fix(GH-233): Support Inline optional search criteria for singular and plural attributes

[igdianov]

This PR contains the following changes:

• Support for Inline optional singular attributes (Fixes Inline optional with where is not optional #233), i.e. query

query {
  Humans {
    select {
      id
      name
      favoriteDroid(optional:true, where:{name:{LIKE:"R2"}}) {
        name
      }
    }
  }
}

will result in

{
  "data": {
    "Humans": {
      "select": [
        {
          "id": "1000",
          "name": "Luke Skywalker",
          "favoriteDroid": null
        },
        {
          "id": "1001",
          "name": "Darth Vader",
          "favoriteDroid": {
            "name": "R2-D2"
          }
        },
        {
          "id": "1002",
          "name": "Han Solo",
          "favoriteDroid": null
        },
        {
          "id": "1003",
          "name": "Leia Organa",
          "favoriteDroid": null
        },
        {
          "id": "1004",
          "name": "Wilhuff Tarkin",
          "favoriteDroid": null
        }
      ]
    }
  }
}

• Support for inline filtering of plural attributes, i.e. query

  Authors {
    select {
      id
      name
      books(where: {title: {LIKE: "War"}}) {
        title
      }
    }
  }

will return filtered books for each author

{
  "data": {
    "Authors": {
      "select": [
        {
          "id": 1,
          "name": "Leo Tolstoy",
          "books": [
            {
              "title": "War and Peace"
            }
          ]
        },
        {
          "id": 4,
          "name": "Anton Chekhov",
          "books": []
        },
        {
          "id": 8,
          "name": "Igor Dianov",
          "books": []
        }
      ]
    }
  }
}

• Support of inline sorting of plural attribute selections i.e. the query

  Authors {
    select {
      id
      name(orderBy: ASC)
      books {
        id
        title(orderBy: DESC)
      }
    }
  }

will sort authors by name in ASC order with books title in DESC order:

{
  "data": {
    "Authors": {
      "select": [
        {
          "id": 4,
          "name": "Anton Chekhov",
          "books": [
            {
              "id": 7,
              "title": "Three Sisters"
            },
            {
              "id": 6,
              "title": "The Seagull"
            },
            {
              "id": 5,
              "title": "The Cherry Orchard"
            }
          ]
        },
        {
          "id": 8,
          "name": "Igor Dianov",
          "books": []
        },
        {
          "id": 1,
          "name": "Leo Tolstoy",
          "books": [
            {
              "id": 2,
              "title": "War and Peace"
            },
            {
              "id": 3,
              "title": "Anna Karenina"
            }
          ]
        }
      ]
    }
  }
}

• Support for aliases, i.e.

{
  Authors {
    select {
      id
      name
      War: books(where: {title: {LIKE: "War"}}) {
        title
      }
      Anna: books(where: {title: {LIKE: "Anna"}}) {
        title
      }
    }
  }
}

will return the following result:

{
  "data": {
    "Authors": {
      "select": [
        {
          "id": 1,
          "name": "Leo Tolstoy",
          "War": [
            {
              "title": "War and Peace"
            }
          ],
          "Anna": [
            {
              "title": "Anna Karenina"
            }
          ]
        },
        {
          "id": 4,
          "name": "Anton Chekhov",
          "War": [],
          "Anna": []
        },
        {
          "id": 8,
          "name": "Igor Dianov",
          "War": [],
          "Anna": []
        }
      ]
    }
  }
}

In order to support inline search criteria with optional association, the framework is now using GraphQL Java Dataloader in order to optimize query perfromance.

[codecov]

Codecov Report

Merging #251 into master will increase coverage by 1.47%.
The diff coverage is 89.20%.

@@             Coverage Diff              @@
##             master     #251      +/-   ##
============================================
+ Coverage     70.86%   72.33%   +1.47%     
- Complexity      957     1025      +68     
============================================
  Files            66       71       +5     
  Lines          4434     4674     +240     
  Branches        661      674      +13     
============================================
+ Hits           3142     3381     +239     
+ Misses         1013     1005       -8     
- Partials        279      288       +9     

Impacted Files	Coverage Δ	Complexity Δ
.../query/schema/impl/GraphQLJpaToOneDataFetcher.java	70.37% <70.37%> (ø)	5.00 <5.00> (?)
...ures/graphql/jpa/query/support/GraphQLSupport.java	80.59% <70.58%> (+4.59%)	28.00 <6.00> (+8.00)
.../schema/impl/GraphQLJpaExecutorContextFactory.java	76.31% <76.92%> (+0.31%)	12.00 <4.00> (+4.00)
.../jpa/query/schema/impl/GraphQLJpaQueryFactory.java	78.40% <86.40%> (+2.66%)	219.00 <29.00> (+24.00)
...a/query/schema/impl/GraphQLJpaExecutorContext.java	97.82% <95.45%> (-2.18%)	10.00 <5.00> (+3.00)	⬇️
...hql/jpa/query/schema/impl/BatchLoaderRegistry.java	100.00% <100.00%> (ø)	8.00 <8.00> (?)
...jpa/query/schema/impl/GraphQLJpaSchemaBuilder.java	89.09% <100.00%> (+0.47%)	127.00 <1.00> (+1.00)
...query/schema/impl/GraphQLJpaToManyDataFetcher.java	100.00% <100.00%> (ø)	6.00 <6.00> (?)
...schema/impl/GraphQLJpaToManyMappedBatchLoader.java	100.00% <100.00%> (ø)	3.00 <3.00> (?)
.../schema/impl/GraphQLJpaToOneMappedBatchLoader.java	100.00% <100.00%> (ø)	3.00 <3.00> (?)
... and 8 more

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