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/*
* Copyright 2000-2013 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.completion;
import com.intellij.codeInsight.ExpectedTypeInfo;
import com.intellij.codeInsight.generation.GenerateMembersUtil;
import com.intellij.codeInsight.lookup.AutoCompletionPolicy;
import com.intellij.codeInsight.lookup.LookupElement;
import com.intellij.codeInsight.lookup.LookupElementBuilder;
import com.intellij.openapi.editor.Editor;
import com.intellij.openapi.editor.EditorModificationUtil;
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.codeStyle.JavaCodeStyleManager;
import com.intellij.psi.impl.source.resolve.graphInference.FunctionalInterfaceParameterizationUtil;
import com.intellij.psi.util.PsiUtil;
import com.intellij.util.Function;
import com.intellij.util.ProcessingContext;
import org.jetbrains.annotations.NotNull;
/**
* User: anna
*/
public class LambdaCompletionProvider extends CompletionProvider<CompletionParameters> {
@Override
protected void addCompletions(@NotNull CompletionParameters parameters,
ProcessingContext context,
@NotNull CompletionResultSet result) {
if (!PsiUtil.isLanguageLevel8OrHigher(parameters.getOriginalFile())) return;
final ExpectedTypeInfo[] expectedTypes = JavaSmartCompletionContributor.getExpectedTypes(parameters);
for (ExpectedTypeInfo expectedType : expectedTypes) {
final PsiType defaultType = expectedType.getDefaultType();
if (LambdaUtil.isFunctionalType(defaultType)) {
final PsiType functionalInterfaceType = FunctionalInterfaceParameterizationUtil.getGroundTargetType(defaultType);
final PsiMethod method = LambdaUtil.getFunctionalInterfaceMethod(functionalInterfaceType);
if (method != null) {
PsiParameter[] params = method.getParameterList().getParameters();
final Project project = method.getProject();
final PsiElement originalPosition = parameters.getOriginalPosition();
final JVMElementFactory jvmElementFactory = originalPosition != null ? JVMElementFactories.getFactory(originalPosition.getLanguage(), project) : null;
final JavaCodeStyleManager javaCodeStyleManager = JavaCodeStyleManager.getInstance(project);
if (jvmElementFactory != null) {
final PsiSubstitutor substitutor = LambdaUtil.getSubstitutor(method, PsiUtil.resolveGenericsClassInType(functionalInterfaceType));
params = GenerateMembersUtil.overriddenParameters(params, jvmElementFactory, javaCodeStyleManager, substitutor, originalPosition);
}
String paramsString =
params.length == 1 ? getParamName(params[0], javaCodeStyleManager, originalPosition) : "(" + StringUtil.join(params, new Function<PsiParameter, String>() {
@Override
public String fun(PsiParameter parameter) {
return getParamName(parameter, javaCodeStyleManager, originalPosition);
}
}, ",") + ")";
final CodeStyleManager codeStyleManager = CodeStyleManager.getInstance(project);
PsiLambdaExpression lambdaExpression = (PsiLambdaExpression)JavaPsiFacade.getElementFactory(project)
.createExpressionFromText(paramsString + " -> {}", null);
lambdaExpression = (PsiLambdaExpression)codeStyleManager.reformat(lambdaExpression);
paramsString = lambdaExpression.getParameterList().getText();
final LookupElementBuilder builder =
LookupElementBuilder.create(paramsString).withPresentableText(paramsString + " -> {}").withInsertHandler(new InsertHandler<LookupElement>() {
@Override
public void handleInsert(InsertionContext context, LookupElement item) {
final Editor editor = context.getEditor();
EditorModificationUtil.insertStringAtCaret(editor, " -> ");
}
});
result.addElement(builder.withAutoCompletionPolicy(AutoCompletionPolicy.NEVER_AUTOCOMPLETE));
}
}
}
}
private static String getParamName(PsiParameter param, JavaCodeStyleManager javaCodeStyleManager, PsiElement originalPosition) {
return javaCodeStyleManager.suggestUniqueVariableName(param.getName(), originalPosition, true);
}
}
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