diff -r f497cf8621b3 -r e8eb755f0099 samples/singletons/src/org/apidesign/singletons/impl/SwingDialogDisplayer.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/samples/singletons/src/org/apidesign/singletons/impl/SwingDialogDisplayer.java	Tue Feb 02 10:24:49 2010 +0100
@@ -0,0 +1,16 @@
+package org.apidesign.singletons.impl;
+
+import javax.swing.JOptionPane;
+import org.apidesign.singletons.api.DialogDisplayer;
+import org.openide.util.lookup.ServiceProvider;
+
+// BEGIN: singletons.injectable.implement
+@ServiceProvider(service=DialogDisplayer.class)
+public final class SwingDialogDisplayer extends DialogDisplayer {
+    @Override
+    public boolean yesOrNo(String query) {
+        final int res = JOptionPane.showConfirmDialog(null, query);
+        return res == JOptionPane.OK_OPTION;
+    }
+}
+// END: singletons.injectable.implement