Develop Reference

Access value of maven_jar.artifact from Skylark rule

In my Skylark rule, I am looking through all my deps - some of them are maven_jar instances defined in my WORKSPACE file. For those, I would like to access the value of maven_jar.artifact, but as far as I can tell it isn't available. Is it possible to get at that value?
For example, if my WORKSPACE has:
maven_jar(
name = "com_google_guava_guava",
artifact = "com.google.guava:guava:20.0",
)
And my BUILD file has something like this:
my_rule(
name = "foo",
deps = ["#com_google_guava_guava//jar"]
)
In the implementation of my_rule, I would like to get the value com.google.guava:guava:20.0.

I think you'll need to file a feature request for this:
https://github.com/bazelbuild/bazel/issues/new
The instance of the maven_jar rule in the workspace file isn't available to the rules in BUILD files, only the rules which the workspace rule generates are (i.e., #com_google_guava_guava//jar). Off the top of my head, maven_jar would have to generate a rule into the jar's workspace which has an attribute with the value of artifact, and that rule would need to create a provider containing that value for other rules to consume.
(There does happen to be META-INF/maven/com.google.guava/guava/pom.xml inside the jar, which seems to have the information you want, but I don't know if you can rely on that for all jars from maven, but either way, the contents of the jar aren't available at analysis time (within the rule implementation))

Get artifact for GAV from Artifactory

For given groupId, artifactId, version, classifier and type, how can I download the corresponding artifact using REST?

use the gavc search to get the URL and from there you can download the artefact:
GAVC Search
Description: Search by Maven coordinates: GroupId, ArtifactId, Version
& Classifier. Search must contain at least one argument. Can limit
search to specific repositories (local and remote-cache). Since: 2.2.0
Security: Requires a privileged user (can be anonymous) Usage: GET
/api/search/gavc?[g=groupId][&a=artifactId][&v=version][&c=classifier][&repos=x[,y]]
Headers (Optionally): X-Result-Detail: info (To add all extra
information of the found artifact), X-Result-Detail: properties (to
get the properties of the found artifact), X-Result-Detail: info,
properties (for both). Produces:
application/vnd.org.jfrog.artifactory.search.GavcSearchResult+json
Sample Output:
GET /api/search/gavc?g=org.acme&a=artifact&v=1.0&c=sources&repos=libs-release-local
{
"results": [
{
"uri": "http://localhost:8080/artifactory/api/storage/libs-release-local/org/acme/artifact/1.0/artifact-1.0-sources.jar"
},{
"uri": "http://localhost:8080/artifactory/api/storage/libs-release-local/org/acme/artifactB/1.0/artifactB-1.0-sources.jar"
}
]
}
Taken from the API-Documenation.

In the Artifactory docs about their REST service you have an example here: https://www.jfrog.com/confluence/display/RTF/Artifactory+REST+API#ArtifactoryRESTAPI-RetrieveArtifact

How to find PMD Rulesets names in Gradle >2.0

In Gradle's Java projects we can use PMD via pmd plugin. To configure the rules which we want to use can do it in two ways:
ruleSetFiles - The custom rule set files to be used. See the official documentation for how to author a rule set file. Example: ruleSetFiles = files("config/pmd/myRuleSet.xml")
ruleSetsThe built-in rule sets to be used. See the official list of built-in rule sets.
With ruleSetFiles there is no problem you can find the names of the rules and to add or exclude ones, but in the documentation there is no information about the ruleStes? From where to find the exact names? From what I found from another projects the names are similar to the names from the PMD documentation but lower case. For example:
Braces - > java-braces
Clone - > java-clone
Implementation - >java-implementation
Code Size - > java-codesize
But this like Security Code Guidelines do not transform in -> java-securitycodeguidelines but just in java-sunsecure. I found that the names which works with PMD 5.1.1. are:
pmd {
ruleSets = [
'java-android',
'java-basic',
'java-braces',
'java-clone',
'java-codesize',
'java-comments',
'java-controversial',
'java-coupling',
'java-design',
'java-empty',
'java-finalizers',
'java-imports',
'java-j2ee',
'java-javabeans',
'java-junit',
'java-logging-jakarta-commons',
'java-logging-java',
'java-migrating',
'java-naming',
'java-optimizations',
'java-strictexception',
'java-strings',
'java-sunsecure',
'java-typeresolution',
'java-unnecessary',
'java-unusedcode'
]
toolVersion = '5.1.1'
ignoreFailures = true
}
How to find mapping between PMD names which are shown in their documentation and Gradle names?

The docs for RuleSetReferenceId are helpful, as is I believe this directory in the source tree. Basically put java- in front of any of these files to turn on the rules there.

Human editable JSON-like or YAML-like program configuration in Java

Is there a Java library similar to libconfig for C++, where the config file is stored in a JSON-like format that can be edited by humans, and later read from the program?
I don't want to use Spring or any of the larger frameworks. What I'm looking for is a small, fast, self-contained library. I looked at java.util.Properties, but it doesn't seem to support hierarchical/nested config data.

