JarCastingnashorn-maven-plugin
Purpose
nashorn-maven-plugin allows execute little piece of Javascript code during build. It is lightweight alternative to implement regular plugin
Example
Let say you want touch file 'x' during build. Classic Ant way:
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-antrun-plugin</artifactId>
<version>1.6</version>
<executions>
<execution>
<phase>process-resources</phase>
<configuration>
<target>
<touch file="${basedir}/x" />
</target>
</configuration>
<goals><goal>run</goal></goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
Nashorn way:
<build>
<plugins>
<plugin>
<groupId>io.github.michaldo</groupId>
<artifactId>nashorn-maven-plugin</artifactId>
<version>0.0.2</version>
<executions>
<execution>
<phase>process-resources</phase>
<goals><goal>eval</goal></goals>
<configuration>
<script>
var path = java.nio.file.Paths.get($basedir, 'x');
var Files = Java.type('java.nio.file.Files');
if (!Files.exists(path)) {
Files.createFile(path);
} else {
var FileTime = Java.type('java.nio.file.attribute.FileTime');
Files.setLastModifiedTime(path, FileTime.from(java.time.Instant.now()))
}
</script>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
No benefit of Nashorn way. But let say you have multi-module project with many jar and war module and you want to touch 'x' only for war module. For Ant it's impossible, huh? For Nashorn it is pretty easy
<build>
<plugins>
<plugin>
<groupId>io.github.michaldo</groupId>
<artifactId>nashorn-maven-plugin</artifactId>
<version>0.0.2</version>
<executions>
<execution>
<phase>process-resources</phase>
<goals><goal>eval</goal></goals>
<configuration>
<script>
if ($project.packaging != 'war') return;
var path = java.nio.file.Paths.get($basedir, 'x');
var Files = Java.type('java.nio.file.Files');
if (!Files.exists(path)) {
Files.createFile(path);
} else {
var FileTime = Java.type('java.nio.file.attribute.FileTime');
Files.setLastModifiedTime(path, FileTime.from(java.time.Instant.now()))
}
</script>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
Usage
<plugin>
<groupId>io.github.michaldo</groupId>
<artifactId>nashorn-maven-plugin</artifactId>
<version>0.0.2</version>
<executions>
<execution>
<phase>initialize</phase>
<goals><goal>eval</goal></goals>
<configuration>
<script>
print('hello world');
</script>
</configuration>
</execution>
</executions>
</plugin>
Goals
nashorn:eval: executes javascript code
Parameters
script : required script code
Maven API
The following Maven objects are injected in Javascript space
| Variable | Class |
|---|---|
| $project | actual MavenProject |
| $session | MavenSession |
| $mojo | MojoExecution |
| $plugin | MojoExecution.getMojoDescriptor().getPluginDescriptor() |
| $settings | MavenSession.getSettings() |
| $localRepository | MavenSession.getLocalRepository()() |
| $reactorProjects | MavenSession.getProjects() |
| $repositorySystemSession | MavenSession.getRepositorySession() |
| $executedProject | MavenProject.getExecutionProject() |
| $basedir | MavenProject.getBasedir() |
Requirements
Maven 3.1
Java 8