new #ref() call uses the platform's default charset
+interface.may.be.annotated.functional.display.name=Interface may be annotated @FunctionalInterface
+interface.may.be.annotated.functional.problem.descriptor=Interface #ref may be annotated with @FunctionalInterface
diff --git a/plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/classlayout/InterfaceMayBeAnnotatedFunctionalInspection.java b/plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/classlayout/InterfaceMayBeAnnotatedFunctionalInspection.java
new file mode 100644
index 000000000000..13b134dcceb9
--- /dev/null
+++ b/plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/classlayout/InterfaceMayBeAnnotatedFunctionalInspection.java
@@ -0,0 +1,80 @@
+/*
+ * Copyright 2000-2014 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.siyeh.ig.classlayout;
+
+import com.intellij.codeInsight.intention.AddAnnotationPsiFix;
+import com.intellij.psi.LambdaHighlightingUtil;
+import com.intellij.psi.LambdaUtil;
+import com.intellij.psi.PsiClass;
+import com.intellij.psi.PsiNameValuePair;
+import com.intellij.psi.util.PsiUtil;
+import com.siyeh.InspectionGadgetsBundle;
+import com.siyeh.ig.BaseInspection;
+import com.siyeh.ig.BaseInspectionVisitor;
+import com.siyeh.ig.DelegatingFix;
+import com.siyeh.ig.InspectionGadgetsFix;
+import org.jetbrains.annotations.Nls;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class InterfaceMayBeAnnotatedFunctionalInspection extends BaseInspection {
+ @Nls
+ @NotNull
+ @Override
+ public String getDisplayName() {
+ return InspectionGadgetsBundle.message("interface.may.be.annotated.functional.display.name");
+ }
+
+ @NotNull
+ @Override
+ protected String buildErrorString(Object... infos) {
+ return InspectionGadgetsBundle.message("interface.may.be.annotated.functional.problem.descriptor");
+ }
+
+ @Nullable
+ @Override
+ protected InspectionGadgetsFix buildFix(Object... infos) {
+ final PsiClass aClass = (PsiClass)infos[0];
+ return new DelegatingFix(new AddAnnotationPsiFix(LambdaUtil.JAVA_LANG_FUNCTIONAL_INTERFACE, aClass, PsiNameValuePair.EMPTY_ARRAY));
+
+ }
+
+ @Override
+ public BaseInspectionVisitor buildVisitor() {
+ return new InterfaceMayBeAnnotatedFunctionalVisitor();
+ }
+
+ private static class InterfaceMayBeAnnotatedFunctionalVisitor extends BaseInspectionVisitor {
+
+ @Override
+ public void visitClass(PsiClass aClass) {
+ if (!PsiUtil.isLanguageLevel8OrHigher(aClass)) {
+ return;
+ }
+ super.visitClass(aClass);
+ if (!aClass.isInterface()) {
+ return;
+ }
+ if (LambdaHighlightingUtil.checkInterfaceFunctional(aClass) != null) {
+ return;
+ }
+ registerClassError(aClass, aClass);
+ }
+ }
+}
diff --git a/plugins/InspectionGadgets/src/inspectionDescriptions/InterfaceMayBeAnnotatedFunctional.html b/plugins/InspectionGadgets/src/inspectionDescriptions/InterfaceMayBeAnnotatedFunctional.html
new file mode 100644
index 000000000000..66ea1b4ac432
--- /dev/null
+++ b/plugins/InspectionGadgets/src/inspectionDescriptions/InterfaceMayBeAnnotatedFunctional.html
@@ -0,0 +1,10 @@
+
+
+Reports any interface that may be annotated as @FunctionalInterface, which is available in JDK 1.8.
+Annotating an interface with @FunctionalInterface can be useful to indicate that the interface is supposed to be functional and
+further abstract methods should not be added to it.
+This inspection only reports if the project or module is configured to use a language level of 8.0 or higher.
+
+New in 13.1
+
+
\ No newline at end of file
diff --git a/plugins/InspectionGadgets/testsrc/com/siyeh/ig/classlayout/InterfaceMayBeAnnotatedFunctionalInspectionTest.java b/plugins/InspectionGadgets/testsrc/com/siyeh/ig/classlayout/InterfaceMayBeAnnotatedFunctionalInspectionTest.java
new file mode 100644
index 000000000000..ab4e3e8f77f5
--- /dev/null
+++ b/plugins/InspectionGadgets/testsrc/com/siyeh/ig/classlayout/InterfaceMayBeAnnotatedFunctionalInspectionTest.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2000-2014 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.siyeh.ig.classlayout;
+
+import com.intellij.codeInspection.InspectionProfileEntry;
+import com.siyeh.ig.LightInspectionTestCase;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class InterfaceMayBeAnnotatedFunctionalInspectionTest extends LightInspectionTestCase {
+
+ public void testSimple() {
+ doTest("interface /*Interface 'Simple' may be annotated with @FunctionalInterface*/Simple/**/ {" +
+ " void f();" +
+ "}");
+ }
+
+ public void testLessSimple() {
+ doTest("interface /*Interface 'F' may be annotated with @FunctionalInterface*/F/**/ {" +
+ " boolean equals(Object o);" +
+ " static void f00() {}\n" +
+ " default void g() {}\n" +
+ " void f();\n" +
+ "}");
+ }
+
+ public void testNotFunctional() {
+ doTest("interface G {" +
+ "