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POOverride a method and make it behave static
 

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    <p>I have an existing framework, which I can't change, it reads 2 properties</p> <ul> <li><code>ClassA=somepackage.AnImplementationOfInterfaceA</code></li> <li><code>ClassB=somepackage.AnImplementationOfInterfaceB</code></li> </ul> <p>Which calls <code>public methodA</code> on a <code>new ClassA()</code>, <code>public methodB</code> on a <code>new ClassB()</code> in that order</p> <p>I want to make a <code>class C</code> which implements interfaces A, B and provides hooks <code>methodC1</code>, <code>methodC2</code> for <code>class D</code> to override (<code>methodA</code> &amp; <code>methodB</code> contain a lot of boilerplate and complex to implement - <code>methodC1</code> &amp; <code>methodC2</code> would encapsulate the business logic) . Then my properties would be</p> <ul> <li><code>ClassA=somepackage.classD</code> </li> <li><code>ClassB=somepackage.classD</code></li> </ul> <p>The problem is that the person who implements class D might be tempted to write something like:</p> <pre><code>class D extends class C { private int foo; //must be non-static due to multi-threaded new Class D() calls going on int methodC1() {this.foo = read number from network} methodC2(int x) {y = this.foo;} //methodC2 is always called after methodC1 //methodA, methodB implementation inherited from C } </code></pre> <p>But this wouldn't work as expected since the framework would actually create a new object of <code>class D</code> each time before invoking <code>methodA</code>, <code>methodB</code> and thus can't rely on using the "this" reference.</p> <p>Defining <code>methodC1</code>, <code>methodC2</code> as <code>static</code> wouldn't work either because then the call to <code>methodC1</code> is tied to the implementation in <code>C</code>, not the overriden one in <code>D</code>. </p> <p>When really what ought to be written is:</p> <pre><code>class D extends class C { int methodC1() {return number from network;} methodC2(int x) {y = x} //here y is using the return value of methodC1 //methodA, methodB implementation inherited from C } </code></pre> <p>I would also like <em>only</em> <code>methodC1</code>, <code>methodC2</code> to be overridable i.e. programmers working on D can't mess with <code>methodA</code></p> <p>The ideal design would have</p> <ul> <li>the properties refer to one class only</li> <li><code>methodC1</code>, <code>methodC2</code> to be in that class</li> </ul> <p>Summary of challenges</p> <ul> <li>no <code>this</code> in <code>methodC1</code>, <code>methodC2</code></li> <li>can't make <code>methodC1</code>, <code>methodC2</code> <code>static</code></li> <li>properies takes only a instantiable class</li> </ul> <p>How do I design this framework? Is this even solvable? You can change the signature of <code>methodC1</code>, <code>methodC2</code>.</p>
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    1. USsatish b
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    1. COYou can not make static methods overridable.
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      1. USBhavik Ambani
    2. COYes. The crux of my design problem seems to be restricting a method from using "this" but making it overridable.
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      1. USsatish b
 

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