Creating RepositorySystemSession using Aether - maven

I'm trying to get all transitive dependencies of a maven project in a List of Artifacts.
I found the documentation of Aether with some example code to set up the process. One part of it is the RepositorySystem.
private static RepositorySystem newRepositorySystem() {
DefaultServiceLocator locator = MavenRepositorySystemUtils.newServiceLocator();
locator.addService(RepositoryConnectorFactory.class, BasicRepositoryConnectorFactory.class);
locator.addService(TransporterFactory.class, FileTransporterFactory.class);
locator.addService(TransporterFactory.class, HttpTransporterFactory.class);
return locator.getService(RepositorySystem.class);
}
But I get a NullPointerException in the return value.
I have no idea why?
Big thanks

Related

How can I fix Unresolved reference: Gson?

I'm trying to follow a tutorial about Android application. I'm using an dependency Fuel (which has a dependency to com.google.Gson deserializer). But Gson() is not imported by IDE.
I've tried to specify lower version of gson. I've re-synchronized all project gradle. I've tried to write import manually (import com.google.gson.Gson), but I can't use Gson() constructor. I've read manual about using Gson, but nothing seem to be changed. It's always the same way. Call constructor Gson() and after all static method... Gson().fromJson(....)
Here is section in my build.gradle (module:app)
// Fuel HTTP Client
implementation 'com.github.kittinunf.fuel:fuel:2.2.0'
implementation 'com.github.kittinunf.fuel:fuel-android:2.2.0'
implementation 'com.github.kittinunf.fuel:fuel-gson:2.2.0'
and In code, I'm using in ArticleDataProvider.kt:
class WikipediaDataDeserializer : ResponseDeserializable<WikiResults> {
override fun deserialize(reader: Reader): WikiResults? {
return Gson().fromJson(reader, WikiResults::class.java)
}
}
Normally, I would to have Gson() recognised by IDE and I wound be able to call .fromJson() normally. Gradle was downloaded properly. (I don't have any message error about).
Using this Lib in your gradle:
dependencies{
implementation 'com.google.code.gson:gson:2.8.2'
}
The problem is probably in dependency of fuel-gson:2.2.0
To bypass it, I added a new dependency to my build.gradle manually and problem is solved.
dependencies {
implementation 'com.google.code.gson:gson:2.8.5'
}
Its may happen due to different versions of gson in External Libraries. To resolve it I have added following resolveStrategy in app module build.gradle.
configurations.all {
resolutionStrategy.preferProjectModules()
resolutionStrategy.eachDependency { DependencyResolveDetails details ->
def requested = details.requested
if (requested.group == 'com.google.code.gson') {
details.useVersion "2.8.5"
}
}
}

How to declare project artifacts in non-Java build?

I have multi-project Gradle build that contains also non-Java projects.
I want to declare the artifacts create by one such project in a way that I can use project/configuration dependencies to get them, e.g.
consumer:
dependencies {
myConf project(path: ':producer', configuration: 'myConf')
}
What I currently have is this:
producer:
configurations {
myConf
}
task produceFile {
//... somehow create the file...
outputs.file file('path/to/file')
}
artifacts.add('myConf', produceFile.outputs.files.singleFile, { builtBy produceFile })
Is there a better way to declare the artifact than my clumsy version?
I couldn't figure out a way to pass the task dependency from the artifact to the producing task in one go.
According to the documentation article on Legacy publishing and the javadoc on the ArtifactHandler, for your simple example it should be sufficient to just pass the task, as long as the task type extends AbstractArchiveTask (e.g. Zip or Jar):
artifacts.add('myConf', produceFile)
... or in the more Gradle-ish way:
artifacts {
myConf produceFile
}
The article mentioned above has another example, where a File is passed directly to the add method, which requires you to specify the task to build the file in the way you did in your example.
However, let me propose other ideas for syntax that may be experienced more 'lightweight':
artifacts {
myConf files(produceFile).singleFile { buildBy produceFile }
// or
myConf file: files(produceFile).singleFile, buildBy: [produceFile]
}
These two examples use the Project.files(...) method to resolve the output(s) of the task instead of accessing them manually. The second example makes use of the map syntax often provided by Gradle.
If you want to somehow standardize your way to publish your custom artifacts, I would propose to create a custom task type that offers any of the different arguments the ArtifactHandler can process as a method or property:
class MyTaskType extends DefaultTask {
// ... other stuff ... of course this should be part of a plugin
def getArtifact() {
return ... // either a (Configurable)PublishArtifact (if constructor is available) or a map representation
}
}
task produceFile(type: MyTaskType) {
// configure somehow
}
artifacts {
myConf produceFile.artifact
}

How to update the <latest> tag in maven-metadata-local when installing an artifact?

