This is a Gradle plugin to allow easily performing Java code generation for Apache Avro. It supports JSON schema declaration files, JSON protocol declaration files, and Avro IDL files.
- Currently tested against Java 7-9
- Java 9 support requires Gradle 4.2.1 or higher
- If you need support for Java 6, version 0.9.1 was the last supported version
- Currently built against Gradle 4.5
- Currently tested against Gradle 3.0-3.51 and 4.0-4.5
- If you need support for Gradle 2.0-2.14.1, version 0.9.1 was the last version tested for compatibility
- Other versions may be compatible, but Gradle 1.x versions are unlikely to work
- Currently built against Avro 1.8.2
- Currently tested against Avro 1.8.2; other versions may be compatible
- If you need support for Avro 1.8.0-1.8.1, try plugin version 0.10.0
- If you need support for Avro 1.7.x, try plugin version 0.8.0; versions of Avro before that are unlikely to work
- Incubating: support for Kotlin
- Currently tested against Kotlin 1.1.51
- Kotlin 1.1.2 and higher requires Java 8+
- Doesn't work with Gradle 3.2-3.2.1
Add the following to your build.gradle file. Substitute the desired version based on CHANGES.md.
buildscript {
repositories {
jcenter()
}
dependencies {
classpath "com.commercehub.gradle.plugin:gradle-avro-plugin:VERSION"
}
}
apply plugin: "com.commercehub.gradle.plugin.avro"Additionally, ensure that you have a compile dependency on Avro, such as:
repositories {
jcenter()
}
dependencies {
compile "org.apache.avro:avro:1.8.2"
}If you now run gradle build, Java classes will be compiled from Avro files in src/main/avro.
Actually, it will attempt to process an "avro" directory in every SourceSet (main, test, etc.)
Alternatively, if you prefer to use the incubating plugins DSL, see the following example:
settings.gradle:
pluginManagement {
repositories {
gradlePluginPortal()
jcenter()
maven {
name "JCenter Gradle Plugins"
url "https://dl.bintray.com/gradle/gradle-plugins"
}
}
}build.gradle:
plugins {
id "com.commercehub.gradle.plugin.avro" version "VERSION"
}There are a number of configuration options supported in the avro block.
| option | default | description |
|---|---|---|
| createSetters | true |
createSetters passed to Avro compiler |
| fieldVisibility | "PUBLIC_DEPRECATED" |
fieldVisibility passed to Avro compiler |
| outputCharacterEncoding | see below | outputCharacterEncoding passed to Avro compiler |
| stringType | "String" |
stringType passed to Avro compiler |
| templateDirectory | see below | templateDir passed to Avro compiler |
| enableDecimalLogicalType | true |
enableDecimalLogicalType passed to Avro compiler |
| validateDefaults | false |
setValidateDefaults set on Avro Schema Parser |
Valid values: true (default), false; supports equivalent String values
Set to false to not create setter methods in the generated classes.
Example:
avro {
createSetters = false
}Valid values: any FieldVisibility or equivalent String name (matched case-insensitively); default "PUBLIC_DEPRECATED" (default)
By default, the fields in generated Java files will have public visibility and be annotated with @Deprecated.
Set to "PRIVATE" to restrict visibility of the fields, or "PUBLIC" to remove the @Deprecated annotations.
Example:
avro {
fieldVisibility = "PRIVATE"
}Valid values: any Charset or equivalent String name
Controls the character encoding of generated Java files.
If the associated JavaCompile task has a configured encoding, it will be used automatically.
Otherwise, it will use the value configured in the avro block, defaulting to "UTF-8".
Examples:
// Option 1: configure compilation task (avro plugin will automatically match)
tasks.withType(JavaCompile) {
options.encoding = 'UTF-8'
}
// Option 2: just configure avro plugin
avro {
outputCharacterEncoding = "UTF-8"
}Valid values: any StringType or equivalent String name (matched case-insensitively); default "String" (default)
By default, the generated Java files will use java.lang.String to represent string types.
