IDEA-163909 Inspection to replace computeIfAbsent returning a constant with putIfAbsent

java/java-impl/src/com/intellij/codeInspection/ExcessiveLambdaUsageInspection.java

@@ -0,0 +1,142 @@
+/*
+ * 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.intellij.codeInspection;
+
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.util.TextRange;
+import com.intellij.psi.*;
+import com.intellij.psi.util.InheritanceUtil;
+import com.intellij.psi.util.PsiTreeUtil;
+import com.intellij.psi.util.PsiUtil;
+import com.siyeh.ig.psiutils.CommentTracker;
+import com.siyeh.ig.psiutils.ExpressionUtils;
+import org.jetbrains.annotations.Nls;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.stream.Stream;
+
+/**
+ * @author Tagir Valeev
+ */
+public class ExcessiveLambdaUsageInspection extends BaseJavaBatchLocalInspectionTool {
+  private static final ExcessiveLambdaInfo[] INFOS = {
+    new ExcessiveLambdaInfo(CommonClassNames.JAVA_UTIL_MAP, "computeIfAbsent", "putIfAbsent", 1, false),
+    new ExcessiveLambdaInfo(CommonClassNames.JAVA_UTIL_OPTIONAL, "orElseGet", "orElse", 0, true),
+    new ExcessiveLambdaInfo("java.util.OptionalInt", "orElseGet", "orElse", 0, true),
+    new ExcessiveLambdaInfo("java.util.OptionalLong", "orElseGet", "orElse", 0, true),
+    new ExcessiveLambdaInfo("java.util.OptionalDouble", "orElseGet", "orElse", 0, true),
+    new ExcessiveLambdaInfo("java.util.OptionalDouble", "orElseGet", "orElse", 0, true),
+    new ExcessiveLambdaInfo("com.google.common.base.Optional", "or", "or", 0, true),
+    new ExcessiveLambdaInfo("java.util.Objects", "requireNonNull", "requireNonNull", 1, true)
+  };
+
+  @NotNull
+  @Override
+  public PsiElementVisitor buildVisitor(@NotNull ProblemsHolder holder, boolean isOnTheFly) {
+    if (!PsiUtil.isLanguageLevel8OrHigher(holder.getFile())) {
+      return PsiElementVisitor.EMPTY_VISITOR;
+    }
+    return new JavaElementVisitor() {
+      @Override
+      public void visitLambdaExpression(PsiLambdaExpression lambda) {
+        PsiElement parent = lambda.getParent();
+        if (!(parent instanceof PsiExpressionList)) return;
+        PsiElement gParent = parent.getParent();
+        if (!(gParent instanceof PsiMethodCallExpression)) return;
+        if (!(lambda.getBody() instanceof PsiExpression)) return;
+        PsiExpression expr = (PsiExpression)lambda.getBody();
+        if (!ExpressionUtils.isSimpleExpression(expr)) return;
+        if (Stream.of(lambda.getParameterList().getParameters()).anyMatch(param -> ExpressionUtils.isReferenceTo(expr, param))) return;
+
+        for (ExcessiveLambdaInfo info : INFOS) {
+          if(info.isApplicable((PsiMethodCallExpression)gParent, lambda)) {
+            holder.registerProblem(lambda, InspectionsBundle.message("inspection.excessive.lambda.message"),
+                                   ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                                   new TextRange(0, expr.getTextOffset() - lambda.getTextOffset()), new RemoveExcessiveLambdaFix(info));
+          }
+        }
+      }
+    };
+  }
+
+  static class RemoveExcessiveLambdaFix implements LocalQuickFix {
+    private final ExcessiveLambdaInfo myInfo;
+
+    public RemoveExcessiveLambdaFix(ExcessiveLambdaInfo info) {
+      myInfo = info;
+    }
+
+    @Nls
+    @NotNull
+    @Override
+    public String getName() {
+      return InspectionsBundle.message("inspection.excessive.lambda.fix.name", myInfo.myConstantMethod);
+    }
+
+    @Nls
+    @NotNull
+    @Override
+    public String getFamilyName() {
+      return InspectionsBundle.message("inspection.excessive.lambda.fix.family.name");
+    }
+
+    @Override
+    public void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor) {
+      PsiElement element = descriptor.getStartElement();
+      if(!(element instanceof PsiLambdaExpression)) return;
+      PsiLambdaExpression lambda = (PsiLambdaExpression)element;
+      PsiElement body = lambda.getBody();
+      if(body == null) return;
+      PsiMethodCallExpression call = PsiTreeUtil.getParentOfType(lambda, PsiMethodCallExpression.class);
+      if(call == null) return;
+
+      call.getMethodExpression().handleElementRename(myInfo.myConstantMethod);
+      CommentTracker ct = new CommentTracker();
+      PsiElementFactory factory = JavaPsiFacade.getElementFactory(project);
+      ct.replaceAndRestoreComments(lambda, factory.createExpressionFromText(ct.text(body), lambda));
+    }
+  }
+
+  static class ExcessiveLambdaInfo {
+    final String myClass;
+    final String myLambdaMethod;
+    final String myConstantMethod;
+    final int myParameterIndex;
+    final boolean myCanUseReturnValue;
+
+    ExcessiveLambdaInfo(String aClass, String lambdaMethod, String constantMethod, int index, boolean canUseReturnValue) {
+      myClass = aClass;
+      myLambdaMethod = lambdaMethod;
+      myConstantMethod = constantMethod;
+      myParameterIndex = index;
+      myCanUseReturnValue = canUseReturnValue;
+    }
+
+    boolean isApplicable(PsiMethodCallExpression call, PsiLambdaExpression lambda) {
+      if(!myLambdaMethod.equals(call.getMethodExpression().getReferenceName())) return false;
+      if(!myCanUseReturnValue && !(call.getParent() instanceof PsiExpressionStatement)) return false;
+      PsiExpression[] args = call.getArgumentList().getExpressions();
+      if(args.length <= myParameterIndex || args[myParameterIndex] != lambda) return false;
+      PsiMethod method = call.resolveMethod();
+      if(method == null) return false;
+      PsiParameter[] parameters = method.getParameterList().getParameters();
+      if(parameters.length <= myParameterIndex) return false;
+      PsiClass fnClass = PsiUtil.resolveClassInClassTypeOnly(parameters[myParameterIndex].getType());
+      return fnClass != null && LambdaUtil.getFunction(fnClass) != null &&
+             InheritanceUtil.isInheritor(method.getContainingClass(), false, myClass);
+    }
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/excessiveLambdaUsage/afterComputeIfAbsent.java

