55 lines
1.8 KiB
Markdown
55 lines
1.8 KiB
Markdown
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JavaPoet Extensions for KotlinPoet
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==================================
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`interop:javapoet` is an interop API for converting [JavaPoet](https://github.com/squareup/javapoet)
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types to KotlinPoet types. This is particularly useful for projects that support code gen in
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multiple languages and want to easily be able to jump between.
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Note that this API is currently in preview and subject to API changes. Usage of them requires opting
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in to the `@KotlinPoetJavaPoetPreview` annotation.
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### Examples
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**Typealiases for common conflicting type names**
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```kotlin
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// Points to com.squareup.kotlinpoet.TypeName
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KTypeName
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// Points to com.squareup.javapoet.TypeName
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JTypeName
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```
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**Convert between a `JTypeName` and `KTypeName`**
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Most usages of these can run through the `toKTypeName()` and `toJTypeName()` extensions.
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```kotlin
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val jType = JTypeName.get("com.example", "Taco")
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// Returns a KotlinPoet `ClassName` of value `com.example.Taco`
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val kType = jType.toKTypeName()
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// Returns a JavaPoet `ClassName` of value `com.example.Taco`
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val jType2 = kType.toJTypeName()
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```
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### Intrinsics
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Kotlin supports a number of intrinsic types that live in the `kotlin` package, such as primitives,
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`List`, `String`, `IntArray`, etc. Where possible, interop will best-effort attempt to convert to
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the idiomatic Kotlin type when converting from the Java type.
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### Lossy Conversions
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Kotlin has more expressive types in some regards. These cannot be simply expressed in JavaPoet and
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are subject to lossy conversions.
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Examples include:
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- Nullability
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- Nullable types in Kotlin will appear as normal types in JavaPoet.
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- Collection mutability
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- Immutable Kotlin collections will convert to their standard (mutable) Java analogs.
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- Java collections will convert to _immutable_ Kotlin analogs, erring on the side of safety in generated public APIs
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- Unsigned types
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