Refactor ClassSignature to calculate isNonPortableRuntime upfront on …

…instantiation

src/main/java/de/thetaphi/forbiddenapis/ClassScanner.java

@@ -99,7 +99,7 @@ String checkClassUse(Type type, String what, boolean deep, String origInternalNa
     if (deep && forbidNonPortableRuntime) {
       final String binaryClassName = type.getClassName();
       final ClassSignature c = lookup.lookupRelatedClass(type.getInternalName(), origInternalName);
-      if (c != null && c.isRuntimeClass && !AsmUtils.isPortableRuntimeClass(binaryClassName)) {
+      if (c != null && c.isNonPortableRuntime) {
         return String.format(Locale.ENGLISH,
           "Forbidden %s use: %s [non-portable or internal runtime class]",
           what, binaryClassName

src/main/java/de/thetaphi/forbiddenapis/ClassSignature.java

@@ -36,7 +36,7 @@
 final class ClassSignature implements Constants {
   private ClassReader reader;
 
-  public final boolean isRuntimeClass;
+  public final boolean isRuntimeClass, isNonPortableRuntime;
   public final Set<Method> methods;
   public final Set<String> fields, signaturePolymorphicMethods;
   public final String className, superName;
@@ -76,6 +76,7 @@ public FieldVisitor visitField(int access, String name, String desc, String sign
     this.methods = createSet(methods);
     this.fields = createSet(fields);
     this.signaturePolymorphicMethods = createSet(signaturePolymorphicMethods);
+    this.isNonPortableRuntime = this.determineNonPortableRuntime();
   }
 
   /** Alternative ctor that can be used to build the information via reflection from an already loaded class. Useful for Java 9 Jigsaw. */
@@ -112,19 +113,28 @@ public ClassSignature(final Class<?> clazz, boolean isRuntimeClass) {
     this.methods = createSet(methods);
     this.fields = createSet(fields);
     this.signaturePolymorphicMethods = createSet(signaturePolymorphicMethods);
+    this.isNonPortableRuntime = this.determineNonPortableRuntime();
   }
 
   private static <T> Set<T> createSet(Set<? extends T> s) {
     return s.isEmpty() ? Collections.<T>emptySet() : Collections.<T>unmodifiableSet(s);
   }
+
+  private boolean determineNonPortableRuntime() {
+    return isRuntimeClass && !AsmUtils.isPortableRuntimeClass(getBinaryClassName());
+  }
 
   public ClassReader getReader() {
     if (reader == null)
-      throw new IllegalStateException("'" + Type.getObjectType(className).getClassName() + "' has no ClassReader, because it was already checked or is only loaded as related class.");
+      throw new IllegalStateException("'" + getBinaryClassName() + "' has no ClassReader, because it was already checked or is only loaded as related class.");
     try {
       return reader;
     } finally {
       reader = null;
     }
   }
+
+  public String getBinaryClassName() {
+    return Type.getObjectType(className).getClassName();
+  }
 }