In the project I am working on we have various multi-module projects being developed in parallel, some of which are dependent on others. Because of this we are using using version ranges, e.g. [0.0.1,), for our internal dependencies during development so that we can always work against the latest snapshot versions. (I understand that this isn't considered best practice, but for now at least we are stuck with the current project structure.) We have build profiles set up so that when we perform a release all the version ranges get replaced with RELEASE to compile against the latest released version.
We have to use ranges as opposed to LATEST because when installing an artifact locally, the <latest> tag inside maven-metadata-local.xml is never updated, and so specifying LATEST will get the last version deployed to our Artifactory server. The problem with the ranges though is that the build process seems to have to download all the metadata files for all the versions of an artifact to be able to determine the latest version. As our project goes on we are accumulating more and more versions and artifacts so our builds are taking longer and longer. Specifying LATEST avoids this but means that changes from local artifact installs are generally not picked up.
Is there any way to get the <latest> tag in the maven-metadata-local.xml file to be updated when installing an artifact locally?
If you are working with SNAPSHOT's you don't need version ranges apart from that never use version ranges (only in extrem rare situtions). With version ranges your build is not reproducible which should be avoided in my opinion under any circumstance.
But you can use things like this:
<version>[1.2.3,)</version
but as you already realized that caused some problems, but I would suggest to use the versions-maven-plugin as an alternative to update the projects pom files accordingly.
mvn clean versions:use-latest-versions scm:checkin deploy -Dmessage="update versions" -DperformRelease=true
This can be handled by CI solution like Jenkins. But I got the impression that you are doing some basic things wrong. In particular if you need to use version ranges.
I had the same problem, so I wrote a maven plugin to handle it for me. It's a pretty extreme workaround, but it does work.
The documentation for creating maven plugins is on The Apache Maven Project. You could just create a plugin project from the command line archetype and add this mojo to your project.
/**
* Inserts a "latest" block into the maven-metadata-local.xml in the user's local
* repository using the currently configured version number.
*
* #version Sep 23, 2013
*/
#Mojo( name = "latest-version", defaultPhase = LifecyclePhase.INSTALL )
public class InstallLatestVersionMojo extends AbstractMojo {
/**
* Location of the .m2 directory
*/
#Parameter( defaultValue = "/${user.home}/.m2/repository", property = "outputDir", required = true )
private File repositoryLocation;
#Parameter( defaultValue = "${project.groupId}", property = "groupId", required = true )
private String groupId;
#Parameter( defaultValue = "${project.artifactId}", property = "artifactId", required = true )
private String artifactId;
/**
* Version to use as the installed version
*/
#Parameter( defaultValue = "${project.version}", property = "version", required = true )
private String version;
public void execute() throws MojoExecutionException, MojoFailureException {
try {
// Fetch the xml file to edit from the user's repository for the project
File installDirectory = getInstallDirectory(repositoryLocation, groupId, artifactId);
File xmlFile = new File(installDirectory, "maven-metadata-local.xml");
Document xml = getXmlDoc(xmlFile);
if (xml != null) {
// Fetch the <latest> node
Node nodeLatest = getNode(xml, "/metadata/versioning/latest");
if (nodeLatest == null) {
// If <latest> does not yet exist, insert it into the <versioning> block before <versions>
nodeLatest = xml.createElement("latest");
Node versioningNode = getNode(xml, "/metadata/versioning");
if (versioningNode != null) {
versioningNode.insertBefore(nodeLatest, getNode(xml, "metadata/versioning/versions"));
}
}
// set the version on the <latest> node to the newly installed version
nodeLatest.setTextContent(version);
// save the xml
save(xmlFile, xml);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private void save(File xmlFile, Document xml) throws TransformerFactoryConfigurationError, TransformerException {
Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
Result output = new StreamResult(xmlFile);
Source input = new DOMSource(xml);
transformer.transform(input, output);
}
private Node getNode(Document source, String path) throws XPathExpressionException{
Node ret = null;
XPathExpression xPath = getPath(path);
NodeList nodes = (NodeList) xPath.evaluate(source, XPathConstants.NODESET);
if(nodes.getLength() > 0 ) {
ret = nodes.item(0);
}
return ret;
}
private XPathExpression getPath(String path) throws XPathExpressionException{
XPath xpath = XPathFactory.newInstance().newXPath();
return xpath.compile(path);
}
private File getInstallDirectory(File repositoryLocation, String groupId, String artifactId) {
String group = groupId.replace('.', '/');
return new File(repositoryLocation, group + "/" + artifactId);
}
private Document getXmlDoc(File xmlFile) throws ParserConfigurationException, SAXException, IOException {
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
return dBuilder.parse(xmlFile);
}
}
How about defining those internal dependencies as modules in one reactor pom? That way you'll compile against the compiled sources (in target/classes) instead of against a jar, and you'll always have the latest code.