Alternatively, you can set it to "Utf8" to use org.apache.avro.util.Utf8 or "charSequence" to use java.lang.CharSequence.
avro {
stringType = "CharSequence"
}By default, files will be generated using Avro's default templates.
If desired, you can override the template set used by either setting this property or the "org.apache.avro.specific.templates" System property.
avro {
templateDirectory = "/path/to/velocity/templates"
}Valid values: true (default), false; supports equivalent String values
By default, generated Java files will use java.math.BigDecimal
for representing fixed or bytes fields annotated with "logicalType": "decimal".
Set to false to use java.nio.ByteBuffer in generated classes.
Example:
avro {
enableDecimalLogicalType = false
}Valid values: false (default), true; supports equivalent String values
Set to true to force validation of default values in schema files. Each validation error will cause the build to fail.
In order to maintain backward compatibility this option is disabled by default, but in the next big release, this option will
be removed and schema validation will always be enabled.
Example:
avro {
validateDefaults = true
}The plugin attempts to make IntelliJ play more smoothly with generated sources when using Gradle-generated project files.
However, there are still some rough edges. It will work best if you first run gradle build, and after that run gradle idea.
If you do it in the other order, IntelliJ may not properly exclude some directories within your build directory.
If the defaults used by the plugin don't work for you, you can still use the tasks by themselves.
In this case, use the com.commercehub.gradle.plugin.avro-base plugin instead, and create tasks of type GenerateAvroJavaTask and/or GenerateAvroProtocolTask.
Here's a short example of what this might look like:
apply plugin: "java"
apply plugin: "com.commercehub.gradle.plugin.avro-base"
dependencies {
compile "org.apache.avro:avro:1.8.2"
}
task generateAvro(type: com.commercehub.gradle.plugin.avro.GenerateAvroJavaTask) {
source("src/avro")
outputDir = file("dest/avro")
}
compileJava.source(generateAvro.outputs)When using this plugin, it is recommended to define each record/enum/fixed type in its own file rather than using inline type definitions.
This approach allows defining any type of schema structure, and eliminates the potential for conflicting definitions of a type between multiple files.
The plugin will automatically recognize the dependency and compile the files in the correct order.
For example, instead of Cat.avsc:
{
"name": "Cat",
"namespace": "example",
"type": "record",
"fields" : [
{
"name": "breed",
"type": {
"name": "Breed",
"type": "enum",
"symbols" : [
"ABYSSINIAN", "AMERICAN_SHORTHAIR", "BIRMAN", "MAINE_COON", "ORIENTAL", "PERSIAN", "RAGDOLL", "SIAMESE", "SPHYNX"
]
}
}
]
}use Breed.avsc:
{
"name": "Breed",
"namespace": "example",
"type": "enum",
"symbols" : ["ABYSSINIAN", "AMERICAN_SHORTHAIR", "BIRMAN", "MAINE_COON", "ORIENTAL", "PERSIAN", "RAGDOLL", "SIAMESE", "SPHYNX"]
}and Cat.avsc:
{
"name": "Cat",
"namespace": "example",
"type": "record",
"fields" : [
{"name": "breed", "type": "Breed"}
]
}There may be cases where the schema files contain inline type definitions and it is undesirable to modify them. In this case, the plugin will automatically recognize any duplicate type definitions and check if they match. If any conflicts are identified, it will cause a build failure.
The Java classes generated from your Avro files should be automatically accessible in the classpath to Kotlin classes in the same sourceset, and transitively to any sourcesets that depend on that sourceset. This is accomplished by this plugin detecting that the Kotlin plugin has been applied, and informing the Kotlin compilation tasks of the presence of the generated sources directories for cross-compilation.
This support does not support producing the Avro generated classes as Kotlin classes, as that functionality is not currently provided by the upstream Avro library.