Merge pull request #330 from brunobowden/refactor

Minimum Gradle Version check: 2.4

Author: brunobowden

src/main/groovy/com/github/j2objccontrib/j2objcgradle/J2objcPlugin.groovy

@@ -30,6 +30,7 @@ import org.gradle.api.Plugin
 import org.gradle.api.Project
 import org.gradle.api.Task
 import org.gradle.api.logging.LogLevel
+import org.gradle.util.GradleVersion
 
 /*
  * Main plugin class for creation of extension object and all the tasks.
@@ -40,6 +41,8 @@ class J2objcPlugin implements Plugin<Project> {
     void apply(Project project) {
         // This avoids a lot of "project." prefixes, such as "project.tasks.create"
         project.with {
+            Utils.checkMinGradleVersion(GradleVersion.current())
+
             extensions.create('j2objcConfig', J2objcConfig, project)
 
             afterEvaluate { Project evaluatedProject ->

src/main/groovy/com/github/j2objccontrib/j2objcgradle/tasks/Utils.groovy

@@ -34,6 +34,7 @@ import org.gradle.api.tasks.WorkResult
 import org.gradle.process.ExecResult
 import org.gradle.process.ExecSpec
 import org.gradle.process.internal.ExecException
+import org.gradle.util.GradleVersion
 
 import java.util.regex.Matcher
 
@@ -48,6 +49,17 @@ class Utils {
     // TODO: ideally bundle j2objc binaries with plugin jar and load at runtime with
     // TODO: ClassLoader.getResourceAsStream(), extract, chmod and then execute
 
+    // Prevent construction of this class, confines usage to static methods
+    private Utils() { }
+
+    static void checkMinGradleVersion(GradleVersion gradleVersion) {
+        final GradleVersion minGradleVersion = GradleVersion.version('2.4')
+        if (gradleVersion.compareTo(minGradleVersion) < 0) {
+            throw new InvalidUserDataException(
+                    "J2ObjC Gradle Plugin requires minimum Gradle version: $minGradleVersion")
+        }
+    }
+
     static boolean isWindows() {
         return System.getProperty('os.name').toLowerCase().contains('windows')
     }

src/test/groovy/com/github/j2objccontrib/j2objcgradle/tasks/UtilsTest.groovy

@@ -26,6 +26,7 @@ import org.gradle.api.plugins.JavaPlugin
 import org.gradle.process.ExecSpec
 import org.gradle.process.internal.ExecHandleBuilder
 import org.gradle.testfixtures.ProjectBuilder
+import org.gradle.util.GradleVersion
 import org.junit.Before
 import org.junit.Rule
 import org.junit.Test
@@ -47,6 +48,20 @@ class UtilsTest {
         proj = ProjectBuilder.builder().build()
     }
 
+    @Test
+    void testCheckMinGradleVersion_valid() {
+        Utils.checkMinGradleVersion(GradleVersion.version('2.4'))
+        Utils.checkMinGradleVersion(GradleVersion.version('2.4.1'))
+        Utils.checkMinGradleVersion(GradleVersion.version('2.5'))
+        Utils.checkMinGradleVersion(GradleVersion.version('3.0'))
+        Utils.checkMinGradleVersion(GradleVersion.version('10.0'))
+    }
+
+    @Test(expected=InvalidUserDataException)
+    void testCheckMinGradleVersion_invalid() {
+        Utils.checkMinGradleVersion(GradleVersion.version('2.3'))
+    }
+
     @Test
     void testIsWindows() {
         // TODO: also test for correctness
@@ -118,7 +133,7 @@ class UtilsTest {
         localProperties.write('j2objc.written-invalid-key')
 
         expectedException.expect(InvalidUserDataException.class)
-        expectedException.expectMessage('Invalid j2objc property: j2objc.written-invalid-key')
+        expectedException.expectMessage('Invalid J2ObjC Gradle Plugin property: j2objc.written-invalid-key')
         expectedException.expectMessage("From local.properties: $proj.projectDir/local.properties")
         // Check list of valid keys is suggested by checking for a single entry:
         expectedException.expectMessage('debug.enabled')