FindNextItem (GenericNamedArraylist function): Difference between revisions

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==Examples==
==Examples==
===Successful selection===
 
The following request contains two <var>FindNextItem</var> calls and one <var>[[FindPreviousItem_(GenericNamedArraylist_function)|FindPreviousItem]]</var> call, each with a class Variable as the function in the SelectionCriterion:
====Successful selection====
The following request contains two <var>FindNextItem</var> calls and one <var>[[FindPreviousItem_(GenericNamedArraylist_function)|FindPreviousItem]]</var> call, each with a class Variable as the function in the <var>SelectionCriterion</var>:
<p class="code">begin
<p class="code">begin
   class staff
   class staff
Line 65: Line 66:
   print %stf:myprint
   print %stf:myprint
   
   
   %stf = %old:findPreviousItem(AND(Lt(name, 'Starks'), -
   %stf = %old:findPreviousItem(AND(Lt(name, 'Starks'), Eq(status, 'employed')))
                              Eq(status, 'employed')))
   print %stf:myprint
   print %stf:myprint
end
end
Line 76: Line 76:
Red employed
Red employed
</p>
</p>
===Failed selection, UnicodeNamedArraylist===
 
====Failed selection, UnicodeNamedArraylist====
The following fragment also contains one <var>FindNextItem</var> call and one <var>FindPreviousItem</var> call.
The following fragment also contains one <var>FindNextItem</var> call and one <var>FindPreviousItem</var> call.
The <var>FindPreviousItem</var> call finds no matching item:
The <var>FindPreviousItem</var> call finds no matching item:
<p class="code">   %k  is unicodeNamedArraylist of longstring
<p class="code">%k  is unicodeNamedArraylist of longstring
    %k = new
%k = new
    %k('&sect;Jan':u) = 'Orion'
%k('&sect;Jan':u) = 'Orion'
    %k('&sect;Apr':u) = 'Leo'
%k('&sect;Apr':u) = 'Leo'
    %k('&sect;Mar':u) = 'Cancer'
%k('&sect;Mar':u) = 'Cancer'
    %k('&sect;Jun':u) = 'Ursa Minor'
%k('&sect;Jun':u) = 'Ursa Minor'
    %k('&sect;Nov':u) = 'Andromeda'
%k('&sect;Nov':u) = 'Andromeda'
    %k('&sect;Dec':u) = 'Aries'
%k('&sect;Dec':u) = 'Aries'
    %k('&sect;Feb':u) = 'Canis Major'
%k('&sect;Feb':u) = 'Canis Major'


    %sel is object selectionCriterion for longstring
%sel is object selectionCriterion for longstring
    %sel2 is object selectionCriterion for longstring
%sel2 is object selectionCriterion for longstring
    %sel = OR(LT(this, 'C'), EQ(this, 'Taurus'))
%sel = OR(LT(this, 'C'), EQ(this, 'Taurus'))
    %sel2 = EQ(this, 'Taurus')
%sel2 = EQ(this, 'Taurus')


    print %k:findNextitem(%sel)
print %k:findNextitem(%sel)
    print %k:findPreviousitem(%sel2)
print %k:findPreviousitem(%sel2)
</p>
</p>



Latest revision as of 19:42, 1 November 2012

Next item that matches some selection criteria (FloatNamedArraylist, NamedArraylist, and UnicodeNamedArraylist classes)


FindNextItem searches "forward" in the FloatNamedArraylist, NamedArraylist, or UnicodeNamedArraylist to find and return the next item that matches a specified criterion. The criterion is supplied by the SelectionCriterion object that is a required FindNextItem parameter. If no item satisfies the criterion, the request is cancelled and an ItemNotFound exception is thrown.

Syntax

%item = anyNal:FindNextItem( selectionCriterion, [Start= number]) Throws ItemNotFound

Syntax terms

%item A variable of the type of the item in the FloatNamedArraylist, NamedArraylist, or UnicodeNamedArraylist to contain the item that is located by the search.
anyNal A FloatNamedArraylist, NamedArraylist, or UnicodeNamedArraylist object.
selectionCriterion A SelectionCriterion object, which is a relational expression that is applied to a anyNal item values to determine whether the value satisfies the expression. The expression consists of a function, an operator, and a numeric or string value.

For example, GT(this, -11) is the criterion this > -11, where this is an identity function that simply returns the item's value. The first item tested by FindNextItem that satisfies this expression is the method's return value.

The function in the criterion is a method value (a method or class member name literal, or a method variable) for a method that operates on items of the type specified on the anyNal declaration and that returns a numeric or string value. This is described further in "Specifying a SelectionCriterion's parameters".

Start The number of the item after which to begin the search. If the number value of Start is 2, item 3 is the first item considered. The value of Start may be 0 through the number of items in the FloatNamedArraylist, NamedArraylist, or UnicodeNamedArraylist. For an array list of three items, number may be 0, 1, 2, or 3.

This is an optional, name required, argument which defaults to 0. If you specify a value, the parameter name number is required.

Usage notes

  • If the value of Start is greater than the number of items in the FloatNamedArraylist, NamedArraylist, or UnicodeNamedArraylist, the request is cancelled. If the value of Start is equal to the number of items, the request is cancelled, but an ItemNotFound exception is thrown.
  • FindNextItem is available in Sirius Mods Version 7.6 and later.

Examples

Successful selection

The following request contains two FindNextItem calls and one FindPreviousItem call, each with a class Variable as the function in the SelectionCriterion:

begin class staff public variable name is string len 20 variable status is string len 8 constructor newf(%a is string len 10, - %b string len 8) function myprint is longstring end public constructor newf(%a is string len 10, - %b string len 8) %this:name = %a %this:status = %b end constructor function myprint is longstring return %this:name with ' ' with %this:status end function end class %stf is object staff %old is namedArraylist of object staff %old = new %old('Jim') = newf('Red', 'employed') %old('Jed') = newf('Black', 'retired') %old('Jan') = newf('Green', 'employed') %old('Jud') = newf('Brown', 'retired') %old('Jon') = newf('White', 'tired') %stf = %old:findNextItem(Eq(status, 'employed')) print %stf:myprint %stf = %old:findNextItem(Gt(name, 'Starks')) print %stf:myprint %stf = %old:findPreviousItem(AND(Lt(name, 'Starks'), Eq(status, 'employed'))) print %stf:myprint end

The result is:

Green employed White tired Red employed

Failed selection, UnicodeNamedArraylist

The following fragment also contains one FindNextItem call and one FindPreviousItem call. The FindPreviousItem call finds no matching item:

%k is unicodeNamedArraylist of longstring %k = new %k('§Jan':u) = 'Orion' %k('§Apr':u) = 'Leo' %k('§Mar':u) = 'Cancer' %k('§Jun':u) = 'Ursa Minor' %k('§Nov':u) = 'Andromeda' %k('§Dec':u) = 'Aries' %k('§Feb':u) = 'Canis Major' %sel is object selectionCriterion for longstring %sel2 is object selectionCriterion for longstring %sel = OR(LT(this, 'C'), EQ(this, 'Taurus')) %sel2 = EQ(this, 'Taurus') print %k:findNextitem(%sel) print %k:findPreviousitem(%sel2)

The result is:

Aries CANCELLING REQUEST: MSIR.0750: Class UnicodeNamedArraylist, function FindPreviousItem: ItemNotFound exception: no items match SelectionCriterion in line 18

See also

  • FindPreviousItem is identical to FindNextItem except that it searches backward in the FloatNamedArraylist, NamedArraylist, or UnicodeNamedArraylist.