Am I getting this right? I'm not completely sure on Serialization as it seems others not just me have struggled with this but I can hope at least I've got the theory right.

Implements

• Interface - like a contract programmer signs when they add to the list of interfaces that the class implements.

• It's a guarantee from the programmer. The programmer then has to work out how to keep that guarantee or program fails to compile.

• "implements" are added to a class. You use the implements keyword and specify the name of the interface. A common example is Comparable.

public class NameofClass implements Comparable {

}

• You can check your code meets the "contract" by using instanceof.

Comparable is a keyword that tells the class that it needs a certain method to compare one object to another and that it should return an integer. and that should return an integer that denotes whether it is less than, equal to, or greater than the object passed in as a parameter.

Comparable does is tell every class that implements it that it has to have a compareTo method that takes in another object of the same type, and that should return an integer that denotes whether it is less than, equal to, or greater than the object passed in as a parameter

So the code now is expecting the programmer to override an abstract method from Object, i.e. the compareTo() method. As far as I'm aware this is the only method you can do this with.

need to include a method called compareTo. The implements keyword is comparable so need to compare the method/definition.

From the documentation

• int compareTo(T o)

• T = the type of iobjects that this object may be compared to

• o = object to be compared

• It either returns a negative, zero or positive.

• You can have multiple interfaces defined in a class (comma separated)

We use @override annotation in the same way as overriding a normal method. Here we're overriding an implementation.

Code Example

public int compareTo(Object obj) { 
   //write code
}

public int compareTo(Object obj) {
  Treet other = (Treet) obj;
  if (equal(other)) {
     return 0;
  }

  int dateCmp = mCreationDate.compareTo(other.mCreationDate);

  if(dateCmp == 0) {
     return mDescription.compareTo(other.mDescription);
  }

   return dateCmp;
}

Interface lists - http://docs.oracle.com/javase/8/docs/api/

Serialization

Serialization - https://teamtreehouse.com/library/java-data-structures/organizing-data/serialization

• is the process of translating objects into a format that can be stored and recreated.

• Ever wanted to save an object for later after the program is done running. Well this is called serialization.

• Serialization is taking an object and storing its representation in a state that can be loaded.

• Serialization requires that the object implements the serialization interface which doesn't have any required methods.

It's a "marker" interface, an interface that is marked with an ability lijk the ability to be serialized.

import java.io.Serializable;

public class ClassName implements Comparable, Serializable. <--- class is now serializable.

Can run little methods on it like save();