| /* |
| * Copyright 2000-2012 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.codeInsight.daemon.GroupNames; |
| import com.intellij.openapi.diagnostic.Logger; |
| import com.intellij.openapi.project.Project; |
| import com.intellij.openapi.util.Ref; |
| import com.intellij.pom.java.LanguageLevel; |
| import com.intellij.psi.*; |
| import com.intellij.psi.codeStyle.JavaCodeStyleManager; |
| import com.intellij.psi.util.PsiTreeUtil; |
| import com.intellij.psi.util.PsiUtil; |
| import com.intellij.util.ArrayUtilRt; |
| import org.jetbrains.annotations.Nls; |
| import org.jetbrains.annotations.NotNull; |
| import org.jetbrains.annotations.Nullable; |
| |
| /** |
| * User: anna |
| */ |
| public class LambdaCanBeMethodReferenceInspection extends BaseJavaBatchLocalInspectionTool { |
| public static final Logger LOG = Logger.getInstance("#" + LambdaCanBeMethodReferenceInspection.class.getName()); |
| |
| @Nls |
| @NotNull |
| @Override |
| public String getGroupDisplayName() { |
| return GroupNames.LANGUAGE_LEVEL_SPECIFIC_GROUP_NAME; |
| } |
| |
| @Nls |
| @NotNull |
| @Override |
| public String getDisplayName() { |
| return "Lambda can be replaced with method reference"; |
| } |
| |
| @Override |
| public boolean isEnabledByDefault() { |
| return true; |
| } |
| |
| @NotNull |
| @Override |
| public String getShortName() { |
| return "Convert2MethodRef"; |
| } |
| |
| @NotNull |
| @Override |
| public PsiElementVisitor buildVisitor(@NotNull final ProblemsHolder holder, boolean isOnTheFly) { |
| return new JavaElementVisitor() { |
| @Override |
| public void visitLambdaExpression(PsiLambdaExpression expression) { |
| super.visitLambdaExpression(expression); |
| if (PsiUtil.getLanguageLevel(expression).isAtLeast(LanguageLevel.JDK_1_8)) { |
| final PsiElement body = expression.getBody(); |
| final PsiCallExpression callExpression = canBeMethodReferenceProblem(body, expression.getParameterList().getParameters(), expression.getFunctionalInterfaceType()); |
| if (callExpression != null) { |
| holder.registerProblem(callExpression, |
| "Can be replaced with method reference", |
| ProblemHighlightType.GENERIC_ERROR_OR_WARNING, new ReplaceWithMethodRefFix()); |
| } |
| } |
| } |
| }; |
| } |
| |
| @Nullable |
| protected static PsiCallExpression canBeMethodReferenceProblem(@Nullable final PsiElement body, |
| final PsiParameter[] parameters, |
| PsiType functionalInterfaceType) { |
| PsiCallExpression methodCall = null; |
| if (body instanceof PsiCallExpression) { |
| methodCall = (PsiCallExpression)body; |
| } |
| else if (body instanceof PsiCodeBlock) { |
| final PsiStatement[] statements = ((PsiCodeBlock)body).getStatements(); |
| if (statements.length == 1) { |
| if (statements[0] instanceof PsiReturnStatement) { |
| final PsiExpression returnValue = ((PsiReturnStatement)statements[0]).getReturnValue(); |
| if (returnValue instanceof PsiCallExpression) { |
| methodCall = (PsiCallExpression)returnValue; |
| } |
| } |
| else if (statements[0] instanceof PsiExpressionStatement) { |
| final PsiExpression expr = ((PsiExpressionStatement)statements[0]).getExpression(); |
| if (expr instanceof PsiCallExpression) { |
| methodCall = (PsiCallExpression)expr; |
| } |
| } |
| } |
| } |
| |
| if (methodCall != null) { |
| final PsiExpressionList argumentList = methodCall.getArgumentList(); |
| if (argumentList != null) { |
| final PsiExpression[] expressions = argumentList.getExpressions(); |
| |
| final PsiMethod psiMethod = methodCall.resolveMethod(); |
| final PsiClass containingClass; |
| boolean isConstructor; |
| if (psiMethod == null) { |
| isConstructor = true; |
| if (!(methodCall instanceof PsiNewExpression)) return null; |
| if (((PsiNewExpression)methodCall).getAnonymousClass() != null) return null; |
| final PsiJavaCodeReferenceElement classReference = ((PsiNewExpression)methodCall).getClassOrAnonymousClassReference(); |
| if (classReference == null) return null; |
