How Do You Implement a Map with Multiple Keys of Different Types?

Multiple Keys in a Custom Map Structure

In the realm of data structures, the Map interface serves as a valuable tool for managing key-value pairs. However, what happens when you encounter the need for a map with multiple keys, each of a different type?

This question arises when you require a data structure that allows you to retrieve and store data using multiple unique keys. Unlike Java's native Map, which only accepts a single key, this customized implementation aims to accommodate two differently-typed keys.

Possible Solution: Multiple Maps

One approach to implementing a map with multiple keys is to utilize two separate maps internally. One map, Map, would map keys of type K1 to values, while the other map, Map, would map keys of type K2 to the same values.

This solution offers flexibility by allowing you to access values using either K1 or K2 keys through the following methods:

• getByKey1(K1 key): Retrieves the value associated with the given K1 key.
• getByKey2(K2 key): Retrieves the value associated with the given K2 key.
• containsKey1(K1 key): Checks if the map contains the given K1 key.
• containsKey2(K2 key): Checks if the map contains the given K2 key.

Wrapper Class Approach

If you desire a more cohesive interface, you can consider wrapping the two internal maps within a class. This wrapper class would expose methods like getByKey1, getByKey2, containsKey1, and containsKey2, providing a seamless user experience while retaining the functionality of the multiple maps.

In essence, this approach enables you to create a custom Map structure that supports the use of multiple keys for accessing and storing data. It offers a convenient solution for situations where a standard single-key Map is insufficient.

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