ede3954d86
See notes in "Foreword to the Leanpub Edition"
32 lines
979 B
Java
32 lines
979 B
Java
// patterns/trash/Visitor.java
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// (c)2021 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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// The base class for Visitors.
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package patterns.trash;
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public abstract class Visitor {
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protected double alTotal; // Aluminum
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protected double pTotal; // Paper
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protected double gTotal; // Glass
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protected double cTotal; // Cardboard
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protected String descriptor;
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protected Visitor(String descriptor) {
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this.descriptor = descriptor;
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}
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protected void show(String type, double value) {
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System.out.printf(
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"%s %s: %.2f%n", type, descriptor, value);
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}
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public void total() {
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show("Total Aluminum", alTotal);
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show("Total Paper", pTotal);
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show("Total Glass", gTotal);
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show("Total Cardboard", cTotal);
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}
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abstract void visit(Aluminum a);
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abstract void visit(Paper p);
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abstract void visit(Glass g);
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abstract void visit(Cardboard c);
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}
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