# DummyQueryParserPlugin doesn't compile out of package

**URL:** <https://discuss.elastic.co/t/dummyqueryparserplugin-doesnt-compile-out-of-package/70171>\
**Category:** Elasticsearch\
**Created:** [December 28, 2016, 11:42pm UTC](https://discuss.elastic.co/t/dummyqueryparserplugin-doesnt-compile-out-of-package/70171 "2016-12-28T23:42:57Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![softwaredoug](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/softwaredoug/32/22681_2.png) [@softwaredoug](https://discuss.elastic.co/u/softwaredoug)\
**Post date:** [December 28, 2016, 11:42pm UTC](https://discuss.elastic.co/t/dummyqueryparserplugin-doesnt-compile-out-of-package/70171/1 "2016-12-28T23:42:57Z")

</div>

I've been working on a custom query / custom query builder. As a starting point, I copy/pasted [DummyQueryBuilder and DummyQueryParserPlugin](https://github.com/elastic/elasticsearch/tree/master/core/src/test/java/org/elasticsearch/index/query/plugin) out of Elasticsearch's source and into my package. I've only changed the package.

Unfortunately, this code by itself, only changing the package doesn't compile. I get an error in DummyQueryParserPlugin on this line:

```
@Override
public List<QuerySpec<?>> getQueries() {
    return singletonList(new QuerySpec<>(DummyQueryBuilder.NAME, DummyQueryBuilder::new, DummyQueryBuilder::fromXContent));
}

```

> Error:(40, 34) java: cannot infer type arguments for org.elasticsearch.plugins.SearchPlugin.QuerySpec\<\>

I've seen this on Java 7 and 8. I'm using Elasticsearch 5.1.1

Should I expect this line to work outside of `package org.elasticsearch.index.query.plugin;`?

---

<div class="post-metadata">

**Author:** ![softwaredoug](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/softwaredoug/32/22681_2.png) [@softwaredoug](https://discuss.elastic.co/u/softwaredoug)\
**Post date:** [December 29, 2016, 12:22am UTC](https://discuss.elastic.co/t/dummyqueryparserplugin-doesnt-compile-out-of-package/70171/2 "2016-12-29T00:22:08Z")

</div>

I solved it, though I'm not entirely sure why it matters. The issue boils down to the fact that the QueryParser interface is a functional interface that experts fromXContent to return an `Optional<DummyQueryBuilder>`. By performing that conversion directly, I can get it to work. So this code works:

```auto
    @Override
    public List<QuerySpec<?>> getQueries() {
        QueryParser<DummyQueryBuilder> qp = new QueryParser<DummyQueryBuilder>() {
            @Override
            public Optional<DummyQueryBuilder> fromXContent(QueryParseContext parseContext) throws IOException {
                Optional<DummyQueryBuilder> opt;
                opt = Optional.of(DummyQueryBuilder.fromXContent(parseContext));
                return opt;

            }
        };
        return singletonList(new QuerySpec<>(DummyQueryBuilder.NAME, DummyQueryBuilder::new, qp));
    }

```

---

<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:** [January 26, 2017, 12:22am UTC](https://discuss.elastic.co/t/dummyqueryparserplugin-doesnt-compile-out-of-package/70171/3 "2017-01-26T00:22:12Z")

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