A question about inner classes

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#711

From: Carlos Zin
Date: Thu, 02 Dec 2004 23:41

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Please suppose I have the following case where Tool is a class defined 
somewhere else:

public class ToolFactory {

    private class A extends Tool {}

    private class B extends Tool {}

    public static Tool makeTool(String toolName) {
        if (toolName == "A")
            return new A();
        else if (toolName == "B")
            return new B();
        else
            return null;
    }
}

I am trying to build a static factory method named "makeTool()" which 
produces instances of classes A and B but the compiler complain telling that 
non-static variable this cannot be referenced from a static context.

Making the method non-static eliminate the error but then I need to make an 
instance of Toolfactory in order to access method makeTool(s) which is not 
what I want. I need to call "ToolFactory.makeTool(s)", i.e. a static method 
with no object instance.
How can I solve this problem?

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Subject: A question about inner classes
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