Kotlin vs Java continued...
Classes that are used exclusively for data are called data classes and declared with the data keyword.
The compiler automatically creates methods such as equals(), hashcode(), toString(), copy(). These are formed based on the type parameters in the constructor. These classes come with a few restrictions such as they cannot be abstract, sealed or inner but some of these were even relaxed in versions subsequent to 1.1
The standard library provides Pair and Triple as data classes.
Kotlin is perhaps the first to provide a clean separation between readonly and mutable collections. The readonly provides an interface to the collection to access the elements of items. The mutable interface extends the read only interface with write access. This is makes it clearer to call out collections that are meant for reporting stacks and do not interfere with the operations ongoing with the existing collection.
Kotlin is therefore, more than a notation change from Java. It packs features that were not seen earlier with Java.
The delegation pattern is a newer technique which allows a class Derived to implement an interface Base by delegating all of its public members to a specified object. Since the base implements the interface, the public methods are all available on the base. The derived object merely delegates it to the base. This delegation pattern has first class citizenship in the Kotlin language.
The class Derived also has the ability to override any delegation. It can do this on a method by method basis. Kotlin provides this ability to use class Derived independent from the Base. The delegate object has no visibility to the overridden methods. This behavior is valid for properties on the Derived class as well.
Classes that are used exclusively for data are called data classes and declared with the data keyword.
The compiler automatically creates methods such as equals(), hashcode(), toString(), copy(). These are formed based on the type parameters in the constructor. These classes come with a few restrictions such as they cannot be abstract, sealed or inner but some of these were even relaxed in versions subsequent to 1.1
The standard library provides Pair and Triple as data classes.
Kotlin is perhaps the first to provide a clean separation between readonly and mutable collections. The readonly provides an interface to the collection to access the elements of items. The mutable interface extends the read only interface with write access. This is makes it clearer to call out collections that are meant for reporting stacks and do not interfere with the operations ongoing with the existing collection.
Kotlin is therefore, more than a notation change from Java. It packs features that were not seen earlier with Java.
The delegation pattern is a newer technique which allows a class Derived to implement an interface Base by delegating all of its public members to a specified object. Since the base implements the interface, the public methods are all available on the base. The derived object merely delegates it to the base. This delegation pattern has first class citizenship in the Kotlin language.
The class Derived also has the ability to override any delegation. It can do this on a method by method basis. Kotlin provides this ability to use class Derived independent from the Base. The delegate object has no visibility to the overridden methods. This behavior is valid for properties on the Derived class as well.
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