Inappropriate Intimacy #
Penjelasan Smell #
Smell ini terjadi karena hubungan antar class yang terlalu intim, menyebabkan class yang satu mengeksploitasi internal field dan/atau method di class lain.
Hal ini berbahaya karena class yang internal logic-nya diakses bisa mendapat perlakuan yang tidak terduga.
Pada constructor di Product.java, class Product mengetahui ada fungsi addTag di Catalog dan menambahkan tag-nya sendiri ke Catalog.
java
public class Product {
private Catalog catalog;
private UUID id;
private String name;
private double price;
public Product(String name, double price, Catalog catalog) {
this.id = UUID.randomUUID();
this.name = name;
this.price = price;
this.catalog = catalog;
this.catalog.addTag(this, Catalog.NEWCOMER_TAG);
}
// ...
}
java
public class Catalog {
public final static String NEWCOMER_TAG = "newcomer";
public final static String CHEAP_TAG = "cheap";
private String name;
private Vector<Product> products;
private Map<UUID, Vector<String>> tags;
public Catalog(String name) {
this.name = name;
this.products = new Vector<Product>();
this.tags = new HashMap<UUID, Vector<String>>();
}
public void print() {
System.out.println("catalog " + name + ":");
for (Product product : products) {
String line = "";
line += product.getId() + " ";
line += product.getName() + " ";
line += product.getPrice() + " ";
Vector<String> tags = this.tags.get(product.getId());
if(tags != null) {
line += String.join(",", tags);
}
System.out.println(line);
}
}
public void addTag(Product p, String tag) {
Vector<String> tags = this.tags.get(p.getId());
if(tags == null) {
tags = new Vector<String>();
}
if(tags.contains(tag)) return;
tags.add(tag);
this.tags.put(p.getId(), tags);
}
public void removeTag(Product p, String tag) {
Vector<String> tags = this.tags.get(p.getId());
if(tags == null) {
return;
}
while(tags.remove(tag)) {}
this.tags.put(p.getId(), tags);
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public void addProduct(Product p) {
products.add(p);
newcomerTag();
cheapTag();
}
/**
* give newcomer tag to the 3 latest product
*/
public void newcomerTag() {
int n = products.size();
if(n > 3) {
for(int i = 0; i < n-3; i++) {
removeTag(products.elementAt(i), NEWCOMER_TAG);
}
}
int start = n-3 > 0 ? n-3 : 0;
for(int i = start; i < n; i++) {
addTag(products.elementAt(i), NEWCOMER_TAG);
}
}
/**
* give cheap tag to top 3 cheapest product
*/
public void cheapTag() {
Vector<Product> sortByPrice = (Vector<Product>) products.clone();
sortByPrice.sort(new Comparator<Product>() {
@Override
public int compare(Product o1, Product o2) {
if(o1.getPrice() == o2.getPrice()) return 0;
if(o1.getPrice() < o2.getPrice()) return -1;
return 1;
}
});
for (Product product : sortByPrice) {
removeTag(product, CHEAP_TAG);
}
int n = sortByPrice.size() > 3 ? 3 : sortByPrice.size();
for(int i = 0; i < n; i++) {
addTag(sortByPrice.elementAt(i), CHEAP_TAG);
}
}
}
Hal ini tentu berbahaya karena artinya, class Product bisa menambahkan tag apapun tanpa seizin Catalog.
Penyelesaian #
Catalog dan Product punya hubungan bidirectional yang tidak perlu, maka dilakukan Change Bidirectional Association to Unidirectional. Dengan cara menghapus field catalog di dalam Product.
Semua method di class Catalog yang berhubungan dengan manipulasi tag access modifier-nya diubah menjadi private.
java
public class Product {
private UUID id;
private String name;
private double price;
public Product(String name, double price) {
this.id = UUID.randomUUID();
this.name = name;
this.price = price;
}
public UUID getId() {
return id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
}
java
public class Catalog {
public final static String NEWCOMER_TAG = "newcomer";
public final static String CHEAP_TAG = "cheap";
private String name;
private Vector<Product> products;
private Map<UUID, Vector<String>> tags;
public Catalog(String name) {
this.name = name;
this.products = new Vector<Product>();
this.tags = new HashMap<UUID, Vector<String>>();
}
public void print() {
System.out.println("catalog " + name + ":");
for (Product product : products) {
String line = "";
line += product.getId() + " ";
line += product.getName() + " ";
line += product.getPrice() + " ";
Vector<String> tags = this.tags.get(product.getId());
if(tags != null) {
line += String.join(",", tags);
}
System.out.println(line);
}
}
private void addTag(Product p, String tag) {
Vector<String> tags = this.tags.get(p.getId());
if(tags == null) {
tags = new Vector<String>();
}
if(tags.contains(tag)) return;
tags.add(tag);
this.tags.put(p.getId(), tags);
}
private void removeTag(Product p, String tag) {
Vector<String> tags = this.tags.get(p.getId());
if(tags == null) {
return;
}
while(tags.remove(tag)) {}
this.tags.put(p.getId(), tags);
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public void addProduct(Product p) {
products.add(p);
newcomerTag();
cheapTag();
}
/**
* give newcomer tag to the 3 latest product
*/
private void newcomerTag() {
int n = products.size();
if(n > 3) {
for(int i = 0; i < n-3; i++) {
removeTag(products.elementAt(i), NEWCOMER_TAG);
}
}
int start = n-3 > 0 ? n-3 : 0;
for(int i = start; i < n; i++) {
addTag(products.elementAt(i), NEWCOMER_TAG);
}
}
/**
* give cheap tag to top 3 cheapest product
*/
private void cheapTag() {
Vector<Product> sortByPrice = (Vector<Product>) products.clone();
sortByPrice.sort(new Comparator<Product>() {
@Override
public int compare(Product o1, Product o2) {
if(o1.getPrice() == o2.getPrice()) return 0;
if(o1.getPrice() < o2.getPrice()) return -1;
return 1;
}
});
for (Product product : sortByPrice) {
removeTag(product, CHEAP_TAG);
}
int n = sortByPrice.size() > 3 ? 3 : sortByPrice.size();
for(int i = 0; i < n; i++) {
addTag(sortByPrice.elementAt(i), CHEAP_TAG);
}
}
}