[DROOLS-7253] Review and improve drools-lsp parser Visitor design (ap…

…ache#16) * [DROOLS-7253] Review and improve drools-lsp parser Visitor design - Remove currentConstructStack. Utilize return object instead. * - Remove instance fields. Utilize return objects instead.
tkobayas · Feb 15, 2024 · fed7278 · fed7278
1 parent 9ef91f4
commit fed7278
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Showing 4 changed files with 245 additions and 161 deletions.
diff --git a/drools-drl/drools-drl10-parser/src/main/java/org/drools/parser/DRLParserException.java b/drools-drl/drools-drl10-parser/src/main/java/org/drools/parser/DRLParserException.java
@@ -0,0 +1,12 @@
+package org.drools.parser;
+
+public class DRLParserException extends RuntimeException {
+
+    public DRLParserException() {
+        super();
+    }
+
+    public DRLParserException(String message) {
+        super(message);
+    }
+}
diff --git a/drools-drl/drools-drl10-parser/src/main/java/org/drools/parser/DRLParserHelper.java b/drools-drl/drools-drl10-parser/src/main/java/org/drools/parser/DRLParserHelper.java
@@ -3,7 +3,6 @@
 import org.antlr.v4.runtime.CharStream;
 import org.antlr.v4.runtime.CharStreams;
 import org.antlr.v4.runtime.CommonTokenStream;
-import org.antlr.v4.runtime.RuleContext;
 import org.antlr.v4.runtime.Token;
 import org.antlr.v4.runtime.tree.ErrorNode;
 import org.antlr.v4.runtime.tree.ParseTree;
@@ -12,40 +11,46 @@
 
 public class DRLParserHelper {
 
+    private DRLParserHelper() {
+    }
+
     public static PackageDescr parse(String drl) {
-        return parseTree2PackageDescr(createParseTree(drl));
+        return compilationUnitContext2PackageDescr(createParseTree(drl));
     }
 
-    public static ParseTree createParseTree(String drl) {
+    public static DRLParser.CompilationUnitContext createParseTree(String drl) {
         return createDrlParser(drl).compilationUnit();
     }
 
     public static DRLParser createDrlParser(String drl) {
         CharStream inputStream = CharStreams.fromString(drl);
         DRLLexer drlLexer = new DRLLexer(inputStream);
         CommonTokenStream commonTokenStream = new CommonTokenStream(drlLexer);
-        DRLParser drlParser = new DRLParser(commonTokenStream);
-        return drlParser;
+        return new DRLParser(commonTokenStream);
     }
 
-    public static PackageDescr parseTree2PackageDescr(ParseTree parseTree) {
+    public static PackageDescr compilationUnitContext2PackageDescr(DRLParser.CompilationUnitContext ctx) {
         DRLVisitorImpl visitor = new DRLVisitorImpl();
-        visitor.visit(parseTree);
-        return visitor.getPackageDescr();
+        Object descr = visitor.visit(ctx);
+        if (descr instanceof PackageDescr) {
+            return (PackageDescr) descr;
+        } else {
+            throw new DRLParserException("CompilationUnitContext should produce PackageDescr. descr = " + descr.getClass());
+        }
     }
 
-
     public static Integer computeTokenIndex(DRLParser parser, int row, int col) {
         for (int i = 0; i < parser.getInputStream().size(); i++) {
             Token token = parser.getInputStream().get(i);
             int start = token.getCharPositionInLine();
             int stop = token.getCharPositionInLine() + token.getText().length();
-            if (token.getLine() > row)
+            if (token.getLine() > row) {
                 return token.getTokenIndex() - 1;
-            else if (token.getLine() == row && start >= col)
+            } else if (token.getLine() == row && start >= col) {
                 return token.getTokenIndex() == 0 ? 0 : token.getTokenIndex() - 1;
-            else if (token.getLine() == row && start < col && stop >= col)
+            } else if (token.getLine() == row && start < col && stop >= col) {
                 return token.getTokenIndex();
+            }
         }
         return null;
     }

diff --git a/drools-drl/drools-drl10-parser/src/main/java/org/drools/parser/DRLParserWrapper.java b/drools-drl/drools-drl10-parser/src/main/java/org/drools/parser/DRLParserWrapper.java
@@ -4,31 +4,29 @@
 import java.util.List;
 import java.util.stream.Collectors;
 
-import org.antlr.v4.runtime.tree.ParseTree;
 import org.drools.drl.ast.descr.PackageDescr;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import static org.drools.parser.DRLParserHelper.compilationUnitContext2PackageDescr;
+
 public class DRLParserWrapper {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(DRLParserWrapper.class);
 
     private final List<DRLParserError> errors = new ArrayList<>();
 
-    public DRLParserWrapper() {
-    }
-
     public PackageDescr parse(String drl) {
         DRLParser drlParser = DRLParserHelper.createDrlParser(drl);
         DRLErrorListener errorListener = new DRLErrorListener();
         drlParser.addErrorListener(errorListener);
 
-        ParseTree parseTree = drlParser.compilationUnit();
+        DRLParser.CompilationUnitContext cxt = drlParser.compilationUnit();
 
         errors.addAll(errorListener.getErrors());
 
         try {
-            return DRLParserHelper.parseTree2PackageDescr(parseTree);
+            return compilationUnitContext2PackageDescr(cxt);
         } catch (Exception e) {
             LOGGER.error("Exception while creating PackageDescr", e);
             errors.add(new DRLParserError(e));