| containingClass = (PsiClass)classReference.resolve(); |
| } |
| else { |
| containingClass = psiMethod.getContainingClass(); |
| isConstructor = psiMethod.isConstructor(); |
| } |
| if (containingClass == null) return null; |
| boolean isReceiverType = PsiMethodReferenceUtil.isReceiverType(functionalInterfaceType, containingClass, psiMethod); |
| final boolean staticOrValidConstructorRef; |
| if (isConstructor) { |
| staticOrValidConstructorRef = |
| (containingClass.getContainingClass() == null || containingClass.hasModifierProperty(PsiModifier.STATIC)); |
| } |
| else { |
| staticOrValidConstructorRef = psiMethod.hasModifierProperty(PsiModifier.STATIC); |
| } |
| |
| final int offset = isReceiverType && !staticOrValidConstructorRef ? 1 : 0; |
| if (parameters.length != expressions.length + offset) return null; |
| |
| for (int i = 0; i < expressions.length; i++) { |
| PsiExpression psiExpression = expressions[i]; |
| if (!(psiExpression instanceof PsiReferenceExpression)) return null; |
| final PsiElement resolve = ((PsiReferenceExpression)psiExpression).resolve(); |
| if (resolve == null) return null; |
| if (parameters[i + offset] != resolve) return null; |
| } |
| |
| final PsiExpression qualifierExpression; |
| if (methodCall instanceof PsiMethodCallExpression) { |
| qualifierExpression = ((PsiMethodCallExpression)methodCall).getMethodExpression().getQualifierExpression(); |
| } |
| else if (methodCall instanceof PsiNewExpression) { |
| qualifierExpression = ((PsiNewExpression)methodCall).getQualifier(); |
| } |
| else { |
| qualifierExpression = null; |
| } |
| if (offset > 0) { |
| if (!(qualifierExpression instanceof PsiReferenceExpression) || |
| ((PsiReferenceExpression)qualifierExpression).resolve() != parameters[0]) { |
| return null; |
| } |
| } |
| else if (qualifierExpression != null) { |
| final Ref<Boolean> usedInQualifier = new Ref<Boolean>(false); |
| qualifierExpression.accept(new JavaRecursiveElementWalkingVisitor() { |
| @Override |
| public void visitReferenceExpression(PsiReferenceExpression expression) { |
| final PsiElement resolve = expression.resolve(); |
| if (resolve instanceof PsiParameter && ArrayUtilRt.find(parameters, resolve) > -1) { |
| usedInQualifier.set(true); |
| return; |
| } |
| super.visitReferenceExpression(expression); |
| } |
| |
| @Override |
| public void visitMethodCallExpression(PsiMethodCallExpression expression) { |
| usedInQualifier.set(true); |
| super.visitMethodCallExpression(expression); |
| } |
| }); |
| if (usedInQualifier.get()) return null; |
| } |
| return methodCall; |
| } else if (methodCall instanceof PsiNewExpression) { |
| final PsiExpression[] dimensions = ((PsiNewExpression)methodCall).getArrayDimensions(); |
| if (dimensions.length > 0) { |
| final PsiMethod interfaceMethod = LambdaUtil.getFunctionalInterfaceMethod(functionalInterfaceType); |
| if (interfaceMethod != null) { |
| final PsiParameter[] psiParameters = interfaceMethod.getParameterList().getParameters(); |
| if (psiParameters.length == 1 && PsiType.INT.equals(psiParameters[0].getType())) { |
| return methodCall; |
| } |
| } |
| } |
| } |
| } |
| return null; |
| } |
| |
| @Nullable |
| protected static String createMethodReferenceText(PsiElement element, PsiType functionalInterfaceType) { |
| String methodRefText = null; |
| if (element instanceof PsiMethodCallExpression) { |
| final PsiMethodCallExpression methodCall = (PsiMethodCallExpression)element; |
| final PsiMethod psiMethod = methodCall.resolveMethod(); |
| if (psiMethod == null) return null; |
| final PsiClass containingClass = psiMethod.getContainingClass(); |
| LOG.assertTrue(containingClass != null); |
| final PsiReferenceExpression methodExpression = methodCall.getMethodExpression(); |
| final PsiExpression qualifierExpression = methodExpression.getQualifierExpression(); |
| final String methodReferenceName = methodExpression.getReferenceName(); |
| if (qualifierExpression != null) { |
