Parse ClassOrInterfaceType recursively

pmd-java/etc/grammar/Java.jjt

@@ -214,6 +214,8 @@ import java.util.List;
 import java.util.Map;
 import net.sourceforge.pmd.lang.ast.CharStream;
 import net.sourceforge.pmd.lang.ast.TokenMgrError;
+import net.sourceforge.pmd.lang.ast.Node;
+
 public class JavaParser {
 
   private int jdkVersion = 0;
@@ -1987,18 +1989,51 @@ void ReferenceType() #void:
   | ( ClassOrInterfaceType() [ LOOKAHEAD(2) Dims() ] )   #ArrayType(>1)
 }
 
-void ClassOrInterfaceType():
+void ClassOrInterfaceType() #void:
 {
   StringBuilder s = new StringBuilder();
   Token t;
 }
 {
-  t=<IDENTIFIER> {s.append(t.image);}
-  [ LOOKAHEAD(2) TypeArguments() ]
-  ( LOOKAHEAD(2) "." t=<IDENTIFIER> {s.append('.').append(t.image);} [ LOOKAHEAD(2) TypeArguments() ] )*
-  {jjtThis.setImage(s.toString());}
+  (
+    (
+      t=<IDENTIFIER> { s.append(t.getImage()); }
+      // We gobble up all identifiers until we find
+      // either type arguments or annotations, because
+      // it may be a FQCN
+      ( LOOKAHEAD("." <IDENTIFIER>)
+        "." t=<IDENTIFIER> { s.append('.').append(t.getImage()); }
+      )*
+    )
+    [ LOOKAHEAD( "<" ) TypeArguments() ]
+  ) #ClassOrInterfaceType
+  {
+    // At this point the first ClassOrInterfaceType is on top of the stack
+    jjtree.peekNode().setImage(s.toString());
   }
 
+
+  ( LOOKAHEAD(2)
+      (
+        "."
+        (TypeAnnotation())*
+        t=<IDENTIFIER> { jjtThis.setImage(t.getImage()); }
+        [ LOOKAHEAD( "<" ) TypeArguments() ]
+      ) #ClassOrInterfaceType {
+        // At this point the newer ClassOrInterfaceType has been pushed on the stack
+        // We retrieve it
+        AbstractJavaNode lastSegment = (AbstractJavaNode) jjtree.popNode();
+        // All its children (annotations and type arguments) have already been popped,
+        // so the node remaining on top of the stack is the previous segment
+        Node previousSegment = jjtree.popNode();
+
+        lastSegment.insertChild((JavaNode) previousSegment, 0, true);
+        jjtree.pushNode(lastSegment);
+      }
+  )*
+}
+
+
 void TypeArguments():
 {}
 {

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/ASTClassOrInterfaceType.java

@@ -5,15 +5,34 @@
 
 package net.sourceforge.pmd.lang.java.ast;
 
+import java.util.Optional;
+
+// @formatter:off
 /**
  * Represents a class or interface type, possibly parameterised with type arguments.
+ * This node comes in two productions (see below):
+ *
+ * <p>The first is a left-recursive variant, allowing to parse references to type members
+ * unambiguously. The resulting node's {@linkplain #getLeftHandSide() left-hand-side type}
+ * addresses the type parent of the type. The position of type arguments and annotations are
+ * preserved.
+ *
+ * <p>Parsing types left-recursively has a caveat though: fully-qualified type names. The
+ * parser can't disambiguate between a reference to a type member (e.g. {@code Map.Entry}, where
+ * both segments refer to a type, and which would ideally be parsed left-recursively), and a
+ * qualified type name (e.g. {@code java.util.List}, where the full sequence refers to a unique
+ * type, but individual segments don't).
+ *
+ * <p>We could remove that with a later AST visit, like type resolution though!
  *
  * <pre>
  *
- * ClassOrInterfaceType ::= &lt;IDENTIFIER&gt; {@linkplain ASTTypeArguments TypeArguments}? ( "." &lt;IDENTIFIER&gt;  {@linkplain ASTTypeArguments TypeArguments}? )*
+ * ClassOrInterfaceType ::= ClassOrInterfaceType ( "." {@linkplain ASTAnnotation Annotation}* &lt;IDENTIFIER&gt; {@linkplain ASTTypeArguments TypeArguments}? )+
+ *                        | &lt;IDENTIFIER&gt; ( "." &lt;IDENTIFIER&gt; ) *  {@linkplain ASTTypeArguments TypeArguments}?
  *
  * </pre>
  */
+// @formatter:on
 public class ASTClassOrInterfaceType extends AbstractJavaTypeNode implements ASTReferenceType {
     public ASTClassOrInterfaceType(String identifier) {
         super(JavaParserTreeConstants.JJTCLASSORINTERFACETYPE);
@@ -31,6 +50,17 @@ public class ASTClassOrInterfaceType extends AbstractJavaTypeNode implements AST
     }
 
