I used FilterFunction_strConcat. Which Function do you mean? Where can
I find it?
Somehow I didn't understand what you want to tell me but I guessed the
following and it works:
instead of creating an expression[] array with a size depending of the
number of attributes the user wants shown in the map I defined a
recursive function in which a FilterFunction_strConcat gets an
expression[] with size=2 containing an attributeexpression (an
attribute) or a literalexpression (the seperator ";") and as
second element another FilterFunction_strConcat or (if it's the last
element) an attributeexpression.
The recursive function finally generates an expression which is used
to create the TextSymbolizer. And it works perfectly.
Which means that the FilterFunction_strConcat.setArgs(Expression[])
only works for arrays with two elements.
tony roth
Looks like there is a String concatenate function you could call
as well
in order to get what you want ... because of the annoying way the SLD
specification is written we need to have each function be unique
in name
and number of parameters.
So we have the "strConcat" function ... you will need to nest it
to get
what you want ....
Cheers.
Jody
> Hi list,
> I want to show a set of feature attributes (all Strings) as one
> label in the map next to the point/graphic. Like "1; London; 12"
> (number of item, name and a status). Since the user can toggle
check
> boxes to switch on/off single values I can not store all
information
> in one feature attribute. Instead of this I have n (currently 5)
> feature attributes for this. This is the way I thought it's the
> correct one:
>
> ---- code ----
> // after each attribute except the last one a seperator like ";"
> // textAttributes is a List of attributes the user wants to be shown
> // Attributes is a enum with all attributes
> Expression[] expressions = new
Expression[textAttributes.size()*2-1];
> int i = 0;
> for (Attributes a : Attributes.values()){
> if (textAttributes.contains(a)){
> // attribute expression for the attribute
> Expression attributeExpression =
>
FilterFactoryFinder.createFilterFactory().createAttributeExpression(a.name());
> // literal expression for the seperator
> LiteralExpression seperator =
>
FilterFactoryFinder.createFilterFactory().createLiteralExpression(";");
> expressions[i++]=attributeExpression;
> if (i> expressions[i++]=seperator;
> }
> }
> }
> // Filter to concatenate strings
> FilterFunction_strConcat concatFunction = new
> FilterFunction_strConcat();
> concatFunction.setArgs(expressions);
> // create TextSymbolizer (fill and font are handled above... not
> interesting here)
> myStyleBuilder.createTextSymbolizer(fill, new Font[]
> {gtFont},null, concatFunction, placement, null));
> ---- code ----
> My first problem was to find a possibility to concatenate strings.
> Since
>
http://udig.refractions.net/docs/api-geotools/org/geotools/filter/function/FilterFunction_strConcat.htmlhas
> a very poor javadoc explanation I just guessed that this
function is
> the correct one.
>
> What happend?
> Independet of the number of attributes I want to show (2,3,4,5)
only
> the first attribute combined with the first seperator (";") is
drawn.
> So I got "London;" instead of "London;1;3". If I flip the order of
> attributes I get "1;" instead of "1;London;3". As I said only the
> first two expressions (one attribute, one literal) are included.
Since
> these two are included I guess that the FilterFunction_strConcat is
> the correct way. Can someone help me with this?
> I debuged it and the expressions array is build correct, has no
null
> elements and all seems ok.
>
> Thank you,
> tony roth
>
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