| boolean isReceiverType = PsiMethodReferenceUtil.isReceiverType(functionalInterfaceType, containingClass, psiMethod); |
| final String qualifier; |
| if (isReceiverType) { |
| final PsiType qualifierExpressionType = qualifierExpression.getType(); |
| qualifier = qualifierExpressionType != null ? qualifierExpressionType.getCanonicalText() : getClassReferenceName(containingClass); |
| } |
| else { |
| qualifier = qualifierExpression.getText(); |
| } |
| methodRefText = qualifier + "::" + ((PsiMethodCallExpression)element).getTypeArgumentList().getText() + methodReferenceName; |
| } |
| else { |
| methodRefText = |
| (psiMethod.hasModifierProperty(PsiModifier.STATIC) ? getClassReferenceName(containingClass) : "this") + "::" + methodReferenceName; |
| } |
| } |
| else if (element instanceof PsiNewExpression) { |
| final PsiMethod constructor = ((PsiNewExpression)element).resolveConstructor(); |
| PsiClass containingClass = null; |
| if (constructor != null) { |
| containingClass = constructor.getContainingClass(); |
| LOG.assertTrue(containingClass != null); |
| } |
| else { |
| final PsiJavaCodeReferenceElement classReference = ((PsiNewExpression)element).getClassOrAnonymousClassReference(); |
| if (classReference != null) { |
| final JavaResolveResult resolve = classReference.advancedResolve(false); |
| final PsiElement resolveElement = resolve.getElement(); |
| if (resolveElement instanceof PsiClass) { |
| containingClass = (PsiClass)resolveElement; |
| } |
| } |
| } |
| final PsiType newExprType = ((PsiNewExpression)element).getType(); |
| if (containingClass != null) { |
| methodRefText = getClassReferenceName(containingClass); |
| } else if (newExprType instanceof PsiArrayType){ |
| final PsiType deepComponentType = newExprType.getDeepComponentType(); |
| if (deepComponentType instanceof PsiPrimitiveType) { |
| methodRefText = deepComponentType.getCanonicalText(); |
| } |
| } |
| |
| if (methodRefText != null) { |
| if (newExprType != null) { |
| int dim = newExprType.getArrayDimensions(); |
| while (dim-- > 0) { |
| methodRefText += "[]"; |
| } |
| } |
| methodRefText += "::new"; |
| } |
| } |
| return methodRefText; |
| } |
| |
| private static String getClassReferenceName(PsiClass containingClass) { |
| final String qualifiedName = containingClass.getQualifiedName(); |
| return qualifiedName != null ? qualifiedName : containingClass.getName(); |
| } |
| |
| private static class ReplaceWithMethodRefFix implements LocalQuickFix { |
| @NotNull |
| @Override |
| public String getName() { |
| return "Replace lambda with method reference"; |
| } |
| |
| @NotNull |
| @Override |
| public String getFamilyName() { |
| return getName(); |
| } |
| |
| @Override |
| public void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor) { |
| final PsiElement element = descriptor.getPsiElement(); |
| final PsiLambdaExpression lambdaExpression = PsiTreeUtil.getParentOfType(element, PsiLambdaExpression.class); |
| if (lambdaExpression == null) return; |
| final PsiType functionalInterfaceType = lambdaExpression.getFunctionalInterfaceType(); |
| final String methodRefText = createMethodReferenceText(element, functionalInterfaceType); |
| |
| if (methodRefText != null) { |
| final PsiElementFactory factory = JavaPsiFacade.getElementFactory(project); |
| final PsiExpression psiExpression = |
| factory.createExpressionFromText(methodRefText, lambdaExpression); |
| PsiElement replace = lambdaExpression.replace(psiExpression); |
| if (((PsiMethodReferenceExpression)replace).getFunctionalInterfaceType() == null) { //ambiguity |
| final PsiTypeCastExpression cast = (PsiTypeCastExpression)factory.createExpressionFromText("(A)a", replace); |
| cast.getCastType().replace(factory.createTypeElement(functionalInterfaceType)); |
| cast.getOperand().replace(replace); |
| replace = replace.replace(cast); |
| } |
| JavaCodeStyleManager.getInstance(project).shortenClassReferences(replace); |
| } |
| } |
| } |
| } |
