Marco Pennekamp
35856ab58f
- This cache implementation is useful for lifecycle management of cached
values when we also want to allow the GC to reclaim those values which
are unused. It ensures that the cleanup is (almost) definitely invoked
at some point after a value has been reclaimed by the GC, and also
invokes the same cleanup operation when the value is removed from the
cache conventionally. This unifies the approach to cleaning up such
elements.
- It would be possible to have the cache ONLY perform cleanup for
references reclaimed by the GC, but this would put the onus on the
consumer to perform the cleanup when an element is removed from the
cache conventionally. That comes with its own pitfalls, such as
requiring the user to handle `clear` correctly, or not forgetting
to perform cleanup with the old value returned by `put`.
- "Almost definitely" because the reference queue won't be processed if
the cache becomes unused at some point. However, this is not an issue
for the current intended use case (session invalidation and disposal)
and can be solved by clearing the cache before it becomes entirely
unused.
- The cache requires read and write actions for certain operations to
simplify the implementation of `clear`.
^KT-61222
Kotlin Programming Language
Welcome to Kotlin!
It is an open-source, statically typed programming language supported and developed by JetBrains and open-source contributors.
Some handy links:
- Kotlin Site
- Getting Started Guide
- Try Kotlin
- Kotlin Standard Library
- Issue Tracker
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- Kotlin Blog
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- Public Slack channel
- TeamCity CI build
Kotlin Multiplatform capabilities
Support for multiplatform programming is one of Kotlin’s key benefits. It reduces time spent writing and maintaining the same code for different platforms while retaining the flexibility and benefits of native programming.
- Kotlin Multiplatform Mobile for sharing code between Android and iOS
- Getting Started with Kotlin Multiplatform Mobile Guide
- Kotlin Multiplatform Benefits
- Share code on all platforms
- Share code on similar platforms
Editing Kotlin
Build environment requirements
This repository is using Gradle toolchains feature to select and auto-provision required JDKs from AdoptOpenJdk project.
Unfortunately AdoptOpenJdk project does not provide required JDK 1.6 and 1.7 images,
so you could either download them manually and provide path to installation via JDK_1_6 and JDK_1_7 environment variables or
use following SDK managers:
Alternatively, it is still possible to only provide required JDKs via environment variables
(see gradle.properties for supported variable names). To ensure Gradle uses only JDKs
from environmental variables - disable Gradle toolchain auto-detection by passing -Porg.gradle.java.installations.auto-detect=false option
(or put it into $GRADLE_USER_HOME/gradle.properties).
For local development, if you're not working on the standard library, it's OK to avoid installing JDK 1.6 and JDK 1.7.
Add kotlin.build.isObsoleteJdkOverrideEnabled=true to the local.properties file, so build will only use JDK 1.8+. Note, that in this
case, build will have Gradle remote build cache misses for some tasks.
Note: The JDK 6 for MacOS is not available on Oracle's site. You can install it by
$ brew tap homebrew/cask-versions
$ brew install --cask java6
On Windows you might need to add long paths setting to the repo:
git config core.longpaths true
Building
The project is built with Gradle. Run Gradle to build the project and to run the tests using the following command on Unix/macOS:
./gradlew <tasks-and-options>
or the following command on Windows:
gradlew <tasks-and-options>
On the first project configuration gradle will download and setup the dependencies on
intellij-coreis a part of command line compiler and contains only necessary APIs.idea-fullis a full blown IntelliJ IDEA Community Edition to be used in the plugin module.
These dependencies are quite large, so depending on the quality of your internet connection you might face timeouts getting them. In this case, you can increase timeout by specifying the following command line parameters on the first run:
./gradlew -Dhttp.socketTimeout=60000 -Dhttp.connectionTimeout=60000
Important gradle tasks
clean- clean build resultsdist- assembles the compiler distribution intodist/kotlinc/folderinstall- build and install all public artifacts into local maven repositorycoreLibsTest- build and run stdlib, reflect and kotlin-test testsgradlePluginTest- build and run gradle plugin testscompilerTest- build and run all compiler tests
To reproduce TeamCity build use -Pteamcity=true flag. Local builds don't run proguard and have jar compression disabled by default.
OPTIONAL: Some artifacts, mainly Maven plugin ones, are built separately with Maven. Refer to libraries/ReadMe.md for details.
To build Kotlin/Native, see kotlin-native/README.md.
Working with the project in IntelliJ IDEA
It is recommended to use the latest released version of Intellij IDEA (Community or Ultimate Edition). You can download IntelliJ IDEA here.
After cloning the project, import the project in IntelliJ by choosing the project directory in the Open project dialog.
For handy work with compiler tests it's recommended to use Kotlin Compiler Test Helper
Dependency verification
We have a dependencies verification feature enabled in the
repository for all Gradle builds. Gradle will check hashes (md5 and sha256) of used dependencies and will fail builds with
Dependency verification failed errors when local artifacts are absent or have different hashes listed in the
verification-metadata.xml file.
It's expected that verification-metadata.xml should only be updated with the commits that modify the build. There are some tips how
to perform such updates:
- Delete
componentssection ofverification-metadata.xmlto avoid stockpiling of old unused dependencies. You may use the following command:
#macOS
sed -i '' -e '/<components>/,/<\/components>/d' gradle/verification-metadata.xml
#Linux & Git for Windows
sed -i -e '/<components>/,/<\/components>/d' gradle/verification-metadata.xml
- Re-generate dependencies with Gradle's
--write-verification-metadatacommand (verify update relates to your changes)
./gradlew -i --write-verification-metadata sha256,md5 -Pkotlin.native.enabled=true resolveDependencies
resolveDependencies task resolves dependencies for all platforms including dependencies downloaded by plugins.
Keep in mind:
- If you’re adding a dependency with OS mentioned in an artifact name (
darwin,mac,osx,linux,windows), remember to add them toimplicitDependenciesconfiguration or updateresolveDependenciestask if needed.resolveDependenciesshould resolve all dependencies including dependencies for different platforms. - If you have a
local.propertiesfile in your Kotlin project folder, make sure that it doesn't containkotlin.native.enabled=false. Otherwise, native-only dependencies may not be added to the verification metadata. This is becauselocal.propertieshas higher precedence than the-Pkotlin.native.enabled=truespecified in the Gradle command.
Using -dev versions
We publish -dev versions frequently.
For -dev versions you can use the list of available versions and include this maven repository:
maven("https://maven.pkg.jetbrains.space/kotlin/p/kotlin/bootstrap")
License
Kotlin is distributed under the terms of the Apache License (Version 2.0). See license folder for details.
Contributing
Please be sure to review Kotlin's contributing guidelines to learn how to help the project.