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    <p><em>Assuming that there are a number of places where you legitimately need to deal with processing Circle and Square independently,</em> I would deal with the heterogeneous collection by applying the <a href="http://en.wikipedia.org/wiki/Visitor_pattern" rel="nofollow">Visitor Pattern</a></p> <p>This has the benefit that if you add Triangle later, then when you add a method <code>T visitTriangle(Triangle triangle);</code> to the visitor, your code won't compile until you update every single visitor, avoiding nasty runtime surprises.</p> <p>However... if you're really only talking about a single instance of processing Circle and Square differently, then applying Visitor here is overkill and I would just consider adding an abstract method to Shape for <code>doSomeSpecificUiThing()</code>.</p> <p>It would look something like this:</p> <pre><code>class ShapeVisitor&lt;T&gt; { T visitCircle(Circle circle); T visitSquare(Square square); } class Shape { abstract &lt;T&gt; T accept(ShapeVisitor&lt;T&gt; visitor); // methods of Class Shape } class Circle extends Shape { &lt;T&gt; T accept(ShapeVisitor&lt;T&gt; visitor) { return visitor.visitCircle(this); } // methods of Class Circle } class Square extends Shape { &lt;T&gt; T accept(ShapeVisitor&lt;T&gt; visitor) { return visitor.visitSquare(this); } // methods of Class Square } Class Canvas { void drawAll() { for (Shape s : heterogeneousCollection) { s.draw(); s.accept(new ShapeVisitor&lt;Void&gt;() { @Override Void visitCircle(Circle circle) { circle.xyz(); return null; } @Override Void visitSquare(Square square) { square.abc(); return null; } } } } } </code></pre>
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    1. POCollections of different types inherited from a single object vs a single collection of super object
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    1. USMichael D
    1. USMichael D
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    1. COThanks a lot for your response. I will try to read more about visitor patter.
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      1. USGopal
    2. COOk now that I got nice answer, I would like to share that iBatis does support inheritance mapping. This is possible using "discriminator" and "subtype" attributes of a resultMap. A close read at documentation can be of more help.
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