Practice with Interfaces

Practice: String Length Comparable Parameterized

Created By: Geoffrey Challen

/ Version: 2021.10.0

Create a public class named MyString. MyString should provide a public constructor that accepts a single String argument. You should reject null Strings in your constructor using assert.

MyString should also implement the Java Comparable<MyString> interface, returning 1 for a positive result and -1 for a negative result. Normally Strings are compared lexicographically: "aaa" comes before "z". MyString should compare instances based on the length of its stored String. So MyString("aaa") should come after MyString("z"), since "aaa" is longer than "z".

You will probably need to review the documentation for Comparable. Because we are using the type parameter MyString to the Comparable interface, compareTo accepts an MyString as an argument. The MyString passed to compareTo will not be null.

Practice: Both Greater Comparable

Created By: Geoffrey Challen

/ Version: 2021.10.0

Create a class named BothGreater that stores two int values set by the constructor. Neither should be publicly visible. BothGreater should also implement the Java Comparable<BothGreater> interface, returning 1 for a positive result and -1 for a negative result. An instance of BothGreater is greater than a second instance if both int values are larger, and is lesser than if both int values are smaller. Otherwise compareTo should return 0. The instance passed to compareTo will not be null.

You will probably need to review the documentation for Comparable. Because we are using the type parameter BothGreater to the Comparable interface, compareTo accepts an BothGreater as an argument.

Homework: Closer To A Pole

Created By: Geoffrey Challen

/ Version: 2022.10.0

Create a public class named Position. Position should define a single public constructor that accepts two fields: a latitude and longitude value, as double values, in that order. Your constructor should reject invalid latitude and longitude values. Valid longitude values are between -180.0 and 180.0, inclusive, while valid latitude values are between -90.0 and 90.0, inclusive.

Position should also implement the Java Comparable<Position> interface, returning 1 for a positive result and -1 for a negative result. An instance of Position is greater than a second instance if it is closer to either the North or South Pole, is lesser than the second instance if it is farther from the North or South Pole, and equal if it is at the same distance. The instance passed to compareTo will not be null.

You will probably need to review the documentation for Comparable. Because we are using the type parameter Position to the Comparable interface, compareTo accepts an Position as an argument.