VersionHelper.valueOf now returns an Optional (WIP 1/3)

This helps to avoid bugs similar to #7917

Author: cmaglie

Diff for: arduino-core/src/cc/arduino/contributions/DownloadableContribution.java

@@ -32,6 +32,7 @@
 import com.github.zafarkhaja.semver.Version;
 
 import java.io.File;
+import java.util.Optional;
 
 public abstract class DownloadableContribution {
 
@@ -66,10 +67,10 @@ public void setDownloadedFile(File downloadedFile) {
   }
 
   public String getParsedVersion() {
-    Version version = VersionHelper.valueOf(getVersion());
-    if (version == null) {
-      return null;
+    Optional<Version> version = VersionHelper.valueOf(getVersion());
+    if (version.isPresent()) {
+      return version.get().toString();
     }
-    return version.toString();
+    return null;
   }
 }

Diff for: arduino-core/src/cc/arduino/contributions/VersionHelper.java

@@ -29,13 +29,15 @@
 
 package cc.arduino.contributions;
 
+import java.util.Optional;
+
 import com.github.zafarkhaja.semver.Version;
 
 public class VersionHelper {
 
-  public static Version valueOf(String ver) {
+  public static Optional<Version> valueOf(String ver) {
     if (ver == null) {
-      return null;
+      return Optional.empty();
     }
     try {
       // Allow x.y-something, assuming x.y.0-something
@@ -49,18 +51,17 @@ public static Version valueOf(String ver) {
       }
       String[] parts = version.split("\\.");
       if (parts.length >= 3) {
-        return Version.valueOf(ver);
+        return Optional.of(Version.valueOf(ver));
       }
       if (parts.length == 2) {
         version += ".0";
       }
       if (parts.length == 1) {
         version += ".0.0";
       }
-      return Version.valueOf(version + extra);
+      return Optional.of(Version.valueOf(version + extra));
     } catch (Exception e) {
-      System.err.println("Invalid version found: " + ver);
-      return null;
+      return Optional.empty();
     }
   }