gradle/testing/alternative-jdk-support.gradle

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// This adds support for compiling and testing against a different Java runtime.
// This is the only way to build against JVMs not yet supported by Gradle itself.

JavaInstallationRegistry registry = extensions.getByType(JavaInstallationRegistry)

JavaInstallation currentJvm = registry.installationForCurrentVirtualMachine.get()

JavaInstallation altJvm = {
  def runtimeJavaHome = propertyOrDefault("runtime.java.home", System.getenv('RUNTIME_JAVA_HOME'))
  if (!runtimeJavaHome) {
    return currentJvm
  } else {
    return registry.installationForDirectory(
        layout.projectDirectory.dir(runtimeJavaHome)).get()
  }
}()

// Set up root project's property.
rootProject.ext.runtimeJava = altJvm
rootProject.ext.runtimeJavaVersion = altJvm.javaVersion

if (!currentJvm.javaExecutable.equals(altJvm.javaExecutable)) {
  // Set up java toolchain tasks to use the alternative Java.
  // This is a related Gradle issue for the future:
  // https://github.com/gradle/gradle/issues/1652

  configure(rootProject) {
    task altJvmWarning() {
      doFirst {
        logger.warn("""NOTE: Alternative java toolchain will be used for compilation and tests:
  Project will use Java ${altJvm.javaVersion} from: ${altJvm.installationDirectory}
  Gradle runs with Java ${currentJvm.javaVersion} from: ${currentJvm.installationDirectory}
""")
      }
    }
  }

  // Set up toolchain-dependent tasks to use the alternative JVM.
  allprojects {
    // Any tests
    tasks.withType(Test) {
      dependsOn ":altJvmWarning"
      executable = altJvm.javaExecutable
    }

    // Any javac compilation tasks
    tasks.withType(JavaCompile) {
      dependsOn ":altJvmWarning"
      options.fork = true
      options.forkOptions.javaHome = altJvm.installationDirectory.asFile
    }

    // Javadoc compilation.
    def javadocExecutable = altJvm.jdk.get().javadocExecutable.asFile
    tasks.matching { it.name == "renderJavadoc" || it.name == "renderSiteJavadoc" }.all {
      dependsOn ":altJvmWarning"
      executable = javadocExecutable
    }
  }
}