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POWhat are the best practices for determining the tasks of Constructor, Initialization and Reset methods
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  1. POWhat are the best practices for determining the tasks of Constructor, Initialization and Reset methods
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    copied!<p>This is a general OOP question although I am designing in Java. I'm not trying to solve a particular problem, just to think through some design principles.<br> From my experience I have reached the habit segregating object setup into three phases.</p> <p>The goal is to minimize: extra work, obfuscated code and crippled extensibility.</p> <p><br><b>Construction</b><br></p> <ol> <li>The minimal actions necessary to create a valid Object, passes an existence test</li> <li>Instantiate and initialize only "one time", never to be over-ridden, non variable objects that will not change/vary for the life of the Object</li> <li>Initialize final members</li> <li>Essentially a runtime stub </li> </ol> <p><strong>Initialization</strong></p> <ol> <li>Make the Object useful</li> <li>Instantiate and initialize publicly accessible members</li> <li>Instantiate and initialize private members that are variable values</li> <li>Object should now pass external tests with out generating exceptions (assuming code is correct)</li> </ol> <p><strong>Reset</strong></p> <ol> <li>Does not instantiate anything</li> <li>Assigns default values to all variable public/private members </li> <li>returns the Object to an exact state</li> </ol> <p>A Toy example:</p> <pre><code>public class TestObject { private int priv_a; private final int priv_b; private static int priv_c; private static final int priv_d = 4; private Integer priv_aI; private final Integer priv_bI; private static Integer priv_cI; private static final Integer priv_dI = 4; public int pub_a; public final int pub_b; public static int pub_c; public static final int pub_d = 4; public Integer pub_aI; public final Integer pub_bI; public static Integer pub_cI; public static final Integer pub_dI = 4; TestObject(){ priv_b = 2; priv_bI = new Integer(2); pub_b = 2; pub_bI = new Integer(2); } public void init() { priv_a = 1; priv_c = 3; priv_aI = new Integer(1); priv_cI = new Integer(3); pub_a = 1; pub_c = 3; pub_aI = new Integer(1); pub_cI = new Integer(3); } public void reset() { priv_a = 1; priv_c = 3; priv_aI = 1; priv_cI = 3; pub_a = 1; pub_c = 3; pub_aI = 1; pub_cI = 3; } } </code></pre>
 

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