# Custom Similiarity Plugin

**URL:** <https://discuss.elastic.co/t/custom-similiarity-plugin/148737>\
**Category:** Elasticsearch\
**Created:** [September 16, 2018, 8:29am UTC](https://discuss.elastic.co/t/custom-similiarity-plugin/148737 "2018-09-16T08:29:56Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![micmer](https://avatars.discourse-cdn.com/v4/letter/m/3e96dc/32.png) [@micmer](https://discuss.elastic.co/u/micmer)\
**Post date:** [September 16, 2018, 8:29am UTC](https://discuss.elastic.co/t/custom-similiarity-plugin/148737/1 "2018-09-16T08:29:56Z")

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Hi, I want to update my custom similarity plugin from version 6.2 to version 6.4. However the AbstractSimilarityProvider class has been removed from version 6.4. That class I was using so far for making my lucene Similarity class available in elasticsearch. What is the proper way of integrating a similarity plugin into version 6.4?

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<div class="post-metadata">

**Author:** ![rjernst](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/rjernst/32/6363_2.png) [@rjernst](https://discuss.elastic.co/u/rjernst)\
**Post date:** [September 17, 2018, 2:46am UTC](https://discuss.elastic.co/t/custom-similiarity-plugin/148737/2 "2018-09-17T02:46:54Z")

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You need to implement the onIndexModule of `Plugin`, and call `addSimilarity`. This takes a function which will construct your Similarity from Settings, Version and the ScriptService.

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<div class="post-metadata">

**Author:** ![micmer](https://avatars.discourse-cdn.com/v4/letter/m/3e96dc/32.png) [@micmer](https://discuss.elastic.co/u/micmer)\
**Post date:** [September 17, 2018, 6:54am UTC](https://discuss.elastic.co/t/custom-similiarity-plugin/148737/3 "2018-09-17T06:54:49Z")

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Thanks a lot. That worked out for me. In case it helps anyone, here is the code I ended up with:

```
public void onIndexModule(IndexModule indexModule) {
	super.onIndexModule(indexModule); //not sure if this is necessary
	indexModule.addSimilarity("myfancysimilarity",
			(settings, indexCreatedVersion, scriptService) -> new MyFancySimilarity());
	
}
```

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [October 15, 2018, 6:54am UTC](https://discuss.elastic.co/t/custom-similiarity-plugin/148737/4 "2018-10-15T06:54:50Z")

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