Hello.
I want to do a Gradle task on Java that will look for classes marked an annotation in my Java application and process those classes. This my task method:
@TaskAction
public void greet() throws {
Reflections reflections = new Reflections(“ru.mycomp”);
for (Class<?> clazz : reflections.getTypesAnnotatedWith(MisEntity2.class)) {
System.out.println(clazz.toString());
}
}
But the code find the clasess in Gradle project, not in my application.
Any ideas…
Thanks.
The classpath for tasks is defined by the buildscript { classpath { ... } }.
I’m guessing you’ll want to create a UrlClassLoader based on configurations.runtime.files and pass that to Reflections
Thank you very much Lance for your answer. Could you answer more in detail with example, because I am beginner.
@TaskAction
public void greet() {
Set<File> runtimeFiles = project.configurations.runtime.files
URL[] urls = runtimeFiles*.toUri().toUrl()
ClassLoader classLoader = new java.net.URLClassLoader(urls)
Configuration config = new ConfigurationBuilder("ru.mycomp", classLoader)
Reflections reflections = new Reflections(config)
for (Class<?> clazz : reflections.getTypesAnnotatedWith(MisEntity2.class)) {
...
}
}
Thanks a lot. Tomorrow I will try. When I have results, I will post them.
This is my function which I made from answer above:
private void scanAnnotatedFields2() throws MalformedURLException {
URL[] urls;
List<URL> listOfURL = new ArrayList<>();
for (Configuration configuration: getProject().getConfigurations() ){
System.out.println(configuration.getName());
}
System.out.println("---");
Set<File> runtimeFiles = getProject().getConfigurations().findByName("runtime").getFiles();
for(File file : runtimeFiles){
listOfURL.add(file.toURI().toURL());
System.out.println(file.getPath());
}
urls = listOfURL.toArray(new URL[0]);
ClassLoader classLoader = new java.net.URLClassLoader(urls);
Reflections reflections = new Reflections("ru.spsr", classLoader);
for (Class<?> clazz : reflections.getTypesAnnotatedWith(MisEntity3.class)) {
System.out.println(clazz.toString());
}
}
It don’t work. You advised “The classpath for tasks was defined by the buildscript { classpath { … } }.”. I have in this section reference on gradle plugin. Perhaps this is problem?
You’ll need to wire your task into Gradle’s DAG so that it runs after JavaCompile. Eg:
task myTask(type: MyReflectionsTask) {
dependsOn compileJava
...
}
You’ll obviously need reflections on the buildscript.depencies.classpath (I’m not sure if this task is from buildSrc or a plugin). You won’t need the scanned classes on the buildscript classpath because we are using UrlClassloader to avoid a chicken-or-egg scenario.
This is wiring:
public void apply(Project project) {
Task task = project.getTasks().create("mis", Task.class);
org.gradle.api.Task javaCompile = project.getTasks().getByName("compileJava");
org.gradle.api.Task build = project.getTasks().getByName("build");
//build.dependsOn(task);
task.dependsOn(javaCompile);
}
This is classpath:
buildscript {
repositories {
mavenLocal()
mavenCentral()
}
dependencies {
classpath 'ru.spsr:mis-template-plugin:1.0.0-SNAPSHOT'
classpath 'org.reflections:reflections:0.9.11'
}
}
It doesn’t work 
Application shows the classes of plugin project…
You might want to use the following so reflections doesn’t scan the buildscript classloader
new UrlClassloader(urls, null)
You can check that the classloader is configured properly by attempting:
classLoader.loadClass("foo.bar.MyClass")
If that’s able to load one of the classes you are scanning for, I think you’re best to head over to the reflections forum as this is no longer a gradle question
java.lang.ClassNotFoundException: ru.spsr.Request - The class is that I am scanning for in my application.
Perhaps I’ve misunderstood configurations.runtime. Please add this before creating the URL array
listOfURL.add(project.sourceSets.main.output.classesDir.toUri().toUrl())
In java code this is a little different than groovy. I think you’ll need to do
SourceSetContainer ssc = getProject().getConvention().getPlugin(JavaPluginConvention.class).getSourceSets();
File classesDir = ssc.getByName("main").getOutput().getClassesDir();
listOfURL.add(classesDir.toUri().toUrl());
Yes!!!
It works perfectly.
How can I thank you?
Hi I am new to gradle.
I intend to use reflection as part of the gradle task to read all the classes in one of the packages in my multi-module repo. Need some help as I end up getting the following error:
Execution failed for task ‘:hello’.
