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Designing good classes
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* To guide design on the class level, ask: "How will this class be used?"
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* A class should represent one coherent abstraction or concept.
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* Look for code reuse opportunities (would this class be useful elsewhere?)
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* When working with a class externally, you should not have to understand the internal implementation.
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* Every constructor and public method should leave the instance variables in a consistent and correct state for the next public method call.
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* Generally avoid going over 7 (plus or minus 2) instance variables in a class.
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* Do not repeat data unless truly necessary.
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* Do not give variables more scope than they require.
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Immutable objects
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Benefits:
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Thread-safe
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Can freely share pointers to objects; no hidden side effects if something changes
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Drawback:
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If there are lots of changes then immutability may result in memory burn and slowdowns
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