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Summary

To summarize, if you want to fully integrate a new collection class into the framework you need to pay attention to the following points:
  1. Decide whether the collection should be mutable or immutable.
  2. Pick the right base traits for the collection.
  3. Inherit from the right implementation trait to implement most collection operations.
  4. If you want map and similar operations to return instances of your collection type, provide an implicit CanBuildFrom in your class's companion object.
 

You have now seen how Scala's collections are built and how you can build new kinds of collections. Because of Scala's rich support for abstraction, each new collection type can have a large number of methods without having to reimplement them all over again.

Acknowledgement

These pages contain material adapted from the 2nd edition of Programming in Scala by Odersky, Spoon and Venners. We thank Artima for graciously agreeing to its publication.

ContentsTopIntegrating new sets and mapsSummaryContents