No signature of method: java.io.File.toUri() is applicable for argument types: () values:
Possible solutions: toURI(), toURL(), mkdir(), toString(), toPath(), toString()
######### Task Snippet
class AutogenTask extends DefaultTask {
@TaskAction
def greet() {
URL[] urls;
List<URL> listOfURL = new ArrayList<>();
SourceSetContainer ssc = getProject().getConvention().getPlugin(JavaPluginConvention.class).getSourceSets();
File classesDir = ssc.getByName("dir_name").getOutput().getClassesDir();
listOfURL.add(classesDir.toUri().toUrl());
urls = listOfURL.toArray(new URL[0]);
ClassLoader classLoader = new java.net.URLClassLoader(urls,null);
Reflections reflections = new Reflections("com.autogen.sample.common", classLoader);
Set<Class<? extends Object>> allClasses =
reflections.getSubTypesOf(Object.class)
println "I am here2"
for(Class c:allClasses) {
println "I am here3"
println "Derived Class : " + c.getName()
}
}
}
task hello(type: AutogenTask)
Have you read the error message? It’s being pretty specific
Change:
classesDir.toUri()
To
classesDir.toURI()
This is not throwing errors but it is also not getting the class names as it is intended here…
All the .java classes are under : com.autogenerate.data.common
class AutogenTask extends DefaultTask {
@TaskAction
def greet() {
List listOfURL = new ArrayList<>();
File classesDir = project.file(“auto/src/generatedData/java/com/autogenerate/data/common”)
listOfURL.add(classesDir.toURI().toURL());
URL[] urls = listOfURL.toArray(new URL[0]);
ClassLoader classLoader = new URLClassLoader(urls);
Reflections reflections = new Reflections("com.autogenerate.data.common", classLoader);
Set<Class<? extends Object>> allClasses =
reflections.getSubTypesOf(Object.class)
println "I am here2"
for(Class c:allClasses) {
println "I am here3"
println "Derived Class : " + c.getName()
}
}
}
Even if I go the route of SourceSetGenerator, I am still not able to grab the classes, where the package is in : auto ->java->com.autogenerate.data.common
class AutogenTask extends DefaultTask {
@TaskAction
def greet() {
SourceSetContainer ssc = getProject().findProject(“urns”).getConvention().getPlugin(JavaPluginConvention.class).getSourceSets();
File dir = ssc.getByName(“auto”).getOutput().getClassesDir();
List listOfURL = new ArrayList<>();
listOfURL.add(dir.toURI().toURL());
URL[] urls = listOfURL.toArray(new URL[0]);
ClassLoader classLoader = new URLClassLoader(urls);
Reflections reflections = new Reflections("com.autogenerate.data.common", classLoader);
Set<Class<? extends Object>> allClasses =
reflections.getSubTypesOf(Object.class)
for(Class c:allClasses) {
println "Class Name : " + c.getName()
}
}
}
task auto(type: AutogenTask)
Hi every body,
here is the way I get URLs:
final URL[] urls = project.sourceSets.main.output.classesDirs.files.collect { File dir ->
dir.listFiles()
}.flatten().collect {
getLogger().lifecycle(
"File?: " + it
)
if (it != null) {
it.toURI().toURL()
}
}.findAll {
it != null
} as URL[]
Notive that project.sourceSets.main.output.classesDir does not exist anymore.
Here is the Kotlin way I configure Reflections:
/**
* Secondary constructor with reflections configuration.
*
* @param packageName The name of the package to scan.
* @param configuration The [Configuration] to use.
*/
constructor(
packageName: String,
configuration: Configuration
) : this(
packageName = packageName,
reflections = Reflections(configuration)
)
/**
* Secondary constructor.
*
* @param packageName The name of the package to scan.
* @param classLoader The [ClassLoader] to use.
*/
constructor(
packageName: String,
classLoader: ClassLoader
) : this(
packageName = packageName,
configuration = ConfigurationBuilder(
).setUrls(
ClasspathHelper.forClassLoader(classLoader)
).setScanners(
SubTypesScanner(false),
TypeAnnotationsScanner()
).addClassLoader(
classLoader
)
)
/**
* Secondary constructor.
*
* @param packageName The name of the package to scan.
* @param urls The [URL] array to use.
*/
constructor(
packageName: String,
urls: Array<URL>
) : this(
packageName = packageName,
classLoader = URLClassLoader(urls)
)
The, when performing:
val list = reflections.getSubTypesOf(
Any::class.java
).asIterable().toList()
I get the following error:
Caused by: java.lang.ClassNotFoundException: com.github.roroche.eoplantumlbuilder.classes.ClsFiltered
The plugin code is here: https://github.com/RoRoche/plantuml-gradle-plugin
The project including it is here: https://github.com/RoRoche/eo-plantuml-builder
Any idea?
How to unit test it?
I don’t find unit testing Gradle plugins very helpful since it’s easy to get a false positive. So I usually only provide integration tests with TestKit. Since gradle scripts are groovy, you can put assert statements in your test gradle scripts which I find convenient.
Eg