I think https://github.com/typesafehub/config is exactly what you are looking for. The format is called HOCON for Human-Optimized Config Object Notation and it a super-set of JSON.
Examples of HOCON:
HOCON that is also valid JSON:
{
"foo" : {
"bar" : 10,
"baz" : 12
}
}
HOCON also supports standard properties format, so the following is valid as well:
foo.bar=10
foo.baz=12
One of the features I find very useful is inheritance, this allows you to layer configurations. For instance a library would have a reference.conf, and the application using the library would have an application.conf. The settings in the application.conf will override the defaults in reference.conf.
Standard Behavior for loading configs:
The convenience method ConfigFactory.load() loads the following
(first-listed are higher priority):
system properties application.conf (all resources on classpath with
this name)
application.json (all resources on classpath with this
name)
application.properties (all resources on classpath with this
name)
reference.conf (all resources on classpath with this name)

I found this HOCON example:
my.organization {
project {
name = "DeathStar"
description = ${my.organization.project.name} "is a tool to take control over whole world. By world I mean couch, computer and fridge ;)"
}
team {
members = [
"Aneta"
"Kamil"
"Lukasz"
"Marcin"
]
}
}
my.organization.team.avgAge = 26
to read values:
val config = ConfigFactory.load()
config.getString("my.organization.project.name") // => DeathStar
config.getString("my.organization.project.description") // => DeathStar is a tool to take control over whole world. By world I mean couch, computer and fridge ;)
config.getInt("my.organization.team.avgAge") // => 26
config.getStringList("my.organization.team.members") // => [Aneta, Kamil, Lukasz, Marcin]
Reference: marcinkubala.wordpress.com

Apache Commons Configuration API and Constretto seem to be somewhat popular and support multiple formats (no JSON mentioned, though). I've personally never tried either, so YMMV.

There's a Java library to handle JSON files if that's what you're looking for:
http://www.json.org/java/index.html
Check out other tools on the main page:
http://json.org/

buildr: package dependencies into a single jar

I have a java project that is built with buildr and that has some external dependencies:
repositories.remote << "http://www.ibiblio.org/maven2"
repositories.remote << "http://packages.example/"
define "myproject" do
compile.options.target = '1.5'
project.version = "1.0.0"
compile.with 'dependency:dependency-xy:jar:1.2.3'
compile.with 'dependency2:dependency2:jar:4.5.6'
package(:jar)
end
I want this to build a single standalone jar file that includes all these dependencies.
How do I do that?
(there's a logical followup question: How can I strip all the unused code from the included dependencies and only package the classes I actually use?)

This is what I'm doing right now. This uses autojar to pull only the necessary dependencies:
def add_dependencies(pkg)
tempfile = pkg.to_s.sub(/.jar$/, "-without-dependencies.jar")
mv pkg.to_s, tempfile
dependencies = compile.dependencies.map { |d| "-c #{d}"}.join(" ")
sh "java -jar tools/autojar.jar -baev -o #{pkg} #{dependencies} #{tempfile}"
end
and later:
package(:jar)
package(:jar).enhance { |pkg| pkg.enhance { |pkg| add_dependencies(pkg) }}
(caveat: I know little about buildr, this could be totally the wrong approach. It works for me, though)

I'm also learning Buildr and currently I'm packing Scala runtime with my application this way:
package(:jar).with(:manifest => _('src/MANIFEST.MF')).exclude('.scala-deps')
.merge('/var/local/scala/lib/scala-library.jar')
No idea if this is inferior to autojar (comments are welcome), but seems to work with a simple example. Takes 4.5 minutes to package that scala-library.jar thought.

I'm going to use Cascading for my example:
cascading_dev_jars = Dir[_("#{ENV["CASCADING_HOME"]}/build/cascading-{core,xml}-*.jar")]
#...
package(:jar).include cascading_dev_jars, :path => "lib"

Here is how I create an Uberjar with Buildr, this customization of what is put into the Jar and how the Manifest is created:
assembly_dir = 'target/assembly'
main_class = 'com.something.something.Blah'
artifacts = compile.dependencies
artifacts.each do |artifact|
Unzip.new( _(assembly_dir) => artifact ).extract
end
# remove dirs from assembly that should not be in uberjar
FileUtils.rm_rf( "#{_(assembly_dir)}/example/package" )
FileUtils.rm_rf( "#{_(assembly_dir)}/example/dir" )
# create manifest file
File.open( _("#{assembly_dir}/META-INF/MANIFEST.MF"), 'w') do |f|
f.write("Implementation-Title: Uberjar Example\n")
f.write("Implementation-Version: #{project_version}\n")
f.write("Main-Class: #{main_class}\n")
f.write("Created-By: Buildr\n")
end
present_dir = Dir.pwd
Dir.chdir _(assembly_dir)
puts "Creating #{_("target/#{project.name}-#{project.version}.jar")}"
`jar -cfm #{_("target/#{project.name}-#{project.version}.jar")} #{_(assembly_dir)}/META-INF/MANIFEST.MF .`
Dir.chdir present_dir
There is also a version that supports Spring, by concatenating all the spring.schemas