refactor(gradle): Turn extension functions into properties

This simplifies the code a bit.

Signed-off-by: Sebastian Schuberth <[email protected]>

plugins/package-managers/gradle-model/src/main/kotlin/Extensions.kt

@@ -22,17 +22,18 @@ package org.ossreviewtoolkit.plugins.packagemanagers.gradlemodel
 import OrtDependency
 
 /**
- * Determine the type of this Gradle dependency. In case of a project, it is "Gradle". Otherwise it is "Maven" unless
- * there is no POM, then it is "Unknown".
+ * The type of this Gradle dependency. In case of a project, it is "Gradle". Otherwise it is "Maven" unless there is no
+ * POM, then it is "Unknown".
  */
-fun OrtDependency.dependencyType(): String =
-    if (isProjectDependency()) {
+val OrtDependency.dependencyType: String
+    get() = if (isProjectDependency) {
         "Gradle"
     } else {
         pomFile?.let { "Maven" } ?: "Unknown"
     }
 
 /**
- * Return true if this Gradle dependency refers to another project, or false if it refers to a package.
+ * A flag to indicate whether this Gradle dependency refers to a project, or to a package.
  */
-fun OrtDependency.isProjectDependency() = localPath != null
+val OrtDependency.isProjectDependency: Boolean
+    get() = localPath != null

plugins/package-managers/gradle/src/main/kotlin/GradleDependencyHandler.kt

@@ -60,7 +60,7 @@ internal class GradleDependencyHandler(
 
     override fun identifierFor(dependency: OrtDependency): Identifier =
         Identifier(
-            type = dependency.dependencyType(),
+            type = dependency.dependencyType,
             namespace = dependency.groupId,
             name = dependency.artifactId,
             version = dependency.version
@@ -88,11 +88,11 @@ internal class GradleDependencyHandler(
         )
 
     override fun linkageFor(dependency: OrtDependency): PackageLinkage =
-        if (dependency.isProjectDependency()) PackageLinkage.PROJECT_DYNAMIC else PackageLinkage.DYNAMIC
+        if (dependency.isProjectDependency) PackageLinkage.PROJECT_DYNAMIC else PackageLinkage.DYNAMIC
 
     override fun createPackage(dependency: OrtDependency, issues: MutableCollection<Issue>): Package? {
         // Only look for a package if there was no error resolving the dependency and it is no project dependency.
-        if (dependency.error != null || dependency.isProjectDependency()) return null
+        if (dependency.error != null || dependency.isProjectDependency) return null
 
         val artifact = DefaultArtifact(
             dependency.groupId, dependency.artifactId, dependency.classifier,