 
+    /**
+     * Gets the left-hand side type of this type. This is a type we know for sure
+     * that this type is a member of.
+     *
+     * @return A type, or null if this is a base type
+     */
+    public Optional<ASTClassOrInterfaceType> getLeftHandSide() {
+        return Optional.ofNullable(getFirstChildOfType(ASTClassOrInterfaceType.class));
+    }
+
+
     @Override
     public Object jjtAccept(JavaParserVisitor visitor, Object data) {
         return visitor.visit(this, data);
@@ -48,8 +78,8 @@ public class ASTClassOrInterfaceType extends AbstractJavaTypeNode implements AST
      * same compilation unit - either a class/interface or a enum type. You want
      * to check this, if {@link #getType()} is null.
      *
-     * @return <code>true</code> if this node referencing a type in the same
-     * compilation unit, <code>false</code> otherwise.
+     * @return {@code true} if this node referencing a type in the same
+     * compilation unit, {@code false} otherwise.
      */
     public boolean isReferenceToClassSameCompilationUnit() {
         ASTCompilationUnit root = getFirstParentOfType(ASTCompilationUnit.class);

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/AbstractJavaNode.java

@@ -8,21 +8,25 @@ import net.sourceforge.pmd.lang.ast.AbstractNode;
 import net.sourceforge.pmd.lang.ast.Node;
 import net.sourceforge.pmd.lang.symboltable.Scope;
 
+
 public abstract class AbstractJavaNode extends AbstractNode implements JavaNode {
 
     protected JavaParser parser;
     private Scope scope;
     private Comment comment;
 
+
     public AbstractJavaNode(int id) {
         super(id);
     }
 
+
     public AbstractJavaNode(JavaParser parser, int id) {
         super(id);
         this.parser = parser;
     }
 
+
     @Override
     public void jjtOpen() {
         if (beginLine == -1 && parser.token.next != null) {
@@ -31,6 +35,7 @@ public abstract class AbstractJavaNode extends AbstractNode implements JavaNode
         }
     }
 
+
     @Override
     public void jjtClose() {
         if (beginLine == -1 && children.length == 0) {
@@ -43,6 +48,7 @@ public abstract class AbstractJavaNode extends AbstractNode implements JavaNode
         endColumn = parser.token.endColumn;
     }
 
+
     /**
      * Accept the visitor. *
      */
@@ -88,20 +94,70 @@ public abstract class AbstractJavaNode extends AbstractNode implements JavaNode
         return scope;
     }
 
+
     @Override
     public void setScope(Scope scope) {
         this.scope = scope;
     }
 
+
     public void comment(Comment theComment) {
         comment = theComment;
     }
 
+
     public Comment comment() {
         return comment;
     }
 
 
+    // insert a child at a given index, shifting other children if need be
+    // The implementation of jjtAddChild in AbstractNode overwrites nodes
+    // -> probably unexpected and to be changed
+    // parser only
+    void insertChild(JavaNode child, int index, boolean expandTextSpan) {
+        // Allow to insert a child at random index without overwriting
+        // If the child is null, it is replaced. If it is not null, children are shifted
+        if (children != null && index < children.length && children[index] != null) {
+            Node[] newChildren = new Node[children.length + 1];
+
+            // toShift nodes are to the right of the insertion index
+            int toShift = children.length - index;
+
+            // copy the nodes before
+            System.arraycopy(children, 0, newChildren, 0, index);
+
+            // copy the nodes after
+            System.arraycopy(children, index, newChildren, index + 1, toShift);
+            children = newChildren;
+        }
+        super.jjtAddChild(child, index);
+        child.jjtSetParent(this);
+
+        // The text coordinates of this node will be enlarged with those of the child 
+        if (expandTextSpan) {
+            AbstractJavaNode childImpl = (AbstractJavaNode) child;
+
+            if (this.beginLine > childImpl.beginLine) {
+                this.beginLine = childImpl.beginLine;
+                this.beginColumn = childImpl.beginColumn;
+            } else if (this.beginLine == childImpl.beginLine
+                    && this.beginColumn > childImpl.beginColumn) {
+                this.beginColumn = childImpl.beginColumn;
+            }
+
+            if (this.endLine < childImpl.endLine) {
+                this.endLine = childImpl.endLine;
+                this.endColumn = childImpl.endColumn;
+            } else if (this.endLine == childImpl.endLine
+                    && this.endColumn < childImpl.endColumn) {
+                this.endColumn = childImpl.endColumn;
+            }
+
+            // TODO tokens
+        }
+    }
+
 
     @Override
     public final String getXPathNodeName() {