test(java-oracle): measure the getter defaults XMLEncoder refers to

XMLEncoder shares equal Integer objects, so a node's x coordinate can be
written as a reference to the result of JSidebarButton.getIconTextGap().
GetterDefaults constructs the classes like XMLDecoder does and records
what the getters return (packages/fls/src/javaDefaults.json).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tools/java-oracle/README.md

@@ -22,3 +22,15 @@ virtuellen Bildschirm statt „headless".
 * Bisher ausgelesen: Geräte (Klasse, Name, Beschriftung, Position,
   Schnittstellen), Kabel (Enden als Gerät/Schnittstelle), Doku-Elemente.
   Systemsoftware, Dateisysteme und Anwendungen folgen schrittweise.
+
+## Getter-Standardwerte
+
+XMLEncoder teilt gleiche `Integer`/`Boolean`-Objekte. Ein Wert, der einmal als
+Ergebnis eines Getters geschrieben wurde (`<void id="Integer0"
+property="iconTextGap"/>`), taucht später nur noch als Verweis auf — etwa als
+x-Koordinate eines Geräts. Daran scheitert der Swift-Leser (Plan §13, M2).
+
+`GetterDefaults` erzeugt die betroffenen Klassen wie XMLDecoder (ohne
+Argumente) und ruft den Getter auf; das Ergebnis steht in
+`packages/fls/src/javaDefaults.json`. Gemessen, nicht geraten: Filius' Knopf
+setzt `verticalTextPosition` auf 3 (BOTTOM), nicht auf Swings 0 (CENTER).

tools/java-oracle/run.sh

@@ -21,7 +21,7 @@ if [ ! -f "$upstream/target/filius.jar" ]; then
 fi
 classpath="$upstream/target/filius.jar:$upstream/target/lib/*"
 mkdir -p "$here/.build"
-javac -d "$here/.build" -cp "$classpath" "$here/src/FlsOracle.java"
+javac -encoding UTF-8 -d "$here/.build" -cp "$classpath" "$here/src/FlsOracle.java" "$here/src/GetterDefaults.java"
 # FILIUS writes its settings below $HOME; keep them out of the real one.
 mkdir -p "$here/.build/home"
 # Removed first: a crashed run must not leave the previous result standing.
@@ -29,3 +29,25 @@ rm -f "$root/corpus/corpus.java.json"
 HOME="$here/.build/home" xvfb-run -a java -cp "$classpath:$here/.build" FlsOracle \
     "$root/corpus" "$root/corpus/corpus.java.json" 2>&1 | grep -v 'logback\|^$' || true
 test -s "$root/corpus/corpus.java.json"
+
+# Getter defaults for the XMLEncoder references (packages/fls/src/javaDefaults.json).
+defaults="$root/packages/fls/src/javaDefaults.json"
+rm -f "$defaults"
+HOME="$here/.build/home" xvfb-run -a java -cp "$classpath:$here/.build" GetterDefaults "$defaults" \
+    filius.gui.netzwerksicht.JSidebarButton#iconTextGap \
+    filius.gui.netzwerksicht.JSidebarButton#verticalTextPosition \
+    filius.gui.netzwerksicht.JSidebarButton#displayedMnemonicIndex \
+    filius.gui.netzwerksicht.JSidebarButton#debugGraphicsOptions \
+    filius.gui.netzwerksicht.JSidebarButton#enabled \
+    java.lang.ThreadGroup#maxPriority \
+    filius.hardware.knoten.Rechner#maxLayerOfOperation \
+    filius.hardware.knoten.Notebook#maxLayerOfOperation \
+    filius.hardware.knoten.Vermittlungsrechner#maxLayerOfOperation \
+    filius.hardware.knoten.Gateway#maxLayerOfOperation \
+    filius.software.clientserver.ServerBaustein#port \
+    filius.software.dhcp.DHCPServer#port \
+    filius.software.dns.DNSServer#port \
+    filius.software.rip.RIPServer#port \
+    filius.software.www.WebServer#port \
+    2>&1 | grep -v 'logback\|^$' || true
+test -s "$defaults"

tools/java-oracle/src/GetterDefaults.java

@@ -0,0 +1,55 @@
+// Measures the value a JavaBean getter returns on a freshly constructed object.
+// XMLEncoder shares equal Integer and Boolean objects: an int written once as
+// the result of a getter (`<void id="Integer0" property="iconTextGap"/>`) is
+// later referenced by id — e.g. as a node's x coordinate. Decoding such a file
+// needs these defaults; they are measured here, not guessed.
+//
+// Usage: java -cp filius.jar:lib/*:classes GetterDefaults <output json> <fqcn#property>...
+
+import java.beans.Introspector;
+import java.beans.PropertyDescriptor;
+import java.io.FileOutputStream;
+import java.lang.reflect.Method;
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+import java.util.TreeMap;
+
+public class GetterDefaults {
+
+    public static void main(String[] args) throws Exception {
+        Map<String, Object> result = new TreeMap<>();
+        for (int index = 1; index < args.length; index++) {
+            String key = args[index];
+            String className = key.substring(0, key.indexOf('#'));
+            String property = key.substring(key.indexOf('#') + 1);
+            String simpleName = className.substring(className.lastIndexOf('.') + 1);
+            try {
+                Object value = className.equals("java.lang.ThreadGroup")
+                        // A Thread's uncaughtExceptionHandler is its group; XMLDecoder runs
+                        // in the main thread, so that is the group asked.
+                        ? read(Thread.currentThread().getThreadGroup(), property)
+                        : read(Class.forName(className).getDeclaredConstructor().newInstance(), property);
+                result.put(simpleName + "#" + property, value);
+            } catch (Throwable error) {
+                Throwable cause = error.getCause() != null ? error.getCause() : error;
+                result.put(simpleName + "#" + property, Map.of("error", cause.toString()));
+            }
+        }
+        try (FileOutputStream out = new FileOutputStream(args[0])) {
+            out.write((FlsOracle.Json.write(result, "") + "\n").getBytes(StandardCharsets.UTF_8));
+        }
+        System.out.println("getter defaults: " + result.size());
+        System.exit(0);
+    }
+
+    static Object read(Object target, String property) throws Exception {
+        Method getter = null;
+        for (PropertyDescriptor descriptor : Introspector.getBeanInfo(target.getClass()).getPropertyDescriptors()) {
+            if (descriptor.getName().equals(property)) getter = descriptor.getReadMethod();
+        }
+        if (getter == null) getter = target.getClass().getMethod(property);
+        Object value = getter.invoke(target);
+        if (value == null || value instanceof Number || value instanceof Boolean || value instanceof String) return value;
+        return Map.of("class", value.getClass().getName());
+    }
+}