定義
對於物件 Obj 的一個方法 fun() 而言， fun() 只能存取以下類型的物件：
- 自己或父類別的方法（to itself (Obj itself). You can play with yourself.）
- 自己或父類屬性中的其他物件（to objects contained in attributes of itself or a superclass (Obj’s direct component objects). You can play with your own toys.）
- 方法可以使用參數傳進來的物件（to an object that is passed as a parameter to the method (fun’s parameters). You can play with toys that were given to you.）
- 使用自己所創造出來的物件（to an object that is created by the method (Any objects created/instantiated within fun). And you can play with toys you’ve made yourself.）
- 全域變數中的物件（to an object that is stored in a global variable.）
範例
/* Class A */
public class A {
private int a1;
C c;
F f;
G g = new G();
public A(C c) { // LoD 1
this.c = c;
}
public void useSelf() { // LoD 1
go();
}
public void go() { // 沒有符合任何LoD，因為僅print且無使用object。
System.out.println("A go");
}
public void setA1(int a1) { // LoD 1
this.a1 = a1;
}
public int getA1() { // 沒有符合任何LoD，因為僅回傳而已。
return this.a1;
}
public void setC(C c) { // LoD 1
this.c = c;
}
public C getC() { // 沒有符合任何LoD，因為僅回傳而已。
return c;
}
private void useC() { // LoD 2
System.out.println(c);
c.go();
}
public void useE(E e) { // LoD 3
e.go();
}
public void useD() { // LoD 4
D d = new D();
d.go();
}
public void useF() { // LoD 4
f = new F();
f.go()
}
public void useG() { // LoD 4
g.go();
}
}
/* Class B */
public class B extends A {
public B(C c) {
super(c);
}
public void useSuperclassAttributeC() { // LoD 2
c.go();
}
public void useSuperclassAttributeG() { // LoD 2
g.go();
}
}
/* Class C */
public class C {
public void go() {
System.out.println("C go");
}
}
/* Class D */
public class D {
public void go() {
System.out.println("D go");
}
}
/* Class E */
public class E {
public void go() {
System.out.println("E go");
}
}
/* Class F */
public class F {
public void go() {
System.out.println("F go");
}
}
/* Class G */
public class G {
public void go() {
System.out.println("G go");
}
}