How to programmatically list all transitive dependencies, including overridden ones in Maven using DependencyGraphBuilder?

This is similar to other questions (like this), but I want to be able to do this with the latest API's. The maven-dependency-plugin:tree verbose option has been deprecated and does nothing in the latest (2.5.1) code, so there is no good example of how to do it.
I believe Aether utility class from jcabi-aether can help you to get a list of all dependencies of any Maven artifact, for example:
File repo = this.session.getLocalRepository().getBasedir();
Collection<Artifact> deps = new Aether(this.getProject(), repo).resolve(
new DefaultArtifact("junit", "junit-dep", "", "jar", "4.10"),
JavaScopes.RUNTIME
);
If you're outside of Maven plugin:
File repo = new File("/tmp/local-repository");
MavenProject project = new MavenProject();
project.setRemoteProjectRepositories(
Arrays.asList(
new RemoteRepository(
"maven-central",
"default",
"http://repo1.maven.org/maven2/"
)
)
);
Collection<Artifact> deps = new Aether(project, repo).resolve(
new DefaultArtifact("junit", "junit-dep", "", "jar", "4.10"),
"runtime"
);
The only dependency you need is:
<dependency>
<groupId>com.jcabi</groupId>
<artifactId>jcabi-aether</artifactId>
<version>0.7.5</version>
</dependency>
Including my approach here, as the additional steps may become part of your actual use case, esp. if working on a composite or multi-module project.
(Maven 3, my runtime was 3.6; no direct dependency on Aether)
In my case I wanted to resolve the dependency tree of a specific artifact foo-runtime from inside my plugin; however,
some of the dependency versions were only available in its parent's foo-parent POM (i.e. absent in the foo-runtime's own POM).
The parent POM also had additional details, such as exclusions for some of foo-runtime's dependencies - via dependencyManagement.
So I had to:
explicitly load the parent's model,
link the child model to it,
fill in the missing version numbers of the child model (still not sure why Maven didn't automatically resolve these after linking the parent), and then
run dependency resolution for the child.
To avoid model building from scratch, I derived the model of of foo-runtime using an existing artifact foo-api (which in my case is always guaranteed to be present in the Maven project being built). All these artifacts share the same groupId.
#Component
public LifecycleDependencyResolver resolver;
// ...
// `artifacts` contains all artifacts of current/reactor `MavenProject` obtained via `project.getArtifacts()`
private Set<Artifact> resolveRuntimeDeps(Set<Artifact> artifacts) throws MojoExecutionException {
// foo-api will always be present; use it to derive coordinates for foo-runtime
Artifact fooApi = artifacts.stream().filter(artifact -> "foo-api".equals(artifact.getArtifactId()))
.findFirst().orElseThrow(() -> new MojoExecutionException("Unable to find foo-api"));
Collection<String> scopes = Arrays.asList("compile", "runtime");
MavenProject fooRoot = deriveProject(fooApi, "foo-parent");
Model fooRootPom = fooRoot.getModel();
MavenProject fooSrv = deriveProject(fooApi, "foo-runtime");
fooSrv.setParent(fooRoot);
// some foo-runtime deps depend on versions declared on parent pom; merge them
Map<String, Artifact> depMgt = fooRootPom.getDependencyManagement().getDependencies().stream()
.collect(Collectors.toMap(dep -> dep.getGroupId() + ":" + dep.getArtifactId() + ":" + dep.getType(), this::toArtifact));
for (Dependency d : fooSrv.getDependencies()) {
if (d.getVersion() == null) {
Artifact managed = depMgt.get(d.getGroupId() + ":" + d.getArtifactId() + ":" + d.getType());
