introduce functional: convert to lambda when applicable (IDEA-174018)

java/java-impl/src/com/intellij/refactoring/introduceVariable/IntroduceFunctionalVariableHandler.java

@@ -17,6 +17,7 @@ package com.intellij.refactoring.introduceVariable;
 
 import com.intellij.codeInsight.FunctionalInterfaceSuggester;
 import com.intellij.codeInsight.navigation.NavigationUtil;
+import com.intellij.codeInspection.AnonymousCanBeLambdaInspection;
 import com.intellij.ide.util.PsiClassListCellRenderer;
 import com.intellij.openapi.actionSystem.DataContext;
 import com.intellij.openapi.application.ApplicationManager;
@@ -159,9 +160,20 @@ public class IntroduceFunctionalVariableHandler extends IntroduceVariableHandler
       }
     }
     final PsiMethodCallExpression methodCall = processor.getMethodCall();
-    PsiExpression psiExpression = factory
+    PsiMethodCallExpression psiExpression = (PsiMethodCallExpression)factory
       .createExpressionFromText("new " + selectedType.getCanonicalText() + "() {" + extractedMethod.getText() + "}." + methodCall.getText(),
                                 methodCall);
+    PsiExpression qualifierExpression = psiExpression.getMethodExpression().getQualifierExpression();
+    assert qualifierExpression != null;
+    if (AnonymousCanBeLambdaInspection.canBeConvertedToLambda(((PsiNewExpression)qualifierExpression).getAnonymousClass(), false, Collections.emptySet())) {
+      PsiExpression castExpression = JavaPsiFacade.getElementFactory(project)
+        .createExpressionFromText("((" +
+                                  selectedType.getCanonicalText() + ")" +
+                                  AnonymousCanBeLambdaInspection.replaceAnonymousWithLambda(qualifierExpression, selectedType).getText() +
+                                  ")", qualifierExpression);
+      qualifierExpression.replace(castExpression);
+    }
+      
     processor.getExtractedMethod().delete();
     return (PsiMethodCallExpression)JavaCodeStyleManager.getInstance(project).shortenClassReferences(methodCall.replace(psiExpression));
   }

java/java-tests/testData/refactoring/introduceFunctionalVariable/afterExpressionInLoopNoVars.java

@@ -3,12 +3,8 @@ import java.util.function.Supplier;
 class Test {
     void foo() {
     if (true) {
-        Supplier<String> supplier = new Supplier<String>() {
-            public String get() {
-                return "Hello, world";
-            }
-        };
-        System.out.println(supplier.get());
+        Supplier<String> stringSupplier = () -> "Hello, world";
+        System.out.println(stringSupplier.get());
     }
   }
 }

java/java-tests/testData/refactoring/introduceFunctionalVariable/afterExpressionNoVarsSelected.java

@@ -2,11 +2,7 @@ import java.util.function.Supplier;
 
 class Test {
     void foo() {
-        Supplier<String> supplier = new Supplier<String>() {
-            public String get() {
-                return "Hello, world";
-            }
-        };
-        System.out.println(supplier.get());
+        Supplier<String> stringSupplier = () -> "Hello, world";
+        System.out.println(stringSupplier.get());
   }
 }

java/java-tests/testData/refactoring/introduceFunctionalVariable/afterPassFieldsAsParameters.java

@@ -4,12 +4,8 @@ class Test {
     String myName;
   void foo() {
     if (true) {
-        Consumer<String> consumer = new Consumer<String>() {
-            public void accept(String myName) {
-                System.out.println("Hello, world " + myName);
-            }
-        };
-        consumer.accept(myName);
+        Consumer<String> stringConsumer = myName -> System.out.println("Hello, world " + myName);
+        stringConsumer.accept(myName);
     }
   }
 }

java/java-tests/testData/refactoring/introduceFunctionalVariable/afterSkipUsedLocals.java

@@ -1,11 +1,7 @@
 class Test {
     void foo(String name) {
         System.out.println("Hello, ");
-        Runnable runnable = new Runnable() {
-            public void run() {
-                System.out.println(name);
-            }
-        };
+        Runnable runnable = () -> System.out.println(name);
         runnable.run();
     }
 }

java/java-tests/testData/refactoring/introduceFunctionalVariable/afterStatementInLoop.java

@@ -3,12 +3,8 @@ import java.util.function.Consumer;
 class Test {
     void foo(String s) {
     if (true) {
-        Consumer<String> consumer = new Consumer<String>() {
-            public void accept(String s) {
-                System.out.println("Hello, world " + s);
-            }
-        };
-        consumer.accept(s);
+        Consumer<String> stringConsumer = s1 -> System.out.println("Hello, world " + s1);
+        stringConsumer.accept(s);
     }
     }
 }

java/java-tests/testData/refactoring/introduceFunctionalVariable/afterStatements.java

@@ -3,13 +3,11 @@ import java.util.function.Consumer;
 class Test {
     void foo(String s) {
     if (true) {
-        Consumer<String> consumer = new Consumer<String>() {
-            public void accept(String s) {
-                System.out.println("Hello, world " + s);
-                System.out.println();
-            }
+        Consumer<String> stringConsumer = s1 -> {
+            System.out.println("Hello, world " + s1);
+            System.out.println();
         };
-        consumer.accept(s);
+        stringConsumer.accept(s);
       
         System.out.println();
     }