@@ -0,0 +1,10 @@
+// "Use 'putIfAbsent' method without lambda" "true"
+import java.util.Map;
+
+class Test {
+    public void test(Map<String, String> map, String key) {
+        /*comment in param*/
+        /*comment in arrow*/
+        map.putIfAbsent(key, (/*comment in parens*/"empty"));
+    }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/excessiveLambdaUsage/afterGuavaOptional.java

@@ -0,0 +1,17 @@
+// "Use 'or' method without lambda" "true"
+package com.google.common.base;
+
+interface Supplier<T> {
+    T supply();
+}
+
+abstract class Optional<T> {
+    abstract T or(T value);
+    abstract T or(Supplier<? extends T> supplier);
+}
+
+class Test {
+    public void test(Optional<String> opt) {
+        System.out.println(opt.or(""));
+    }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/excessiveLambdaUsage/afterOptional.java

@@ -0,0 +1,8 @@
+// "Use 'orElse' method without lambda" "true"
+import java.util.*;
+
+class Test {
+    public String test(List<String> data) {
+        return data.stream().filter(Objects::nonNull).findFirst().orElse(null);
+    }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/excessiveLambdaUsage/beforeComputeIfAbsent.java

@@ -0,0 +1,8 @@
+// "Use 'putIfAbsent' method without lambda" "true"
+import java.util.Map;
+
+class Test {
+    public void test(Map<String, String> map, String key) {
+        map.computeIfAbsent(key, (/*comment in param*/k) /*comment in arrow*/<caret>-> (/*comment in parens*/"empty"));
+    }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/excessiveLambdaUsage/beforeComputeIfAbsentNonTrivial.java

@@ -0,0 +1,8 @@
+// "Use 'putIfAbsent' method without lambda" "false"
+import java.util.Map;
+
+class Test {
+    public void test(Map<String, String> map, String key) {
+        map.computeIfAbsent(key, (/*comment in param*/k) /*comment in arrow*/<caret>-> (/*comment in parens*/"empty"+key));
+    }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/excessiveLambdaUsage/beforeComputeIfAbsentUsedResult.java

@@ -0,0 +1,8 @@
+// "Use 'putIfAbsent' method without lambda" "false"
+import java.util.Map;
+
+class Test {
+    public String test(Map<String, String> map, String key) {
+        return map.computeIfAbsent(key, k <caret>-> ("empty"));
+    }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/excessiveLambdaUsage/beforeGuavaOptional.java

@@ -0,0 +1,17 @@
+// "Use 'or' method without lambda" "true"
+package com.google.common.base;
+
+interface Supplier<T> {
+    T supply();
+}
+
+abstract class Optional<T> {
+    abstract T or(T value);
+    abstract T or(Supplier<? extends T> supplier);
+}
+
+class Test {
+    public void test(Optional<String> opt) {
+        System.out.println(opt.or(() <caret>-> ""));
+    }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/excessiveLambdaUsage/beforeGuavaOptionalSupplier.java

