![]() To solve this problem, javac adds additional synthetic accessor methods to Outer to allow access. The purpose of the Nestmates JEP is to generalize and formalize this symbiotic relationship between types, and to clean up the current implementation, which has a certain amount of technical debt and is rather hacky to modern eyes.Īs of Java 10, nested classes are compiled into separate top-level classfiles, but with a special naming convention, so that a nested class Nested within a class Outer is compiled into a file named Outer$Nested.class The problem with this implementing strategy is that according to the rules of the Java language, a nested class has access to all the members of the enclosing class, including private members. This means that they don’t really have a completely independent existence as an entity, and only live in coexistence with another type. This means that nested types have privileged access and can be thought of as "slightly bending the rules of encapsulation".Īnother way of thinking about this use case of nested types is that they are types that are somehow tied together with another type. Outer outer new Outer () Outer.Inner inner outer.new Inner () inner.printText () Inner Class Shadowing If a Java inner class declares fields or methods with the same names as field or methods in its enclosing class, the inner fields or methods are said to shadow over the outer fields or methods. member) type, it has access in the same way that member variables and methods do. Second, a type may be nested because it needs especially intimate access to the internals of another type. In practice, with the advent of Java 8, this use case has substantially been taken over by lambda expressions and the use of anonymous types as closely-localized types has dramatically declined, although it still persists for some cases. In older versions of Java, the only way to do this was with a nested type, such as an anonymous implementation of an interface. This means that it should be tightly localized, as it is really part of the implementation detail. First, a type may be only required for a very specific reason, and in a very small section of code. In general, nested types are used for two separate purposes, both related to encapsulation. The new feature is connected to the implementation of Java's nested classes (which are often loosely referred to as "inner classes", despite this being only one possible type of nested class). ![]() This is a technical enhancement to the platform that pays off a 20 year old architectural debt introduced in Java 1.1 If inner classes are used each component gets its own event handler and each event handler implicitly knows the component it is working for.Oracle has announced JEP 181 - "Nest-based Access Control" - aka "Nestmates". The advantage of using inner class for event handling mechanism is that the use of if/else to select the component to be handled can be avoided. Inner classes are best used in the event handling mechanism and to implement the helper classes. Advantage of writing the inner class B in the class A is you can avoid having a separate class. One way is to write a separate class B or to write an inner class B inside class A. If a class A is written requires another class B for its own use, there are two ways to do this. This increases the level of encapsulation. Nesting the inner class code where it is used (inside the outer class) makes the code more readable and maintainable. So the outer class members which are going to be used by the inner class can be made private and the inner class members can be hidden from the classes in the same package. the inner class has access to all members of the outer class and still have its own type is the main advantages of Inner class.Īdvantage of inner class is that they can be hidden from the other classes in the same package and still have the access to all the members (private also) of the enclosing class. The inner class shares a special relationship with the outer class i.e. Nesting the inner class code where it is used (inside the outer class) makes the code more readable and maintainable. the outer class makes the package more streamlined. ![]() The embedding of inner class into the outer class in the case when the inner class is to be used only by one class i.e.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |