Bruce Eckel 49edcc8b17 reorg
2015-06-15 17:47:35 -07:00

122 lines
3.3 KiB
Java

//: patterns/trashvisitor/TrashVisitor.java
// ©2015 MindView LLC: see Copyright.txt
// The "visitor" pattern.
package patterns.trashvisitor;
import patterns.trash.*;
import java.util.*;
import static com.mindviewinc.util.Print.*;
// Specific group of algorithms packaged
// in each implementation of Visitor:
class PriceVisitor implements Visitor {
private double alSum; // Aluminum
private double pSum; // Paper
private double gSum; // Glass
private double cSum; // Cardboard
@Override
public void visit(VAluminum al) {
double v = al.weight() * al.value();
print("value of Aluminum= " + v);
alSum += v;
}
@Override
public void visit(VPaper p) {
double v = p.weight() * p.value();
print("value of Paper= " + v);
pSum += v;
}
@Override
public void visit(VGlass g) {
double v = g.weight() * g.value();
print("value of Glass= " + v);
gSum += v;
}
@Override
public void visit(VCardboard c) {
double v = c.weight() * c.value();
print("value of Cardboard = " + v);
cSum += v;
}
void total() {
print(
"Total Aluminum: $" + alSum + "\n" +
"Total Paper: $" + pSum + "\n" +
"Total Glass: $" + gSum + "\n" +
"Total Cardboard: $" + cSum);
}
}
class WeightVisitor implements Visitor {
private double alSum; // Aluminum
private double pSum; // Paper
private double gSum; // Glass
private double cSum; // Cardboard
@Override
public void visit(VAluminum al) {
alSum += al.weight();
print("Aluminum weight = " + al.weight());
}
@Override
public void visit(VPaper p) {
pSum += p.weight();
print("Paper weight = " + p.weight());
}
@Override
public void visit(VGlass g) {
gSum += g.weight();
print("Glass weight = " + g.weight());
}
@Override
public void visit(VCardboard c) {
cSum += c.weight();
print("Cardboard weight = " + c.weight());
}
void total() {
print("Total weight Aluminum:" + alSum);
print("Total weight Paper:" + pSum);
print("Total weight Glass:" + gSum);
print("Total weight Cardboard:" + cSum);
}
}
public class TrashVisitor {
public static void main(String[] args) {
ArrayList<Trash> bin = new ArrayList<>();
// ParseTrash still works, without changes:
ParseTrash.fillBin("VTrash.dat", bin);
// You could even iterate through
// a list of visitors!
PriceVisitor pv = new PriceVisitor();
WeightVisitor wv = new WeightVisitor();
for(Trash aBin : bin) {
Visitable v = (Visitable) aBin;
v.accept(pv);
v.accept(wv);
}
pv.total();
wv.total();
}
} /* Output: (First and last 10 Lines)
Loading patterns.trashvisitor.VGlass
Loading patterns.trashvisitor.VPaper
Loading patterns.trashvisitor.VAluminum
Loading patterns.trashvisitor.VCardboard
value of Glass= 12.420000225305557
Glass weight = 54.0
value of Paper= 2.2000000327825546
Paper weight = 22.0
value of Paper= 1.1000000163912773
Paper weight = 11.0
________...________...________...________...________
value of Cardboard = 5.060000091791153
Cardboard weight = 22.0
Total Aluminum: $860.0499778985977
Total Paper: $35.80000053346157
Total Glass: $150.1900027245283
Total Cardboard: $40.02000072598457
Total weight Aluminum:515.0
Total weight Paper:358.0
Total weight Glass:653.0
Total weight Cardboard:174.0
*///:~