52 lines
1.3 KiB
Java
52 lines
1.3 KiB
Java
Simple Inheritance
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public class SimpleInheritance /* implicitly inherits from Object class */ {
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// available to subclass and package level clients
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protected int balance;
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public SimpleInheritance( String str ) {
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System.out.println( "SimpleInheritance says: " + str );
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}
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public void message() {
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}
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}
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class MySubclass extends SimpleInheritance {
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// must define constructor because parent class
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// does not define a default constructor
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public MySubclass( String str ) {
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// call the parent class's constructor
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super( str );
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}
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// i've overriden the message method declared within SimpleInheritance
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public void message() {
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// but can call it by using the super keyword
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super.message();
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// i can also access non-private implementation, best not to have any
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// in the first place, and expose through controlled accessor methods
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System.out.println( super.balance );
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}
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}
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class PackageLevelClient {
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public PackageLevelClient() {
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SimpleInheritance is = new MySubclass( "yo" );
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// nasty, as a class in the package i can access
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// all protected variables defined within this package,
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// even though i'm not a part of the inheritance tree
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// yuk, yuk, yuk, yuk!!!!!!!!!!
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is.balance = 45;
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}
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}
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