Update build.gradle to use AWT to ask for passphrase

build.gradle

@@ -1,3 +1,6 @@
+import groovy.swing.SwingBuilder
+import java.awt.Point
+
 buildscript {
   repositories {
     mavenCentral()
@@ -77,22 +80,6 @@ jar {
   }
 }
 
-// I refuse to put my PGP password in a file, so there's no way to
-// make this work from a CI environment.
-gradle.taskGraph.whenReady { taskGraph ->
-    if (taskGraph.hasTask(":uploadArchives")) {
-        Console console = System.console()
-        console.printf "\n\nWe have to sign some things in this build." +
-                       "\n\nPlease enter your signing details.\n\n"
-
-        def password = console.readPassword("PGP Private Key Password: ")
-
-        allprojects { ext."signing.password" = password }
-
-        console.printf "\nThanks.\n\n"
-    }
-}
-
 task copyNotices(type: Copy) {
   from 'resources/notices'
   into 'build/dist/docs/notices'
@@ -162,6 +149,57 @@ signing {
   sign configurations.archives
 }
 
+// I refuse to put my PGP password in a file.
+//
+// Adapted from
+// https://www.timroes.de/2014/01/19/using-password-prompts-with-gradle-build-files/
+//
+// N.B. This can't work in a CI environment so there's no way to
+// automatically publish the artifacts from, for example, Travis CI.
+//
+gradle.taskGraph.whenReady { taskGraph ->
+  if(taskGraph.hasTask(':uploadArchives')) {
+
+    def pass = ''
+    if(System.console() == null) {
+      new SwingBuilder().edt {
+        dialog(modal: true,
+            title: 'Enter password',
+            alwaysOnTop: true,
+            resizable: false,
+            locationRelativeTo: null,
+            locationByPlatform: true,
+            // On my Linux multi-monitor setup, the dialog "appears" at
+            // the top of the virtual desktop below my desktop. So move
+            // the damned thing somewhere visible. Meh.
+            location: new Point(100,100),
+            pack: true,
+            show: true
+        ) {
+          vbox { //
+            label(text: "Please enter key passphrase:")
+            input = passwordField()
+            button(defaultButton: true, text: 'OK', actionPerformed: {
+              pass = input.password;
+              dispose();
+            })
+          }
+        }
+      }
+    } else {
+      pass = System.console().readPassword("\nPlease enter key passphrase: ")
+      pass = new String(pass)
+    }
+
+    if (pass.size() <= 0) {
+      throw new InvalidUserDataException("You must enter a password to proceed.")
+    }
+
+    allprojects { ext."signing.password" = pass }
+
+  }
+}
+
 uploadArchives {
   repositories {
     mavenDeployer {