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<div><font size="2">I'm going through the Drools documentation regarding the use of lists and other collections. I want to make sure my understanding is correct.</font></div>
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<div><font size="2">So if I have a class:</font></div>
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<div><font face="Courier New, monospace" size="2">public class Foo {</font></div>
<div><font face="Courier New, monospace" size="2"> </font></div>
<div><font face="Courier New, monospace" size="2"> private int x;</font></div>
<div><font face="Courier New, monospace" size="2"> private int y;</font></div>
<div><font face="Courier New, monospace" size="2"> private List<String> names = ArrayList<String>();</font></div>
<div><font face="Courier New, monospace" size="2"> </font></div>
<div><font face="Courier New, monospace" size="2"> public List<String> getNames() {return names;}</font></div>
<div><font face="Courier New, monospace" size="2"> </font></div>
<div><font face="Courier New, monospace" size="2"> // appropriate getters/setters for the int fields ...</font></div>
<div><font face="Courier New, monospace" size="2">}</font></div>
<div><font face="Courier New, monospace" size="2"> </font></div>
<div><font size="2">With this I can insert a Foo object into working memory. I can even make the int fields dynamic facts with the appropriate addition of "bean-ifying" code.</font></div>
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<div><font size="2">For the List, however, I need to insert it separately into working memory in order to make use of Drools' rule language ('contains' ,etc.)? I'm assuming that doesn't come free because I have to insert my own custom class objects if they
are included via composition in a larger fact!</font></div>
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<div><font size="2">Also, I'm guessing the Collection type classes cannot be dynamic facts? Meaning if I modify my List with add, remove, clear, etc., I must explicitly call update in my code on the List fact in order to alert Drools to a change in the List,
correct? </font></div>
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<div><font size="2">So then the question also comes up as to how I would write a rule that looks for all instances of Strings in the List that match against a given regex expression. I've not been successful at figuring this out...</font></div>
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<div><font face="Courier New, monospace" size="2">Rule "when a Foo List is modified, get all Strings in it that start with 'error'"</font></div>
<div><font face="Courier New, monospace" size="2">when</font></div>
<div><font face="Courier New, monospace" size="2"> $foo : Foo($names : names)</font></div>
<div><font face="Courier New, monospace" size="2"> $foundThese : ArrayList() from collect(??? matches "error.*" from $names)</font></div>
<div><font face="Courier New, monospace" size="2">then</font></div>
<div><font face="Courier New, monospace" size="2"> // act on $foo and $foundThese</font></div>
<div><font face="Courier New, monospace" size="2"> </font></div>
<div><font size="2">I know that rule is NOT correct, but I'm not sure how I'm supposed to access an immutable object inside a collection. The examples in the documentation show how to get at mutable class objects.</font></div>
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<div><font size="2">Thanks!</font></div>
<div><font size="2">-Allen</font></div>
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