1 files changed, 74 insertions, 0 deletions
diff --git a/javaparser-core/src/main/java/com/github/javaparser/printer/lexicalpreservation/PhantomNodeLogic.java b/javaparser-core/src/main/java/com/github/javaparser/printer/lexicalpreservation/PhantomNodeLogic.java
new file mode 100644
index 000000000..d17f76835
--- /dev/null
+++ b/javaparser-core/src/main/java/com/github/javaparser/printer/lexicalpreservation/PhantomNodeLogic.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2007-2010 Júlio Vilmar Gesser.
+ * Copyright (C) 2011, 2013-2016 The JavaParser Team.
+ *
+ * This file is part of JavaParser.
+ *
+ * JavaParser can be used either under the terms of
+ * a) the GNU Lesser General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ * b) the terms of the Apache License
+ *
+ * You should have received a copy of both licenses in LICENCE.LGPL and
+ * LICENCE.APACHE. Please refer to those files for details.
+ *
+ * JavaParser is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ */
+
+package com.github.javaparser.printer.lexicalpreservation;
+
+import com.github.javaparser.ast.Node;
+import com.github.javaparser.ast.observer.AstObserver;
+import com.github.javaparser.ast.observer.AstObserverAdapter;
+import com.github.javaparser.ast.type.UnknownType;
+
+import java.util.IdentityHashMap;
+import java.util.Map;
+
+import static java.util.Collections.synchronizedMap;
+
+/**
+ * We want to recognize and ignore "phantom" nodes, like the fake type of variable in FieldDeclaration
+ */
+class PhantomNodeLogic {
+
+    private static final int LEVELS_TO_EXPLORE = 3;
+
+    private static final Map<Node, Boolean> isPhantomNodeCache = synchronizedMap(new IdentityHashMap<>());
+
+    private static final AstObserver cacheCleaner = new AstObserverAdapter() {
+        @Override
+        public void parentChange(Node observedNode, Node previousParent, Node newParent) {
+            isPhantomNodeCache.remove(observedNode);
+        }
+    };
+
+    static boolean isPhantomNode(Node node) {
+        if (isPhantomNodeCache.containsKey(node)) {
+            return isPhantomNodeCache.get(node);
+        } else {
+            if (node instanceof UnknownType) {
+                return true;
+            }
+            boolean res = (node.getParentNode().isPresent() &&
+                    !node.getParentNode().get().getRange().get().contains(node.getRange().get())
+                    || inPhantomNode(node, LEVELS_TO_EXPLORE));
+            isPhantomNodeCache.put(node, res);
+            node.register(cacheCleaner);
+            return res;
+        }
+    }
+
+    /**
+     * A node contained in a phantom node is also a phantom node. We limit how many levels up we check just for performance reasons.
+     */
+    private static boolean inPhantomNode(Node node, int levels) {
+        return node.getParentNode().isPresent() &&
+                (isPhantomNode(node.getParentNode().get())
+                        || inPhantomNode(node.getParentNode().get(), levels - 1));
+    }
+}