Kotlin JSON Builder

A Kotlin typesafe builder for Jackson JsonNodes

License	BSD License
Categories	Kotlin Languages JSON Data
GroupId	codes.matteo
ArtifactId	kotlin-json-builder
Last Version	1.0
Release Date	Feb 21, 2018
Type	jar
Description	Kotlin JSON Builder A Kotlin typesafe builder for Jackson JsonNodes
Project URL	https://github.com/matteobanerjee/kotlin-json-builder
Source Code Management	https://github.com/matteobanerjee/kotlin-json-builder

Download kotlin-json-builder

Filename	Size
kotlin-json-builder-1.0.pom
kotlin-json-builder-1.0.jar	6 KB
kotlin-json-builder-1.0-sources.jar	1 KB
kotlin-json-builder-1.0-javadoc.jar	261 bytes

How to add to project

Apache Maven

<!-- https://jarcasting.com/artifacts/codes.matteo/kotlin-json-builder/ -->
<dependency>
    <groupId>codes.matteo</groupId>
    <artifactId>kotlin-json-builder</artifactId>
    <version>1.0</version>
</dependency>

Gradle Groovy

// https://jarcasting.com/artifacts/codes.matteo/kotlin-json-builder/
implementation 'codes.matteo:kotlin-json-builder:1.0'

Gradle Kotlin

// https://jarcasting.com/artifacts/codes.matteo/kotlin-json-builder/
implementation ("codes.matteo:kotlin-json-builder:1.0")

Apache Buildr

'codes.matteo:kotlin-json-builder:jar:1.0'

Apache Ivy

<dependency org="codes.matteo" name="kotlin-json-builder" rev="1.0">
  <artifact name="kotlin-json-builder" type="jar" />
</dependency>

Groovy Grape

@Grapes(
@Grab(group='codes.matteo', module='kotlin-json-builder', version='1.0')
)

Scala SBT

libraryDependencies += "codes.matteo" % "kotlin-json-builder" % "1.0"

Leiningen

[codes.matteo/kotlin-json-builder "1.0"]

Dependencies

compile (4)

Group / Artifact	Type	Version
org.jetbrains.kotlin : kotlin-stdlib-jdk8	jar	1.2.21
org.jetbrains.kotlin : kotlin-reflect	jar	1.2.21
com.fasterxml.jackson.core : jackson-core	jar	2.9.4
com.fasterxml.jackson.core : jackson-databind	jar	2.9.4

test (1)

Group / Artifact	Type	Version
junit : junit	jar	4.12

Project Modules

There are no modules declared in this project.

kotlin-json-builder

A reasonably fast, reasonably elegant Kotlin typesafe builder for Jackson JSON objects.

Usage

The DSL provides two functions: jsObject and jsArray. In addition to jsObject and jsArray, basic Kotlin types are supported: Boolean, String, Int, Long and Kotlin Arrays of those types. The DSL errs on the side of typesafety and doesn't allow potentially un-serializable objects to be created. Using Array is preferable over jsArray unless you need deeply nested arrays or mixed type arrays.

• jsObject provides the /= operator to associate string keys to values
• jsArray provides the elem method to add elements.

That's it! Here is an example:

val obj = jsObject {
        // nested object
        "data" /= jsObject {
            "id" /= 1
            "name" /= "Joe"
            // native array
            "tags" /= arrayOf("a", "b")
            // jsArray
            "nested_array" /= jsArray { elem(jsArray { elem(1) }) }
        }
      }
 
val arr = jsArray {
  elem(1)
  elem("something")
  elem(obj)
} 

// call `asTree()` to get the JsonNode representation
// a trivial jackson module could be added in the future to us to skip this
val serialized = ObjectMapper().writeValueAsString(obj.asTree())

Benchmarks

This project includes basic JMH benchmarks for serialization. These compare using the DSL to data class databinding and various methods of constructing dynamic JSON objects. The aim is to ensure that DSL performance stays in the same ballpark as databinding and hand-written Jackson ObjectNode code.

To run benchmarks:

./gradlew clean jmh

# if you get errors, you might need to remove the gradle cache:
# rm -r ~/.gradle

Latest results

Benchmark                    Mode  Cnt        Score       Error  Units
BenchKotlin.dataClass       thrpt   20  2532032.245 ± 34718.349  ops/s
BenchKotlin.dsl             thrpt   20  1514419.037 ± 26120.672  ops/s
BenchKotlin.handWritten     thrpt   20  1560949.008 ± 12864.029  ops/s
BenchKotlin.mapOf           thrpt   20  1413689.265 ± 10756.033  ops/s
BenchKotlin.stringInterpol  thrpt   20   106053.933 ±   499.961  ops/s

Versions

Version
1.0 Feb 21, 2018