn until the page bean was located but that seems a little heavy handed.

To answer my own question ;-)
Yes you can use other class types. Specifically I figured out how to use a Bean and more genericly a Java Interface (to which I passed the Bean). For example:
<faces-config>
<component-type>oracle.adfdemo.region.clientPageFooter</component-type>
    <component-class>
      oracle.adf.view.faces.component.UIXRegion
    </component-class>
    <component-extension>
      <region-jsp-ui-def>/regions/clientPageFooter.jspx</region-jsp-ui-def>
    </component-extension>
    <attribute>
      <attribute-name>pageBean</attribute-name>
      <attribute-class>demoOne.ClientPageFooter</attribute-class>
      <attribute-extension>
        <required>true</required>
      </attribute-extension>
    </attribute>
</component>
</faces-config>
package demoOne;
public interface ClientPageFooter
public String save();
public String reset();
public class ClientDetailPage implements ClientPageFooter
public String save()
    return "returnToClientList";
public String reset()
    return null;
<af:regionDef var="regionAttrs" >
              <af:commandButton text="Reset"
                                action="#{regionAttrs.pageBean.reset}"/>
              <af:commandButton text="Save"
                                action="#{regionAttrs.pageBean.save}"/>
              <af:commandButton text="Cancel" action="returnToClientList"/>
</af:regionDef>
          <af:region regionType="oracle.adfdemo.region.clientPageFooter"
                   id="clientPageFooter">
            <f:attribute name="pageBean" value="#{ClientDetailPage}"/>
          </af:region>Hope that helps someone :-)

Atg-rest-param-class-types

I am using something like this as input to an ATG rest webservice which does validation with an array input.
But i am not sure how to receive it in a formhandler especially from request.
{'atg-rest-param-class-types':{'container-class':
'java.util.ArrayList','element-class':
'java.lang.String'},'arg1':['sit','stay','speak']}
Pls help.
Should i use JSON input customizer?

Hi,
By receiving you mean you want to receive the output of this request which is in the form an array. In this case you can use atg-rest-output and type should be JSON. The output will parse itself into JSON. You'll not need Output Customizer for this.
Regards,
RahulV

Casting string to a class type

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