/*
* Copyright 2000-2017 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.refactoring.chainCall;
import com.intellij.codeInspection.LambdaCanBeMethodReferenceInspection;
import com.intellij.codeInspection.util.OptionalUtil;
import com.intellij.openapi.extensions.ExtensionPointName;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.util.text.StringUtil;
import com.intellij.psi.*;
import com.intellij.psi.codeStyle.CodeStyleManager;
import com.intellij.psi.util.PsiTreeUtil;
import com.intellij.refactoring.util.LambdaRefactoringUtil;
import com.intellij.refactoring.util.RefactoringUtil;
import com.intellij.util.ArrayUtil;
import com.siyeh.ig.psiutils.ExpressionUtils;
import org.jetbrains.annotations.Contract;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import static com.intellij.util.ObjectUtils.tryCast;
/**
* @author Tagir Valeev
*/
public interface ChainCallExtractor {
ExtensionPointName<ChainCallExtractor> KEY = ExtensionPointName.create("com.intellij.java.refactoring.chainCallExtractor");
/**
* Returns true if the mapping chain call can be extracted from lambda passed to the given call.
*
* @param call call to check
* @param expression expression to extract
* @param expressionType resulting type of the extracted expression
* @return true if this extractor can create a mapping step from given expression
*/
boolean canExtractChainCall(@NotNull PsiMethodCallExpression call, PsiExpression expression, PsiType expressionType);
/**
* Returns chain call string representation (starting from "." like {@code .map(x -> x.getName())}).
*
* @param variable variable to be used as chain call input
* @param expression mapping expression
* @param expressionType target expression type
* @return chain call. Result is correct only if {@link #canExtractChainCall} was checked before
* for given expression and expressionType
*/
default String buildChainCall(PsiVariable variable, PsiExpression expression, PsiType expressionType) {
if(expression instanceof PsiArrayInitializerExpression) {
expression = RefactoringUtil.convertInitializerToNormalExpression(expression, expressionType);
}
String typeArgument = OptionalUtil.getMapTypeArgument(expression, expressionType);
return "." + typeArgument + getMethodName(variable, expression, expressionType) +
"(" + variable.getName() + "->" + expression.getText() + ")";
}
/**
* Returns a name of the method to be extracted
*
* @param variable variable to be used as chain call input
* @param expression mapping expression
* @param expressionType target expression type
* @return chain call. Result is correct only if {@link #canExtractChainCall} was checked before
* for given expression and expressionType
*/
String getMethodName(PsiVariable variable, PsiExpression expression, PsiType expressionType);
/**
* Returns new name for the existing call from which element is to be extracted. Sometimes it should be renamed
* depending on the new element type (e.g. {@code map} to {@code mapToObj}).
*
* @param call call to fix the name
* @param newElementType new element type (to be passed as lambda parameter)
* @return new call name. Default implementation returns current name.
*/
default String fixCallName(PsiMethodCallExpression call, PsiType newElementType) {
return call.getMethodExpression().getReferenceName();
}
@Contract("null, _, _ -> null")
static ChainCallExtractor findExtractor(@Nullable PsiLambdaExpression lambda, PsiExpression expression, PsiType targetType) {
if (lambda == null) return null;
PsiParameterList parameters = lambda.getParameterList();
if (parameters.getParametersCount() != 1) return null;
PsiExpressionList args = tryCast(lambda.getParent(), PsiExpressionList.class);
if (args == null || args.getExpressions().length != 1) return null;
PsiParameter parameter = parameters.getParameters()[0];
if (ExpressionUtils.isReferenceTo(expression, parameter) && parameter.getType().equals(targetType)) {
// No-op extraction is useless
return null;
}
PsiMethodCallExpression call = tryCast(args.getParent(), PsiMethodCallExpression.class);
if (call == null) return null;
for(ChainCallExtractor extractor : KEY.getExtensions()) {
if(extractor.canExtractChainCall(call, expression, targetType) &&
StringUtil.isNotEmpty(extractor.getMethodName(parameter, expression, targetType))) {
return extractor;
}
}
return null;
}
static PsiLambdaExpression extractMappingStep(@NotNull Project project, PsiLocalVariable variable) {
if (variable == null) return null;
String name = variable.getName();
if (name == null) return null;
PsiExpression initializer = variable.getInitializer();
if (initializer == null) return null;
PsiLambdaExpression lambda = PsiTreeUtil.getParentOfType(variable, PsiLambdaExpression.class);
if (lambda == null) return null;
PsiMethodCallExpression call = PsiTreeUtil.getParentOfType(lambda, PsiMethodCallExpression.class);
if (call == null) return null;
PsiExpression qualifier = call.getMethodExpression().getQualifierExpression();
if (qualifier == null) return null;
String methodName = call.getMethodExpression().getReferenceName();
if (methodName == null) return null;
PsiParameter parameter = ArrayUtil.getFirstElement(lambda.getParameterList().getParameters());
if (parameter == null) return null;
ChainCallExtractor extractor = findExtractor(lambda, initializer, variable.getType());
if (extractor == null) return null;
String newMethodName = extractor.fixCallName(call, variable.getType());
String mapOperation = extractor.buildChainCall(parameter, initializer, variable.getType());
PsiElementFactory factory = JavaPsiFacade.getElementFactory(project);
if (!mapOperation.isEmpty()) {
qualifier = (PsiExpression)qualifier.replace(factory.createExpressionFromText(qualifier.getText() + mapOperation, qualifier));
}
parameter = (PsiParameter)parameter.replace(factory.createParameter(variable.getName(), variable.getType(), parameter));
variable.delete();
LambdaRefactoringUtil.simplifyToExpressionLambda(lambda);
PsiTypeElement typeElement = parameter.getTypeElement();
if (typeElement != null) {
typeElement.delete();
}
ExpressionUtils.bindCallTo(call, newMethodName);
if (qualifier instanceof PsiMethodCallExpression) {
PsiLambdaExpression newLambda =
tryCast(ArrayUtil.getFirstElement(((PsiMethodCallExpression)qualifier).getArgumentList().getExpressions()),
PsiLambdaExpression.class);
if (newLambda != null) {
LambdaCanBeMethodReferenceInspection.replaceLambdaWithMethodReference(newLambda);
}
}
call = (PsiMethodCallExpression)CodeStyleManager.getInstance(project).reformat(call);
return tryCast(ArrayUtil.getFirstElement(call.getArgumentList().getExpressions()), PsiLambdaExpression.class);
}
}