Refactoring adding convenient methods to know if a DifferenceElement is added, removed or kept

javaparser-core/src/main/java/com/github/javaparser/printer/lexicalpreservation/Added.java

@@ -67,6 +67,11 @@ public boolean isAdded() {
     public boolean isRemoved() {
         return false;
     }
+
+    @Override
+    public boolean isKept() {
+        return false;
+    }
 
     public boolean isIndent() { return element instanceof CsmIndent; }
 

javaparser-core/src/main/java/com/github/javaparser/printer/lexicalpreservation/Difference.java

@@ -179,16 +179,16 @@ void apply() {
             if (!isLeftOverDiffElement && !isLeftOverOriginalElement){
                 DifferenceElement diffElement = diffElements.get(diffIndex);
 
-                if (diffElement instanceof Added) {
+                if (diffElement.isAdded()) {
                     applyAddedDiffElement((Added) diffElement);
                 } else {
                     TextElement originalElement = originalElements.get(originalIndex);
                     boolean originalElementIsChild = originalElement instanceof ChildTextElement;
                     boolean originalElementIsToken = originalElement instanceof TokenTextElement;
 
-                    if (diffElement instanceof Kept) {
+                    if (diffElement.isKept()) {
                         applyKeptDiffElement((Kept) diffElement, originalElement, originalElementIsChild, originalElementIsToken);
-                    } else if (diffElement instanceof Removed) {
+                    } else if (diffElement.isRemoved()) {
                         Removed removed = (Removed) diffElement;
                         applyRemovedDiffElement(removedGroups.get(removed), removed, originalElement, originalElementIsChild, originalElementIsToken);
                     } else {
@@ -220,9 +220,9 @@ private boolean applyLeftOverDiffElements() {
         boolean isLeftOverElement = false;
         if (diffIndex < diffElements.size() && originalIndex >= originalElements.size()) {
             DifferenceElement diffElement = diffElements.get(diffIndex);
-            if (diffElement instanceof Kept) {
+            if (diffElement.isKept()) {
                 diffIndex++;
-            } else if (diffElement instanceof Added) {
+            } else if (diffElement.isAdded()) {
                 Added addedElement = (Added) diffElement;
 
                 nodeText.addElement(originalIndex, addedElement.toTextElement());
@@ -372,7 +372,7 @@ private Map<Integer, List<Removed>> groupConsecutiveRemovedElements() {
         Integer firstElement = null;
         for (int i = 0; i < diffElements.size(); i++) {
             DifferenceElement diffElement = diffElements.get(i);
-            if (diffElement instanceof Removed) {
+            if (diffElement.isRemoved()) {
                 if (firstElement == null) {
                     firstElement = i;
                 }
@@ -401,7 +401,7 @@ private void applyRemovedDiffElement(RemovedGroup removedGroup, Removed removed,
             } else {
                 nodeText.removeElement(originalIndex);
 
-                if ((diffIndex + 1 >= diffElements.size() || !(diffElements.get(diffIndex + 1) instanceof Added))
+                if ((diffIndex + 1 >= diffElements.size() || !(diffElements.get(diffIndex + 1).isAdded()))
                         && !removedGroup.isACompleteLine()) {
                     originalIndex = considerEnforcingIndentation(nodeText, originalIndex);
                 }
@@ -410,7 +410,7 @@ private void applyRemovedDiffElement(RemovedGroup removedGroup, Removed removed,
                     if (originalElements.get(originalIndex).isWhiteSpace()
                             && originalElements.get(originalIndex - 1).isWhiteSpace()) {
                         // However we do not want to do that when we are about to adding or removing elements
-                        if ((diffIndex + 1) == diffElements.size() || (diffElements.get(diffIndex + 1) instanceof Kept)) {
+                        if ((diffIndex + 1) == diffElements.size() || (diffElements.get(diffIndex + 1).isKept())) {
                             originalElements.remove(originalIndex--);
                         }
                     }
@@ -1055,14 +1055,14 @@ private int adjustIndentation(List<TokenTextElement> indentation, NodeText nodeT
      * Returns true if the current <code>Added</code> element is preceded by a <code>Removed</code> element.
      */
     private boolean isAReplacement(int diffIndex) {
-        return (diffIndex > 0) && diffElements.get(diffIndex) instanceof Added && diffElements.get(diffIndex - 1) instanceof Removed;
+        return (diffIndex > 0) && diffElements.get(diffIndex).isAdded() && diffElements.get(diffIndex - 1).isRemoved();
     }
 
     /*
      * Returns true if the current <code>Removed</code> element is followed by a <code>Added</code> element.
      */
     private boolean isReplaced(int diffIndex) {
-        return (diffIndex < diffElements.size() - 1) && diffElements.get(diffIndex + 1) instanceof Added && diffElements.get(diffIndex) instanceof Removed;
+        return (diffIndex < diffElements.size() - 1) && diffElements.get(diffIndex + 1).isAdded() && diffElements.get(diffIndex).isRemoved();
     }
 
     @Override

javaparser-core/src/main/java/com/github/javaparser/printer/lexicalpreservation/DifferenceElement.java

@@ -45,6 +45,8 @@ static DifferenceElement kept(CsmElement element) {
 
     boolean isRemoved();
 
+    boolean isKept();
+
     default boolean isChild() { 
         return getElement() instanceof LexicalDifferenceCalculator.CsmChild; 
     }

javaparser-core/src/main/java/com/github/javaparser/printer/lexicalpreservation/Kept.java

@@ -73,6 +73,16 @@ public int getTokenType() {
     public boolean isAdded() {
         return false;
     }
+
+    @Override
+    public boolean isRemoved() {
+        return false;
+    }
+
+    @Override
+    public boolean isKept() {
+        return true;
+    }
 
     public boolean isIndent() { return element instanceof CsmIndent; }
 
@@ -116,8 +126,4 @@ public boolean isNewLine() {
         return false;
     }
 
-    @Override
-    public boolean isRemoved() {
-        return false;
-    }
 }

javaparser-core/src/main/java/com/github/javaparser/printer/lexicalpreservation/Removed.java

@@ -80,6 +80,16 @@ public int getTokenType() {
     public boolean isAdded() {
         return false;
     }
+
+    @Override
+    public boolean isRemoved() {
+        return true;
+    }
+
+    @Override
+    public boolean isKept() {
+        return false;
+    }
 
     public boolean isToken() { return element instanceof CsmToken; }
 
@@ -101,11 +111,6 @@ public boolean isWhiteSpace() {
         return false;
     }
 
-    @Override
-    public boolean isRemoved() {
-        return true;
-    }
-
     public boolean isNewLine() {
         if(isToken()) {
             CsmToken csmToken = (CsmToken) element;

javaparser-core/src/main/java/com/github/javaparser/printer/lexicalpreservation/Reshuffled.java

@@ -87,6 +87,11 @@ public boolean isRemoved() {
         return false;
     }
 
+    @Override
+    public boolean isKept() {
+        return false;
+    }
+
     /*
      * If the {@code DifferenceElement} wraps an EOL token then this method returns a new {@code DifferenceElement}
      * with all eof token replaced by the specified line separator. The line separator parameter must be a CsmToken with a valid line separator.