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POdesign build or factory pattern
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  1. POdesign build or factory pattern
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    copied!<p>I understand both patterns (I think), but given my specific need I can't seem to either find a solution or find an example (all examples are really simple).</p> <p>My problem is that I want some kind of factory (or director/etc) that creates objects that may or may not have dependencies.</p> <p>Let's suppose I have this code: (I'm using C#)</p> <pre><code>interface MyObject{ public void load(); public void update(); public void draw(); } class ObjectA : MyObject{ public void load(){/*load*/} public void update(){/*update*/} public void draw(){/*draw*/} } class ObjectB : MyObject{ Texture texture; public ObjectB(Content content){ texture = content.load("texture"); } public void load(){/*load*/} public void update(){/*update*/} public void draw(){/*draw*/} } class ObjectC : MyObject{ Parent parent; public void setParent(Parent parent){ this.parent = parent; } public void load(){/*load*/} public void update(){ if( this.status == Status.Done ){ parent.remove(this); } } public void draw(){/*draw*/} } class Map : Parent{ MyObject myobj; public void load(MapInfo map){ //This is what I want to achieve myobj = MyObjectFactory.create(map.objectInfo); //This is my problem. I don't really know how to solve this. //I can't do this &gt; myobj.setParent(this); //error //Unless I create a setParent method in interface, I don't know how to achieve this. } public void remove(MyObject obj){/*remove*/} } </code></pre> <p><strong>I don't really know how to achieve this: <code>myobj.setParent(this);</code>. It cannot be in the constructor (like ObjectB), because Parent is not the same for every situation.</strong></p> <p>This is what I would have for my factory:</p> <pre><code>class MyObjectFactory{ Content content; public MyObjectFactory(Content content){ this.content = content; } public MyObject create(objectInfo){ //suppose objectInfo is xml //read xml Type type = objectInfo.type; //I'm totally fine with this. (Noob implementation) switch(type){ case Type.A: return new ObjectA(); break; case Type.B: //I'm also fine with this, unless there is a better way. return new ObjectB(this.content); break; case Type.C: return new ObjectC(); break; } } } </code></pre> <p>So far ObjectA and ObjectB are good. ObjectA is simple. ObjectB constructor gets set by Factory (Factory was previously given <code>content</code> variable).</p> <p>That leaves ObjectC, which needs Parent to remove itself (it may not be the best example. Trying to simulate different needs). <strong>How do I achieve this?</strong></p> <p>I only came up with one solution: Add a method to MyObject interface, ObjectA and ObjectB would have just a setParent method that does nothing.</p> <p>I hope this is not confusing.</p> <p><strong>Edit</strong> I forgot to add Parent in: <code>class Map : Parent</code></p>
 

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