dumb smart lambda completion (IDEA-112553)

java/java-impl/src/com/intellij/codeInsight/completion/JavaSmartCompletionContributor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2009 JetBrains s.r.o.
+ * Copyright 2000-2013 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,7 @@ import com.intellij.codeInsight.completion.scope.JavaCompletionProcessor;
 import com.intellij.codeInsight.lookup.*;
 import com.intellij.openapi.util.Key;
 import com.intellij.patterns.ElementPattern;
+import com.intellij.patterns.ElementPatternCondition;
 import com.intellij.patterns.PsiElementPattern;
 import com.intellij.patterns.PsiJavaPatterns;
 import com.intellij.psi.*;
@@ -28,6 +29,7 @@ import com.intellij.psi.filters.ElementFilter;
 import com.intellij.psi.filters.GeneratorFilter;
 import com.intellij.psi.filters.OrFilter;
 import com.intellij.psi.filters.getters.*;
+import com.intellij.psi.filters.position.FilterPattern;
 import com.intellij.psi.filters.types.AssignableFromFilter;
 import com.intellij.psi.filters.types.AssignableGroupFilter;
 import com.intellij.psi.filters.types.AssignableToFilter;
@@ -92,6 +94,21 @@ public class JavaSmartCompletionContributor extends CompletionContributor {
       psiElement().withText(")").withParent(PsiTypeCastExpression.class)));
   static final PsiElementPattern.Capture<PsiElement> IN_TYPE_ARGS =
     psiElement().inside(psiElement(PsiReferenceParameterList.class));
+  static final PsiElementPattern.Capture<PsiElement> LAMBDA = psiElement().and(new FilterPattern(new ElementFilter() {
+    @Override
+    public boolean isAcceptable(Object element, @Nullable PsiElement context) {
+      if (context == null) return false;
+      final PsiElement originalElement = context.getOriginalElement();
+      if (originalElement == null) return false;
+      final PsiElement rulezzRef = originalElement.getParent();
+      return LambdaUtil.isValidLambdaContext(rulezzRef.getParent());
+    }
+
+    @Override
+    public boolean isClassAcceptable(Class hintClass) {
+      return true;
+    }
+  }));
 
   @Nullable
   private static ElementFilter getReferenceFilter(PsiElement element) {
@@ -313,6 +330,8 @@ public class JavaSmartCompletionContributor extends CompletionContributor {
         }
       }
     });
+
+    extend(CompletionType.SMART, LAMBDA, new LambdaCompletionProvider());
   }
 
   private static void addExpectedTypeMembers(CompletionParameters params,

java/java-impl/src/com/intellij/codeInsight/completion/LambdaCompletionProvider.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2000-2013 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.codeInsight.completion;
+
+import com.intellij.codeInsight.ExpectedTypeInfo;
+import com.intellij.codeInsight.lookup.AutoCompletionPolicy;
+import com.intellij.codeInsight.lookup.LookupElement;
+import com.intellij.codeInsight.lookup.LookupElementBuilder;
+import com.intellij.openapi.editor.Editor;
+import com.intellij.openapi.editor.EditorModificationUtil;
+import com.intellij.openapi.util.text.StringUtil;
+import com.intellij.psi.*;
+import com.intellij.psi.util.PsiUtil;
+import com.intellij.util.Function;
+import com.intellij.util.ProcessingContext;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * User: anna
+ */
+public class LambdaCompletionProvider extends CompletionProvider<CompletionParameters> {
+  @Override
+  protected void addCompletions(@NotNull CompletionParameters parameters,
+                                ProcessingContext context,
+                                @NotNull CompletionResultSet result) {
+    if (!PsiUtil.isLanguageLevel8OrHigher(parameters.getOriginalFile())) return;
+    final ExpectedTypeInfo[] expectedTypes = JavaSmartCompletionContributor.getExpectedTypes(parameters);
+    for (ExpectedTypeInfo expectedType : expectedTypes) {
+      final PsiType defaultType = expectedType.getDefaultType();
+      if (LambdaHighlightingUtil.checkInterfaceFunctional(defaultType) == null) {
+        final PsiMethod method = LambdaUtil.getFunctionalInterfaceMethod(defaultType);
+        if (method != null) {
+          final PsiParameter[] params = method.getParameterList().getParameters();
+          final String paramsString = "(" + StringUtil.join(params, new Function<PsiParameter, String>() {
+            @Override
+            public String fun(PsiParameter parameter) {
+              return parameter.getName();
+            }
+          }, ",") + ")";
+          final LookupElementBuilder builder =
+            LookupElementBuilder.create(paramsString).withPresentableText(paramsString + " -> {}").withInsertHandler(new InsertHandler<LookupElement>() {
+              @Override
+              public void handleInsert(InsertionContext context, LookupElement item) {
+                final Editor editor = context.getEditor();
+                EditorModificationUtil.insertStringAtCaret(editor, " -> ");
+                PsiDocumentManager.getInstance(context.getProject()).commitDocument(editor.getDocument());
+              }
+            });
+          result.addElement(builder.withAutoCompletionPolicy(AutoCompletionPolicy.NEVER_AUTOCOMPLETE));
+        }
+      }
+    }
+  }
+}

java/java-psi-api/src/com/intellij/psi/LambdaUtil.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2012 JetBrains s.r.o.
+ * Copyright 2000-2013 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -93,7 +93,7 @@ public class LambdaUtil {
     return initialSubst;
   }
 
-  public static boolean isValidLambdaContext(PsiElement context) {
+  public static boolean isValidLambdaContext(@Nullable PsiElement context) {
     return context instanceof PsiTypeCastExpression ||
            context instanceof PsiAssignmentExpression ||
            context instanceof PsiVariable ||

java/java-tests/testData/codeInsight/completion/smartType/InLambdaPosition-out.java

@@ -0,0 +1,3 @@
+class Test {
+  Runnable r = () -> <caret>
+}

java/java-tests/testData/codeInsight/completion/smartType/InLambdaPosition.java

@@ -0,0 +1,3 @@
+class Test {
+  Runnable r = <caret>
+}

java/java-tests/testSrc/com/intellij/codeInsight/completion/SmartType18CompletionTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2012 JetBrains s.r.o.
+ * Copyright 2000-2013 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -66,6 +66,10 @@ public class SmartType18CompletionTest extends LightFixtureCompletionTestCase {
     doTest();
   }
 
+  public void testInLambdaPosition() throws Exception {
+    doTest();
+  }
+
   private void doTest() {
     configureByFile("/" + getTestName(false) + ".java");
     assertNotNull(myItems);