Creating correct Maven dependencies from Gradle

Question

After some hours of search and research I came up with a working example for writing the correct Maven dependencies into the generated pom.xml when using Gradle 1.11 and maven-publish plugin.

The first problem I faced was the provided dependency that always was written as runtime into the pom.xml

The second problem was the dynamic version, that I use for minor version changes. Maven and Gradle have different notations and the maven-publish simply writes the Gradle kind of notation into the pom.xml

Here is my example:

apply plugin: 'java'
apply plugin: 'maven-publish'

group = 'de.pentos'
version = '0.4.4'
sourceCompatibility = 1.7
repositories {
    mavenCentral()
    mavenLocal()
}
configurations {
    provided
    compile.extendsFrom provided
}
dependencies {
    provided("org.projectlombok:lombok:1.+")
    provided("javax.servlet:javax.servlet-api:3.1.0")

    compile("org.slf4j:slf4j-api:1.7+")
    compile("com.fasterxml.jackson.core:jackson-databind:2.3.+")
    compile("joda-time:joda-time:2.3+")
    compile("org.springframework:spring-webmvc:3.2+")
    compile("org.springframework.security:spring-security-web:3.1+")

    testCompile("junit:junit:4.11")
}
jar { baseName = "${project.group}.${project.name}" }
publishing {
    publications {
        jar(MavenPublication) {
            from components.java
            artifactId "${project.name}"
            artifact sourceJar { classifier "sources" }
            pom.withXml {
                final Node root = asNode()
                final versionPattern = ~/(?:(.+)\.)?(.+?)\.?\+/
                configurations.compile.allDependencies.each {
                    final name = it.name
                    final group = it.group
                    final m = versionPattern.matcher(it.version)
                    if (m.matches()) {
                        final base = m[0][1]
                        final rest = m[0][2].toInteger()
                        final version = '[' + (base ? base + '.' : '') + (rest) + ',' + (base ? base + '.' : '') + (rest + 1) + ')'
                        root.dependencies.first().findAll{
                            it.groupId.first().value()[0] == group && it.artifactId.first().value()[0] == name
                        }.each {
                            it.version.first().value = version
                        }
                    }
                }
                configurations.provided.allDependencies.each {
                    final name = it.name
                    final group = it.group
                    root.dependencies.first().findAll{
                        it.groupId.first().value()[0] == group && it.artifactId.first().value()[0] == name
                    }.each {
                        it.scope.first().value = 'provided'
                    }
                }
            }
        }
    }
}
tasks.withType(Compile) { options.encoding = 'UTF-8' }
task sourceJar(type: Jar) {
    classifier = 'sources'
    from sourceSets.main.allSource
}

So what is my Question?

I had some trouble with a lot examples that simply compared

..findAll {
    it.groupId == group
}

This hadn't worked for me and I had to find out by lot of testing how to get the findAll to work.
So is my version to detailed? Can it be written with less code?

Can I extract the functionality for dependency management into a more system wide script, that can be reused from all other projects, that need this dependency management? How?

During compileJava I get the warning :compileJavawarning: [options] bootstrap class path not set in conjunction with -source 1.7
What does this mean, and how can I fix that.

Answer 1

I had some trouble with a lot examples that simply compared [...]

it.groupId is not a String. You'll need something like it.groupId.value(), or perhaps it.groupId[0].value().

Can I extract the functionality for dependency management into a more system wide script, that can be reused from all other projects, that need this dependency management? How?

You can write a plugin class, and ship it to builds as a Jar. For details, see the Gradle User Guide.

During compileJava I get the warning :compileJavawarning: [options] bootstrap class path not set in conjunction with -source 1.7 What does this mean, and how can I fix that.

This question has been asked and answered many times already. See Stack Overflow or http://forums.gradle.org.

PS: Instead of rewriting Ivy to Maven version range syntax, it should be possible to use Maven syntax from the start (i.e. in the build script).