IG: new "Overly long lambda expression" inspection

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/META-INF/InspectionGadgets.xml

@@ -1631,6 +1631,9 @@
                      key="non.comment.source.statements.display.name" groupBundle="messages.InspectionsBundle"
                      groupKey="group.names.method.metrics" enabledByDefault="false" level="WARNING"
                      implementationClass="com.siyeh.ig.methodmetrics.NonCommentSourceStatementsInspection"/>
+    <localInspection groupPath="Java" language="JAVA" shortName="OverlyLongLambda" bundle="com.siyeh.InspectionGadgetsBundle"
+                     key="overly.long.lambda.display.name" groupBundle="messages.InspectionsBundle" groupKey="group.names.method.metrics"
+                     enabledByDefault="false" level="WARNING" implementationClass="com.siyeh.ig.methodmetrics.OverlyLongLambdaInspection"/>
     <localInspection groupPath="Java" language="JAVA" suppressId="MethodWithTooManyParameters" shortName="ParametersPerMethod" bundle="com.siyeh.InspectionGadgetsBundle"
                      key="parameters.per.method.display.name" groupBundle="messages.InspectionsBundle" groupKey="group.names.method.metrics"
                      enabledByDefault="false" level="WARNING"

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/InspectionGadgetsBundle.properties

@@ -2197,4 +2197,6 @@ array.creation.without.new.keyword.family.quickfix=Add 'new' expression
 malformed.set.up.tear.down.display.name=Malformed 'setUp()' or 'tearDown()'
 malformed.set.up.tear.down.problem.descriptor='#ref()' has incorrect signature #loc
 method.missing.return.statement.display.name=Method contains logic but is missing a 'return' statement
-method.missing.return.statement.problem.descriptor=Method <code>#ref</code> contains logic but is missing a 'return' statement
+method.missing.return.statement.problem.descriptor=Method <code>#ref</code> contains logic but is missing a 'return' statement
+overly.long.lambda.display.name=Overly long lambda expression
+overly.long.lambda.problem.descriptor=Lambda expression is too long (# Non-comment source statements = {0}) #loc

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/methodmetrics/OverlyLongLambdaInspection.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2000-2016 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.methodmetrics;
+
+import com.intellij.psi.*;
+import com.siyeh.InspectionGadgetsBundle;
+import com.siyeh.ig.BaseInspectionVisitor;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class OverlyLongLambdaInspection extends MethodMetricInspection {
+
+  private static final int DEFAULT_LIMIT = 3;
+
+  @Override
+  @NotNull
+  public String getDisplayName() {
+    return InspectionGadgetsBundle.message("overly.long.lambda.display.name");
+  }
+
+  @Override
+  protected int getDefaultLimit() {
+    return DEFAULT_LIMIT;
+  }
+
+  @Override
+  protected String getConfigurationLabel() {
+    return InspectionGadgetsBundle.message("non.comment.source.statements.limit.option");
+  }
+
+  @Override
+  @NotNull
+  public String buildErrorString(Object... infos) {
+    final Integer statementCount = (Integer)infos[0];
+    return InspectionGadgetsBundle.message("overly.long.lambda.problem.descriptor", statementCount);
+  }
+
+  @Override
+  public BaseInspectionVisitor buildVisitor() {
+    return new OverlyLongLambdaVisitor();
+  }
+
+  private class OverlyLongLambdaVisitor extends BaseInspectionVisitor {
+
+    @Override
+    public void visitLambdaExpression(PsiLambdaExpression expression) {
+      final PsiElement body = expression.getBody();
+      if (!(body instanceof PsiCodeBlock)) {
+        return;
+      }
+      final PsiCodeBlock block = (PsiCodeBlock)body;
+      final PsiJavaToken brace = block.getLBrace();
+      if (brace == null) {
+        return;
+      }
+      final NCSSVisitor visitor = new NCSSVisitor();
+      block.accept(visitor);
+      final int count = visitor.getStatementCount();
+      if (count <= getLimit()) {
+        return;
+      }
+      registerErrorAtOffset(expression, 0, body.getStartOffsetInParent() + 1, Integer.valueOf(count));
+    }
+  }
+}

plugins/InspectionGadgets/src/inspectionDescriptions/OverlyLongLambda.html

@@ -0,0 +1,12 @@
+<html>
+<body>
+Reports lambda expressions that are too long.
+Lambda expressions that are too long
+may be confusing, and it is often better to extract the statements into their own method.
+<!-- tooltip end -->
+<p>
+Use the field below to specify the maximum number of non-comment source statements a lambda expression is allowed to have.
+<p>
+<small>New in 2016.3</small>
+</body>
+</html>

plugins/InspectionGadgets/testsrc/com/siyeh/ig/methodmetrics/OverlyLongLambdaInspectionTest.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2000-2016 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.methodmetrics;
+
+import com.intellij.codeInspection.InspectionProfileEntry;
+import com.siyeh.ig.LightInspectionTestCase;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class OverlyLongLambdaInspectionTest extends LightInspectionTestCase {
+
+  public void testSimple() {
+    doStatementTest("Runnable r = /*Lambda is too long (# Non-comment source statements = 4)*/() -> {/**/" +
+                    "  System.out.println();" +
+                    "  System.out.println();" +
+                    "  System.out.println();" +
+                    "  System.out.println();" +
+                    "};");
+  }
+
+  @Nullable
+  @Override
+  protected InspectionProfileEntry getInspection() {
+    return new OverlyLongLambdaInspection();
+  }
+}