@@ -0,0 +1,17 @@
+// "Use 'or' method without lambda" "false"
+package com.google.common.base;
+
+interface Supplier<T> {
+    T supply();
+}
+
+abstract class Optional<T> {
+    abstract T or(T value);
+    abstract T or(Supplier<? extends T> supplier);
+}
+
+class Test {
+    public void test(Optional<Supplier<String>> opt) {
+        System.out.println(opt.or(() <caret>-> ""));
+    }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/excessiveLambdaUsage/beforeOptional.java

@@ -0,0 +1,8 @@
+// "Use 'orElse' method without lambda" "true"
+import java.util.*;
+
+class Test {
+    public String test(List<String> data) {
+        return data.stream().filter(Objects::nonNull).findFirst().orElseGet((<caret>) -> null);
+    }
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/quickFix/ExcessiveLambdaUsageInspectionTest.java

@@ -0,0 +1,38 @@
+/*
+ * 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.intellij.codeInsight.daemon.quickFix;
+
+import com.intellij.codeInspection.ExcessiveLambdaUsageInspection;
+import com.intellij.codeInspection.LocalInspectionTool;
+import org.jetbrains.annotations.NotNull;
+
+
+public class ExcessiveLambdaUsageInspectionTest extends LightQuickFixParameterizedTestCase {
+  @NotNull
+  @Override
+  protected LocalInspectionTool[] configureLocalInspectionTools() {
+    return new LocalInspectionTool[]{
+      new ExcessiveLambdaUsageInspection()
+    };
+  }
+
+  public void test() throws Exception { doAllTests(); }
+
+  @Override
+  protected String getBasePath() {
+    return "/codeInsight/daemonCodeAnalyzer/quickFix/excessiveLambdaUsage";
+  }
+}

platform/platform-resources-en/src/messages/InspectionsBundle.properties

@@ -738,4 +738,8 @@ inspection.tool.window.dialog.title=Inspection Tool Window
 inspection.tool.window.dialog.no.options=Inspection ''{0}'' has no configurable options
 inspection.tool.window.inspection.dialog.title=Inspection ''{0}'' options
 nullable.stuff.inspection.navigate.null.argument.usages.fix.family.name=Navigate to 'null' argument usages
-nullable.stuff.inspection.navigate.null.argument.usages.view.name=''null'' argument usages for parameter {0}
+nullable.stuff.inspection.navigate.null.argument.usages.view.name=''null'' argument usages for parameter {0}
+
+inspection.excessive.lambda.message=Excessive lambda usage
+inspection.excessive.lambda.fix.family.name=Replace lambda with constant
+inspection.excessive.lambda.fix.name=Use ''{0}'' method without lambda

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/psiutils/ExpressionUtils.java

@@ -699,6 +699,7 @@ public class ExpressionUtils {
    */
   @Contract("null -> false")
   public static boolean isSimpleExpression(@Nullable PsiExpression expression) {
+    expression = PsiUtil.skipParenthesizedExprDown(expression);
     if (expression instanceof PsiLiteralExpression ||
         expression instanceof PsiThisExpression ||
         expression instanceof PsiClassObjectAccessExpression) {

resources-en/src/inspectionDescriptions/ExcessiveLambdaUsage.html

@@ -0,0 +1,11 @@
+<html>
+<body>
+This inspection warns if trivial lambda expression is used where there's an alternative method which behaves the same way but
+accepts concrete value instead of lambda.
+<!-- tooltip end -->
+<p>
+  For example, <code>Optional.orElseGet(() -> null)</code> can be replaced with <code>Optional.orElse(null)</code>.
+</p>
+<small>New in 2017.1</small>
+</body>
+</html>

resources/src/META-INF/IdeaPlugin.xml

@@ -840,6 +840,11 @@
                      groupKey="group.names.language.level.specific.issues.and.migration.aids" enabledByDefault="true" level="WARNING"
                      implementationClass="com.intellij.codeInspection.java18api.Java8MapApiInspection"
                      displayName="Replace with single Map method"/>
+    <localInspection groupPath="Java" language="JAVA" shortName="ExcessiveLambdaUsage"
+                     groupBundle="messages.InspectionsBundle"
+                     groupKey="group.names.verbose.or.redundant.code.constructs" enabledByDefault="true" level="WARNING"
+                     implementationClass="com.intellij.codeInspection.ExcessiveLambdaUsageInspection"
+                     displayName="Excessive lambda usage"/>
     <localInspection groupPath="Java" language="JAVA" shortName="SimplifyStreamApiCallChains"
                      groupBundle="messages.InspectionsBundle"
                      groupKey="group.names.declaration.redundancy" enabledByDefault="true" level="WARNING"