Issue checkstyle#12809: Improve performance of lambda processing

nrmancuso · Mar 10, 2023 · 229e827 · 229e827
1 parent 0cba05e
commit 229e827
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Showing 2 changed files with 6 additions and 21 deletions.
diff --git a/src/main/java/com/puppycrawl/tools/checkstyle/JavaAstVisitor.java b/src/main/java/com/puppycrawl/tools/checkstyle/JavaAstVisitor.java
@@ -1495,7 +1495,11 @@ public DetailAstImpl visitSimpleMethodCall(JavaLanguageParser.SimpleMethodCallCo
 
     @Override
     public DetailAstImpl visitLambdaExp(JavaLanguageParser.LambdaExpContext ctx) {
-        return flattenedTree(ctx);
+        final DetailAstImpl lambda = create(ctx.LAMBDA());
+        processChildren(lambda, ctx.children.stream()
+                .filter(child -> !child.equals(ctx.LAMBDA()))
+                .collect(Collectors.toList()));
+        return lambda;
     }
 
     @Override
@@ -1627,14 +1631,6 @@ public DetailAstImpl visitTypeCastParameters(
         return typeType;
     }
 
-    @Override
-    public DetailAstImpl visitLambdaExpression(JavaLanguageParser.LambdaExpressionContext ctx) {
-        final DetailAstImpl lambda = create(ctx.LAMBDA());
-        lambda.addChild(visit(ctx.lambdaParameters()));
-        lambda.addChild(visit(ctx.lambdaBody()));
-        return lambda;
-    }
-
     @Override
     public DetailAstImpl visitSingleLambdaParam(JavaLanguageParser.SingleLambdaParamContext ctx) {
         return flattenedTree(ctx);

diff --git a/src/main/resources/com/puppycrawl/tools/checkstyle/grammar/java/JavaLanguageParser.g4 b/src/main/resources/com/puppycrawl/tools/checkstyle/grammar/java/JavaLanguageParser.g4
@@ -720,18 +720,13 @@ expr
         | BAND_ASSIGN | BOR_ASSIGN | BXOR_ASSIGN | SR_ASSIGN | BSR_ASSIGN
         | SL_ASSIGN | MOD_ASSIGN)
       expr                                                                 #binOp
-    | lambdaExpression                                                     #lambdaExp
+    | lambdaParameters LAMBDA (expression | block)                         #lambdaExp
     ;
 
 typeCastParameters
     : typeType[true] (BAND typeType[true])*
     ;
 
-// Java8
-lambdaExpression
-    : lambdaParameters LAMBDA lambdaBody
-    ;
-
 // Java8
 lambdaParameters
     : id                                                                   #singleLambdaParam
@@ -743,12 +738,6 @@ multiLambdaParams
     : id (COMMA id)*
     ;
 
-// Java8
-lambdaBody
-    : expression
-    | block
-    ;
-
 primary
     : switchExpressionOrStatement                                          #switchPrimary
     | LPAREN expr RPAREN                                                   #parenPrimary