if (managed != null) {
d.setVersion(managed.getVersion());
}
}
}
try {
resolver.resolveProjectDependencies(fooSrv, scopes, scopes, session, false, Collections.emptySet());
return fooSrv.getArtifacts();
} catch (LifecycleExecutionException e) {
throw new MojoExecutionException("Error resolving foo-runtime dependencies", e);
}
}
// load POM for another artifact based on foo-api JAR available in current project
private MavenProject deriveProject(Artifact fooApi, String artifactId) throws MojoExecutionException {
Model pom;
String pomPath = fooApi.getFile().getAbsolutePath().replaceAll("foo-api", artifactId).replaceAll("\\.jar$", ".pom");
try (InputStream fooRootPomData = new FileInputStream(pomPath)) {
pom = new MavenXpp3Reader().read(fooRootPomData);
pom.setPomFile(new File(pomPath));
} catch (IOException | XmlPullParserException e) {
throw new MojoExecutionException("Error loading " + artifactId + " metadata", e);
}
// set these params to avoid skips/errors during resolution
MavenProject proj = new MavenProject(pom);
proj.setArtifact(toArtifact(pom));
proj.setArtifactFilter(Objects::nonNull);
proj.setRemoteArtifactRepositories(Collections.emptyList());
return proj;
}
private Artifact toArtifact(Model model) {
return new DefaultArtifact(
Optional.ofNullable(model.getGroupId()).orElseGet(() -> model.getParent().getGroupId()), model.getArtifactId(),
Optional.ofNullable(model.getVersion()).orElseGet(() -> model.getParent().getVersion()), "compile", model.getPackaging(), null,
project.getArtifact().getArtifactHandler());
}
private Artifact toArtifact(Dependency dep) {
return new DefaultArtifact(dep.getGroupId(), dep.getArtifactId(), dep.getVersion(), dep.getScope(), dep.getType(), dep.getClassifier(),
project.getArtifact().getArtifactHandler());
}
(I tried almost all the other suggested approaches, however all of them ended up with some error or another. Now, looking back, I suspect many of those errors might have been due to the fact that my leaf POM was missing version numbers for some artifacts. It seems (acceptably so) the "model enrichment" phase - propagating parent versions etc. - is carried out by some earlier component in Maven's flow; and the caller has to take care of this, at least partially, when invoking the dependency resolver from scratch.)

Maven plugin artifact filter unimportant dependencies

I'm developing a Maven plugin and using the MavenProject object to access my dependencies with project.getDependencyArtifacts(), but this gives my all jar, even the test only jars.
Is there some method to filter all non runtime jar? If I just get the scope and compare for scope.equals("runtime") I will throw out the compile and other important dependencies.
I did not find an existing method for this either so I'm using the following logic. This is a plugin building a customized ear, which adds the needed dependencies to an xml file and include them in the archive. It is using getArtifacts instead of getDependencyArtifacts since I'm also interested in transitive dependencies.
Collection<Artifact> dependencies = new ArrayList<Artifact>();
dependencies.addAll(project.getArtifacts());
for (Iterator<Artifact> it=dependencies.iterator(); it.hasNext(); ) {
Artifact dependency = it.next();
String scope = dependency.getScope();
String type = dependency.getType();
if (dependency.isOptional() || !"jar".equals(type) || "provided".equals(scope) || "test".equals(scope) || "system".equals(scope)) {
getLog().debug("Pruning dependency " + dependency);
it.remove();
}
}

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