moved withClone and withSelfCopy methods to CopyContext

Author: clausnagel

src/main/java/org/xmlobjects/util/copy/AbstractCloner.java

@@ -40,7 +40,7 @@ final void setCopyBuilder(CopyBuilder builder) {
     @SuppressWarnings("unchecked")
     public final <E> E deepCopy(E value) {
         return value instanceof Copyable copyable ?
-                (E) copyable.deepCopy(builder) :
+                (E) copyable.deepCopy(builder, builder.getContext()) :
                 builder.deepCopy(value);
     }
 

src/main/java/org/xmlobjects/util/copy/CopyBuilder.java

@@ -35,7 +35,6 @@ public class CopyBuilder {
     private static final ThreadLocal<CopyContext> contexts = ThreadLocal.withInitial(CopyContext::new);
     private static final AbstractCloner<Object> IDENTITY_CLONER = new IdentityCloner();
     private static final AbstractCloner<Object> NULL_CLONER = new NullCloner();
-    private static final Object NULL = new Object();
 
     private final Map<Class<?>, AbstractCloner<?>> cloners = new ConcurrentHashMap<>();
     private final Set<Class<?>> immutables = ConcurrentHashMap.newKeySet();
@@ -46,11 +45,6 @@ public class CopyBuilder {
 
     private volatile boolean failOnError;
 
-    private static class CopyContext {
-        private final Map<Object, Object> clones = new IdentityHashMap<>();
-        private boolean isCopying;
-    }
-
     public CopyBuilder() {
         registerKnownCloners();
     }
@@ -102,26 +96,27 @@ public CopyBuilder failOnError(boolean failOnError) {
         return this;
     }
 
+    CopyContext getContext() {
+        return contexts.get();
+    }
+
     @SuppressWarnings("unchecked")
     private <T> T copy(T src, T dest, Class<T> template, boolean shallowCopy) {
         if (src == null || src == dest) {
             return dest;
         }
 
         CopyContext context = contexts.get();
-        boolean isInitial = !context.isCopying;
-        if (isInitial) {
-            context.isCopying = true;
-        }
+        boolean isInitial = context.isInitial();
 
-        T clone = (T) context.clones.get(src);
+        T clone = (T) context.getClone(src);
         try {
             if (clone == null) {
                 if (shallowCopy
                         && isInitial
                         && dest == null
                         && src instanceof Copyable copyable) {
-                    clone = (T) copyable.shallowCopy(this);
+                    clone = (T) copyable.shallowCopy(this, context);
                 } else {
                     if (template == null) {
                         template = (Class<T>) src.getClass();
@@ -131,7 +126,7 @@ private <T> T copy(T src, T dest, Class<T> template, boolean shallowCopy) {
                     if (src instanceof Child child) {
                         Child parent = child.getParent();
                         if (parent != null) {
-                            context.clones.putIfAbsent(parent, parent);
+                            context.addCloneIfAbsent(parent, parent);
                         }
                     }
 
@@ -141,12 +136,12 @@ private <T> T copy(T src, T dest, Class<T> template, boolean shallowCopy) {
                             dest = cloner.newInstance(src, shallowCopy);
                         }
 
-                        context.clones.put(src, dest != null ? dest : NULL);
+                        context.addClone(src, dest);
                     }
 
                     clone = cloner.copy(src, dest, shallowCopy);
                 }
-            } else if (clone == NULL) {
+            } else if (context.isNullClone(clone)) {
                 clone = null;
             }
         } catch (Throwable e) {
@@ -157,8 +152,7 @@ private <T> T copy(T src, T dest, Class<T> template, boolean shallowCopy) {
             }
         } finally {
             if (isInitial) {
-                context.isCopying = false;
-                context.clones.clear();
+                context.clear();
                 contexts.remove();
 
                 // unset parent on initial source object

src/main/java/org/xmlobjects/util/copy/CopyContext.java

@@ -0,0 +1,75 @@
+/*
+ * citygml4j - The Open Source Java API for CityGML
+ * https://github.com/citygml4j
+ *
+ * Copyright 2013-2025 Claus Nagel <claus.nagel@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.xmlobjects.util.copy;
+
+import java.util.IdentityHashMap;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Supplier;
+
+public class CopyContext {
+    private static final Object NULL_CLONE = new Object();
+    private final Map<Object, Object> clones = new IdentityHashMap<>();
+    private final AtomicBoolean initial = new AtomicBoolean(true);
+
+    CopyContext() {
+    }
+
+    boolean isInitial() {
+        return initial.getAndSet(false);
+    }
+
+    Object getClone(Object src) {
+        return clones.get(src);
+    }
+
+    void addClone(Object src, Object dest) {
+        clones.put(src, dest != null ? dest : NULL_CLONE);
+    }
+
+    void addCloneIfAbsent(Object src, Object dest) {
+        clones.putIfAbsent(src, dest != null ? dest : NULL_CLONE);
+    }
+
+    boolean isNullClone(Object src) {
+        return src == null || src == NULL_CLONE;
+    }
+
+    public <T> CopyContext withClone(T src, Supplier<T> supplier) {
+        if (src != null) {
+            addClone(src, supplier.get());
+        }
+
+        return this;
+    }
+
+    public CopyContext withSelfCopy(Object src) {
+        if (src != null) {
+            addClone(src, src);
+        }
+
+        return this;
+    }
+
+    void clear() {
+        clones.clear();
+        initial.set(true);
+    }
+}

src/main/java/org/xmlobjects/util/copy/Copyable.java

@@ -20,11 +20,11 @@
 package org.xmlobjects.util.copy;
 
 public interface Copyable {
-    default Copyable shallowCopy(CopyBuilder builder) {
+    default Copyable shallowCopy(CopyBuilder builder, CopyContext context) {
         return builder.shallowCopy(this);
     }
 
-    default Copyable deepCopy(CopyBuilder builder) {
+    default Copyable deepCopy(CopyBuilder builder, CopyContext context) {
         return builder.deepCopy(this);
     }
 }