111 lines
2.8 KiB
Java
111 lines
2.8 KiB
Java
//: patterns/trashvisitor/TrashVisitor.java
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// The "visitor" pattern.
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package patterns.trashvisitor;
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import patterns.trash.*;
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import java.util.*;
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// Specific group of algorithms packaged
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// in each implementation of Visitor:
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class PriceVisitor implements Visitor {
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private double alSum; // Aluminum
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private double pSum; // Paper
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private double gSum; // Glass
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private double cSum; // Cardboard
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@Override
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public void visit(VAluminum al) {
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double v = al.weight() * al.value();
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System.out.println(
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"value of Aluminum= " + v);
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alSum += v;
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}
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@Override
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public void visit(VPaper p) {
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double v = p.weight() * p.value();
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System.out.println(
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"value of Paper= " + v);
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pSum += v;
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}
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@Override
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public void visit(VGlass g) {
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double v = g.weight() * g.value();
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System.out.println(
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"value of Glass= " + v);
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gSum += v;
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}
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@Override
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public void visit(VCardboard c) {
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double v = c.weight() * c.value();
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System.out.println(
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"value of Cardboard = " + v);
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cSum += v;
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}
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void total() {
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System.out.println(
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"Total Aluminum: $" + alSum + "\n" +
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"Total Paper: $" + pSum + "\n" +
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"Total Glass: $" + gSum + "\n" +
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"Total Cardboard: $" + cSum);
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}
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}
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class WeightVisitor implements Visitor {
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private double alSum; // Aluminum
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private double pSum; // Paper
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private double gSum; // Glass
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private double cSum; // Cardboard
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@Override
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public void visit(VAluminum al) {
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alSum += al.weight();
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System.out.println("weight of Aluminum = "
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+ al.weight());
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}
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@Override
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public void visit(VPaper p) {
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pSum += p.weight();
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System.out.println("weight of Paper = "
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+ p.weight());
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}
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@Override
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public void visit(VGlass g) {
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gSum += g.weight();
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System.out.println("weight of Glass = "
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+ g.weight());
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}
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@Override
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public void visit(VCardboard c) {
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cSum += c.weight();
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System.out.println("weight of Cardboard = "
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+ c.weight());
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}
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void total() {
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System.out.println("Total weight Aluminum:"
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+ alSum);
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System.out.println("Total weight Paper:"
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+ pSum);
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System.out.println("Total weight Glass:"
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+ gSum);
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System.out.println("Total weight Cardboard:"
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+ cSum);
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}
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}
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public class TrashVisitor {
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public static void main(String[] args) {
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ArrayList bin = new ArrayList();
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// ParseTrash still works, without changes:
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ParseTrash.fillBin("VTrash.dat", bin);
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// You could even iterate through
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// a list of visitors!
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PriceVisitor pv = new PriceVisitor();
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WeightVisitor wv = new WeightVisitor();
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Iterator it = bin.iterator();
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while(it.hasNext()) {
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Visitable v = (Visitable)it.next();
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v.accept(pv);
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v.accept(wv);
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}
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pv.total();
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wv.total();
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}
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} ///:~
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