MultiMap implementation similar to Guava MultiMap implementations.

[fanifieiev]

The Takes framework code contains a lot of boilerplate when using, for instance, Map<String, Collection<String>>. Example of boilerplate:

final Map<String, List<String>> map = new HashMap<>();
 .....
 .....
 if (!map.containsKey(key)) {
     map.put(key, new LinkedList<>());
 }
 map.get(key).add(<some_string>)
 .......

Would be great to have something like:

final CollectionMap<String, String> map = new CollectionMapOf(
   "key1", "value1", "value2"
);
 ....
 map.put("key1", "value3");
 map.put("key2", "value4"); //without checking if the value collection exists

Note: Need to think about specific implementation of collection passed to CollectionMapOf or create dedicated implementations for each use case like:

• LinkedListMapOf
• ArrayListMapOf
• HashSetMapOf
• TreeSetMapOf etc @paulodamaso, @yegor256, @fabriciofx, @victornoel, @iakunin What do you think about it?

[0crat]

@paulodamaso/z please, pay attention to this issue

[victornoel]

@fanifieiev @paulodamaso I've already raised this question in the past: do we target with cactoos a lib with mostly OO decorators (such as those on Iterable and Iterator that are really great and unique in the Java world I think), or do we want cactoos to become a fully fledged collection implementation library?

The latest is a huge endeavour, and I wonder what anybody would gain from it: while the decorators provides something that does not already exists, there are many libraries implementing collections and they as OO as possible (because the java collection api is not great).

[fanifieiev]

@fanifieiev @paulodamaso I've already raised this question in the past: do we target with cactoos a lib with mostly OO decorators (such as those on Iterable and Iterator that are really great and unique in the Java world I think), or do we want cactoos to become a fully fledged collection implementation library?

The latest is a huge endeavour, and I wonder what anybody would gain from it: while the decorators provides something that does not already exists, there are many libraries implementing collections and they as OO as possible (because the java collection api is not great).

@victornoel In the description of Cactoos project it is stated that the target of the project is: Object-Oriented Java primitives, as an alternative to Google Guava and Apache Commons, so why should this feature not be there then?

[victornoel]

@fanifieiev so in the end, this is out of scope of cactoos for now until v1 is released, and then we can take into the scope