From b0b62211d68c1bb5c78335f5e44de5ad621ed4cf Mon Sep 17 00:00:00 2001
From: Tagir Valeev <Tagir.Valeev@jetbrains.com>
Date: Tue, 6 Sep 2016 12:37:05 +0700
Subject: [PATCH] IDEA-160784 Migration to Stream API: replace with
 Stream.count() when possible (now i+=1 and i=i+1 also supported)

---
 .../StreamApiMigrationInspection.java         | 35 +++++++++++++++----
 .../streamApiMigration/beforeCountArray.java  |  2 +-
 .../streamApiMigration/beforeCountOuter.java  |  2 +-
 3 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/StreamApiMigrationInspection.java b/java/java-analysis-impl/src/com/intellij/codeInspection/StreamApiMigrationInspection.java
index f6c71d3c5d8a..c39096d48def 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/StreamApiMigrationInspection.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/StreamApiMigrationInspection.java
@@ -175,18 +175,39 @@ public class StreamApiMigrationInspection extends BaseJavaBatchLocalInspectionTo
     };
   }
 
+  private static boolean isLiteral(PsiElement element, Object value) {
+    return element instanceof PsiLiteralExpression && value.equals(((PsiLiteralExpression)element).getValue());
+  }
+
   private static PsiExpression extractIncrementedExpression(PsiStatement statement) {
     if(!(statement instanceof PsiExpressionStatement)) return null;
     PsiExpression expression = ((PsiExpressionStatement)statement).getExpression();
-    PsiExpression operand;
     if(expression instanceof PsiPostfixExpression) {
-      if(!JavaTokenType.PLUSPLUS.equals(((PsiPostfixExpression)expression).getOperationTokenType())) return null;
-      operand = ((PsiPostfixExpression)expression).getOperand();
+      if(JavaTokenType.PLUSPLUS.equals(((PsiPostfixExpression)expression).getOperationTokenType())) {
+        return ((PsiPostfixExpression)expression).getOperand();
+      }
     } else if(expression instanceof PsiPrefixExpression) {
-      if(!JavaTokenType.PLUSPLUS.equals(((PsiPrefixExpression)expression).getOperationTokenType())) return null;
-      operand = ((PsiPrefixExpression)expression).getOperand();
-    } else return null; // TODO: support i = i+1;
-    return operand;
+      if(JavaTokenType.PLUSPLUS.equals(((PsiPrefixExpression)expression).getOperationTokenType())) {
+        return ((PsiPrefixExpression)expression).getOperand();
+      }
+    } else if(expression instanceof PsiAssignmentExpression) {
+      PsiAssignmentExpression assignment = (PsiAssignmentExpression)expression;
+      if(JavaTokenType.PLUSEQ.equals(assignment.getOperationTokenType())) {
+        if (isLiteral(assignment.getRExpression(), 1)) {
+          return assignment.getLExpression();
+        }
+      } else if(JavaTokenType.EQ.equals(assignment.getOperationTokenType())) {
+        if (assignment.getRExpression() instanceof PsiBinaryExpression) {
+          PsiBinaryExpression binOp = (PsiBinaryExpression)assignment.getRExpression();
+          if(JavaTokenType.PLUS.equals(binOp.getOperationTokenType()) && binOp.getROperand() != null && (
+            isLiteral(binOp.getROperand(), 1) && binOp.getLOperand().getText().equals(assignment.getLExpression().getText()) ||
+            isLiteral(binOp.getLOperand(), 1) && binOp.getROperand().getText().equals(assignment.getLExpression().getText()))) {
+            return assignment.getLExpression();
+          }
+        }
+      }
+    }
+    return null;
   }
 
   @Nullable
diff --git a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeCountArray.java b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeCountArray.java
index 5d1ed4169250..15a2f4097260 100644
--- a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeCountArray.java
+++ b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeCountArray.java
@@ -6,7 +6,7 @@ public class Main {
     for(String str : a<caret>rray) {
       String trimmed = str.trim();
       if(trimmed.length() > 10) {
-        longStrings++;
+        longStrings = longStrings + 1;
       }
     }
     return longStrings;
diff --git a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeCountOuter.java b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeCountOuter.java
index 4da30a7d6f1f..aaf4234b74e7 100644
--- a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeCountOuter.java
+++ b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeCountOuter.java
@@ -9,7 +9,7 @@ public class Main {
       if(element != null) {
         for(String str : element) {
           if(str.startsWith("xyz")) {
-            count++;
+            ++count;
           }
         }
       }