JavaCharFilter.java

/*
 * Copyright 2000-2009 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.lookup.CharFilter;
import com.intellij.codeInsight.lookup.Lookup;
import com.intellij.codeInsight.lookup.LookupElement;
import com.intellij.lang.java.JavaLanguage;
import com.intellij.patterns.PsiJavaPatterns;
import com.intellij.pom.java.LanguageLevel;
import com.intellij.psi.*;
import com.intellij.psi.javadoc.PsiDocComment;
import com.intellij.psi.util.PsiTreeUtil;
import com.intellij.psi.util.PsiUtil;

public class JavaCharFilter extends CharFilter {

  private static boolean isWithinLiteral(final Lookup lookup) {
    PsiElement psiElement = lookup.getPsiElement();
    return psiElement != null && psiElement.getParent() instanceof PsiLiteralExpression;
  }

  @Override
  public Result acceptChar(char c, final int prefixLength, final Lookup lookup) {
    if (!lookup.getPsiFile().getLanguage().isKindOf(JavaLanguage.INSTANCE)) {
      return null;
    }

    LookupElement item = lookup.getCurrentItem();
    if (item == null || !item.isValid()) return null;

    final Object o = item.getObject();
    if (c == '!') {
      if (o instanceof PsiVariable) {
        if (PsiType.BOOLEAN.isAssignableFrom(((PsiVariable)o).getType())) return Result.SELECT_ITEM_AND_FINISH_LOOKUP;
      }
      if (o instanceof PsiMethod) {
        final PsiType type = ((PsiMethod)o).getReturnType();
        if (type != null && PsiType.BOOLEAN.isAssignableFrom(type)) return Result.SELECT_ITEM_AND_FINISH_LOOKUP;
      }
      if (o instanceof PsiKeyword && ((PsiKeyword)o).textMatches(PsiKeyword.INSTANCEOF)) {
        return Result.SELECT_ITEM_AND_FINISH_LOOKUP;
      }

      return null;
    }
    if (c == '.' && isWithinLiteral(lookup)) return Result.ADD_TO_PREFIX;

    if (c == ':') {
      PsiFile file = lookup.getPsiFile();
      PsiDocumentManager.getInstance(file.getProject()).commitDocument(lookup.getEditor().getDocument());
      PsiElement leaf = file.findElementAt(lookup.getEditor().getCaretModel().getOffset() - 1);
      if (PsiUtil.getLanguageLevel(file).isAtLeast(LanguageLevel.JDK_1_8)) {
        PsiStatement statement = PsiTreeUtil.getParentOfType(leaf, PsiStatement.class);
        if (statement == null ||
            statement.getTextRange().getStartOffset() != leaf.getTextRange().getStartOffset()) { // not typing a statement label
          return Result.SELECT_ITEM_AND_FINISH_LOOKUP;
        }
      }
      if (PsiTreeUtil.getParentOfType(leaf, PsiSwitchLabelStatement.class) != null ||
          PsiTreeUtil.getParentOfType(leaf, PsiConditionalExpression.class) != null) {
        return Result.SELECT_ITEM_AND_FINISH_LOOKUP;
      }
      return Result.HIDE_LOOKUP;
    }


    if (c == '[' || c == ']' || c == ')' || c == '>') return CharFilter.Result.SELECT_ITEM_AND_FINISH_LOOKUP;
    if (c == '<' && o instanceof PsiClass) return Result.SELECT_ITEM_AND_FINISH_LOOKUP;
    if (c == '(') {
      if (o instanceof PsiClass) {
        if (PsiJavaPatterns.psiElement().afterLeaf(PsiKeyword.NEW).accepts(lookup.getPsiElement())) {
          return Result.SELECT_ITEM_AND_FINISH_LOOKUP;
        }
        return Result.HIDE_LOOKUP;
      }
      if (o instanceof PsiType) {
        return Result.HIDE_LOOKUP;
      }
    }
    if ((c == ',' || c == '=') && o instanceof PsiVariable) {
      int lookupStart = lookup.getLookupStart();
      String name = ((PsiVariable)o).getName();
      if (lookupStart >= 0 && name != null && name.equals(lookup.itemPattern(item))) {
        return Result.HIDE_LOOKUP;
      }
    }

    if (c == '#' && PsiTreeUtil.getParentOfType(lookup.getPsiElement(), PsiDocComment.class) != null) {
      if (o instanceof PsiClass) {
        return Result.SELECT_ITEM_AND_FINISH_LOOKUP;
      }
    }
    if (c == '(' && PsiKeyword.RETURN.equals(item.getLookupString())) {
      return Result.HIDE_LOOKUP;
    }
    return null;
  }

}