java/java-psi-impl/src/com/intellij/psi/impl/PsiDiamondTypeUtil.java

/*
 * Copyright 2000-2011 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.psi.impl;

import com.intellij.codeInsight.FileModificationService;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.util.text.StringUtil;
import com.intellij.pom.java.LanguageLevel;
import com.intellij.psi.*;
import com.intellij.psi.codeStyle.CodeStyleManager;
import com.intellij.psi.util.PsiTreeUtil;
import com.intellij.psi.util.PsiUtil;
import com.intellij.util.Function;
import org.jetbrains.annotations.Nullable;

import java.util.List;

/**
 * User: anna
 */
public class PsiDiamondTypeUtil {
  private static final Logger LOG = Logger.getInstance("#" + PsiDiamondTypeUtil.class.getName());

  private PsiDiamondTypeUtil() {
  }

  public static boolean canCollapseToDiamond(final PsiNewExpression expression,
                                             final PsiNewExpression context,
                                             @Nullable final PsiType expectedType) {
    return canCollapseToDiamond(expression, context, expectedType, false);
  }

  public static boolean canChangeContextForDiamond(final PsiNewExpression expression, final PsiType expectedType) {
    final PsiNewExpression copy = (PsiNewExpression)expression.copy();
    return canCollapseToDiamond(copy, copy, expectedType, true);
  }

  private static boolean canCollapseToDiamond(final PsiNewExpression expression,
                                             final PsiNewExpression context,
                                             @Nullable final PsiType expectedType,
                                             boolean skipDiamonds) {
    if (PsiUtil.getLanguageLevel(context).isAtLeast(LanguageLevel.JDK_1_7)) {
      final PsiJavaCodeReferenceElement classReference = expression.getClassOrAnonymousClassReference();
      if (classReference != null) {
        final PsiReferenceParameterList parameterList = classReference.getParameterList();
        if (parameterList != null) {
          final PsiTypeElement[] typeElements = parameterList.getTypeParameterElements();
          if (typeElements.length > 0) {
            if (!skipDiamonds && typeElements.length == 1 && typeElements[0].getType() instanceof PsiDiamondType) return false;
            final PsiDiamondTypeImpl.DiamondInferenceResult inferenceResult = PsiDiamondTypeImpl.resolveInferredTypes(expression, context);
            if (inferenceResult.getErrorMessage() == null) {
              final List<PsiType> types = inferenceResult.getInferredTypes();
              PsiType[] typeArguments = null;
              if (expectedType instanceof PsiClassType) {
                typeArguments = ((PsiClassType)expectedType).getParameters();
              }
              if (typeArguments == null) {
                typeArguments = parameterList.getTypeArguments();
              }
              if (types.size() == typeArguments.length) {
                for (int i = 0, typeArgumentsLength = typeArguments.length; i < typeArgumentsLength; i++) {
                  PsiType typeArgument = typeArguments[i];
                  if (types.get(i) instanceof PsiWildcardType) {
                    final PsiWildcardType wildcardType = (PsiWildcardType)types.get(i);
                    final PsiType bound = wildcardType.getBound();
                    if (bound != null) {
                      if (wildcardType.isExtends()) {
                        if (bound.isAssignableFrom(typeArgument)) continue;
                      }
                      else {
                        if (typeArgument.isAssignableFrom(bound)) continue;
                      }
                    }
                  }
                  if (!typeArgument.equals(types.get(i))) {
                    return false;
                  }
                }
              }
              return true;
            }
          }
        }
      }
    }
    return false;
  }

  public static PsiElement replaceExplicitWithDiamond(PsiElement psiElement) {
    if (psiElement instanceof PsiReferenceParameterList) {
      if (!FileModificationService.getInstance().prepareFileForWrite(psiElement.getContainingFile())) return psiElement;
      final PsiNewExpression expression =
        (PsiNewExpression)JavaPsiFacade.getElementFactory(psiElement.getProject()).createExpressionFromText("new a<>()", psiElement);
      final PsiJavaCodeReferenceElement classReference = expression.getClassReference();
      LOG.assertTrue(classReference != null);
      final PsiReferenceParameterList parameterList = classReference.getParameterList();
      LOG.assertTrue(parameterList != null);
      return psiElement.replace(parameterList);
    }
    return psiElement;
  }

  public static PsiElement replaceDiamondWithExplicitTypes(PsiElement element) {
    final PsiElement parent = element.getParent();
    if (!(parent instanceof PsiJavaCodeReferenceElement)) {
      return parent;
    }
    final PsiJavaCodeReferenceElement javaCodeReferenceElement =
            (PsiJavaCodeReferenceElement) parent;
    final PsiReferenceParameterList referenceParameterList =
            (PsiReferenceParameterList) element;
    final StringBuilder text = new StringBuilder();
    text.append(javaCodeReferenceElement.getQualifiedName());
    text.append('<');
    final PsiTypeElement[] typeElements = referenceParameterList.getTypeParameterElements();
    final PsiNewExpression newExpression = PsiTreeUtil.getParentOfType(typeElements[0], PsiNewExpression.class);
    final PsiDiamondType.DiamondInferenceResult result = PsiDiamondTypeImpl.resolveInferredTypesNoCheck(newExpression, newExpression);
    text.append(StringUtil.join(result.getInferredTypes(), new Function<PsiType, String>() {
      @Override
      public String fun(PsiType psiType) {
        return psiType.getCanonicalText();
      }
    }, ","));
    text.append('>');
    final PsiElementFactory elementFactory =
            JavaPsiFacade.getElementFactory(element.getProject());
    final PsiJavaCodeReferenceElement newReference =
            elementFactory.createReferenceFromText(text.toString(), element);
    return CodeStyleManager.getInstance(javaCodeReferenceElement.getProject()).reformat(javaCodeReferenceElement.replace(newReference));
  }

  public static PsiExpression expandTopLevelDiamondsInside(PsiExpression expr) {
    if (expr instanceof PsiNewExpression) {
      final PsiJavaCodeReferenceElement classReference = ((PsiNewExpression)expr).getClassReference();
      if (classReference != null) {
        final PsiReferenceParameterList parameterList = classReference.getParameterList();
        if (parameterList != null) {
          final PsiTypeElement[] typeParameterElements = parameterList.getTypeParameterElements();
          if (typeParameterElements.length == 1 && typeParameterElements[0].getType() instanceof PsiDiamondType) {
            return  (PsiExpression)replaceDiamondWithExplicitTypes(parameterList).getParent();
          }
        }
      }
    }
    return expr;
  }

  public static String getCollapsedType(PsiType type, PsiElement context) {
    String typeText = type.getCanonicalText();
    if (PsiUtil.isLanguageLevel7OrHigher(context)) {
      final int idx = typeText.indexOf('<');
      if (idx >= 0) {
        return typeText.substring(0, idx) + "<>";
      }
    }
    return typeText;
  }
}