refactor: introduces staged builder patterns for frege project setup

(WIP)

1 files changed, 41 insertions, 13 deletions

diff --git a/src/main/java/ch/fhnw/thga/gradleplugins/SetupFregeTask.java b/src/main/java/ch/fhnw/thga/gradleplugins/SetupFregeTask.java
index 6bfe72d..c4e17d3 100644
--- a/src/main/java/ch/fhnw/thga/gradleplugins/SetupFregeTask.java
+++ b/src/main/java/ch/fhnw/thga/gradleplugins/SetupFregeTask.java
@@ -6,6 +6,7 @@ import java.net.URL;
 import java.nio.channels.Channels;
 import java.nio.channels.FileChannel;
 import java.nio.channels.ReadableByteChannel;
+import java.nio.file.Paths;
 
 import org.gradle.api.DefaultTask;
 import org.gradle.api.GradleException;
@@ -36,32 +37,59 @@ public abstract class SetupFregeTask extends DefaultTask {
     public abstract DirectoryProperty getDownloadDir();
 
     @Internal
-    public Provider<String> getFregeVersionJarName() {
+    public Provider<String> getFregeVersionJarName()
+    {
         return getVersion().map(version -> "frege" + version + ".jar");
     }
 
     @Internal
-    final public Provider<String> getDownloadUrl() {
+    final public Provider<String> getDownloadUrl()
+    {
         return getFregeVersionJarName()
-                .map(name -> String.join("/", FREGE_GITHUB_URL_PREFIX, getRelease().get(), name));
+            .map(name -> String.join("/", FREGE_GITHUB_URL_PREFIX, getRelease().get(), name));
     }
 
     @OutputFile
-    public Provider<RegularFile> getFregeCompilerOutputPath() {
+    public Provider<RegularFile> getFregeCompilerOutputPath()
+    {
         return getDownloadDir().file(getFregeVersionJarName());
     }
 
     @TaskAction
     public void downloadFregeCompiler() {
-        String fregeCompilerOutputPath = getFregeCompilerOutputPath().get().getAsFile().getAbsolutePath();
-        try (ReadableByteChannel readChannel = Channels.newChannel(new URL(getDownloadUrl().get()).openStream());
-                FileOutputStream fregeCompilerOutputStream = new FileOutputStream(fregeCompilerOutputPath);) {
-            FileChannel writeChannel = fregeCompilerOutputStream.getChannel();
-            writeChannel.transferFrom(readChannel, 0, Long.MAX_VALUE);
-            LOGGER.lifecycle(String.format("Successfully downloaded %s to: %s", getFregeVersionJarName().get(),
-                    fregeCompilerOutputPath));
-        } catch (IOException e) {
+        String fregeCompilerOutputPath = getFregeCompilerOutputPath()
+            .get()
+            .getAsFile()
+            .getAbsolutePath();
+        if (Paths
+            .get(fregeCompilerOutputPath)
+            .toFile()
+            .exists()
+        )
+        return;
+
+        try (ReadableByteChannel readChannel = Channels
+                .newChannel(new URL(getDownloadUrl().get())
+                .openStream()
+            );
+            FileOutputStream fregeCompilerOutputStream = new FileOutputStream(
+                fregeCompilerOutputPath))
+            {
+                FileChannel writeChannel = fregeCompilerOutputStream.getChannel();
+                writeChannel.transferFrom(
+                    readChannel,
+                    0,
+                    Long.MAX_VALUE);
+                LOGGER.lifecycle(
+                    String.format(
+                        "Successfully downloaded %s to: %s",
+                        getFregeVersionJarName().get(),
+                        fregeCompilerOutputPath
+                    )
+                );
+        } catch (IOException e)
+        {
             throw new GradleException(e.getMessage());
         }
     }
-}
+}
\ No newline at end of file