[[sec:module_dependencies_java_tutorial]]
== Declaring module dependencies

There are various <<declaring_dependencies.adoc#sec:dependency-types,types of dependencies>> that you can declare.
One such type is a _module dependency_.
A <<declaring_dependencies.adoc#sub:module_dependencies,module dependency>> represents a dependency on a module with a specific version built outside the current build.

=== Identity values for the published project

The generated Ivy module descriptor file contains an `<info>` element that identifies the module. The default identity values are derived from the following:

* `organisation` - link:{groovyDslPath}/org.gradle.api.Project.html#org.gradle.api.Project:group[Project.getGroup()]
* `module` - link:{groovyDslPath}/org.gradle.api.Project.html#org.gradle.api.Project:name[Project.getName()]

        val visited = hashSetOf<KtModule>()
        val stack = ktModules.toMutableList()
        while (stack.isNotEmpty()) {
            val module = stack.popLast()
            if (module in visited) continue
            visited += module
            for (dependency in module.allDependencies()) {
                if (dependency !in visited) {
                    stack += dependency
                }
            }
        }

// It also returns the modroot of the module providing the replacement if
// one was found.
func resolveReplacement(m module.Version) module.Version {
	if r := Replacement(m); r.Path != "" {
		return r
	}
	return m
}

func toReplaceMap(replacements []*modfile.Replace) map[module.Version]module.Version {
	replaceMap := make(map[module.Version]module.Version, len(replacements))
	for _, r := range replacements {

        def excludeArgs2 = WrapUtil.toMap("module", "aModule")

        when:
        dependency.exclude(excludeArgs1)
        dependency.exclude(excludeArgs2)

        then:
        dependency.excludeRules.size() == 2
        dependency.excludeRules.contains(new DefaultExcludeRule("aGroup", null))
        dependency.excludeRules.contains(new DefaultExcludeRule(null, "aModule"))
    }

    void "can add artifacts"() {

        <!--</module>-->

        <!-- Coding -->
        <module name="CovariantEquals"/>
        <module name="DefaultComesLast"/>
        <module name="EmptyStatement"/>
        <module name="EqualsHashCode"/>
        <module name="ExplicitInitialization"/>
        <module name="MultipleVariableDeclarations"/>
        <module name="NoClone"/>
        <module name="NoFinalizer"/>

        allProjects.rootIdeaProject.name == 'module-main'
        allProjects.rootIdeaProject.modules.collect { it.name } == ['module-main', 'module-main-module-b']

        allProjects.getIdeaProject('module-main').modules.collect { it.name } == ['module-main', 'module-main-module-b']

            rootProject.name = 'module-root'
            includeBuild('module-a')
        """
        file('module-a').mkdir()
        file('module-b').mkdir()
        file('module-c').mkdir()
        file('module-a/settings.gradle') << """
            includeBuild('../module-b')
        """
        file('module-b/settings.gradle') << """
            includeBuild('../module-c')
        """

        def module1Dir = createModule("some-module", properties(projects: 'gradle-module-2'))
        def module2Dir = createModule("module-2", properties())
        def registry = defaultModuleRegistryFor([module1Dir, module2Dir])

        expect:
        def module = registry.getModule("gradle-some-module")
        module.requiredModules as List == [registry.getModule("gradle-module-2")]
    }

        def inDefault = ivyRepo.module("org.test", "in-default", "1.0").publish()
        def m1 = ivyRepo.module("org.test", "m1", "1.0")
            .configuration("compile")
            .publish()
        def m2 = ivyRepo.module("org.test", "m2", "1.0").publish()
        def m3 = ivyRepo.module("org.test", "m3", "1.0")