"'${id}' { id='${id}'; implementationClass='${packageName}.${className}' }"
                    }.join("\n")}
                }
            }
        """
    }

    PluginBuilder addPluginSource(String id, String className, @GroovyBuildScriptLanguage String impl) {
        addPluginId(id, className)
        groovy("${className}.groovy") << impl
        this
    }

        if (added) {
            return
        }
        added = true
        def builder = new PluginBuilder(projectDir.file('plugin-' + id))
        builder.packageName = packageName
        builder.addPluginSource(id, simpleClassName, """
            package $builder.packageName

            class ${simpleClassName} implements $Plugin.name<$Settings.name> {
                void apply($Settings.name settings) {