Java – getters / setters of classes with maps

What are the best practices for implementing / providing getters / setters for courses with maps?

The most common implementations I see are:

public class MyClass {

  private Map<String,String> myMap;
  public getMyMap() { /* Return an unmodifiable map */ }
  public setMyMap(Map<String,String> myMap) { ... }
}

Or it is better to provide an interface, such as:

public getMyMap() { /* Return a modifiable map */ }
public addToMap(String key,String value) { myMap.put(key,value); }

Why is this method better?

Solution

Both have their uses The methods exposed by the class should have an appropriate level of abstraction For example, if this class is a dog registry supported by map < string, dog >, it can provide the following methods:

void addDog(String name,Dog dog);
Dog findByName(String name);

If it is a rule engine that allows the client to specify the entire rule set in one call, it can display the following methods:

void setRules(Map<String,Rule> rules);
Map<String,Rule> getRules();