java/java-impl/src/com/intellij/codeInsight/editorActions/JavaBackspaceHandler.java

   1 /*
   2  * Copyright 2000-2009 JetBrains s.r.o.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 package com.intellij.codeInsight.editorActions;
  17
  18 import com.intellij.openapi.editor.Editor;
  19 import com.intellij.openapi.editor.ex.EditorEx;
  20 import com.intellij.openapi.editor.highlighter.HighlighterIterator;
  21 import com.intellij.psi.JavaTokenType;
  22 import com.intellij.psi.PsiFile;
  23 import com.intellij.psi.PsiJavaFile;
  24 import com.intellij.psi.tree.IElementType;
  25 import com.intellij.psi.util.PsiUtil;
  26
  27 public class JavaBackspaceHandler extends BackspaceHandlerDelegate {
  28   private boolean myToDeleteGt;
  29
  30   public void beforeCharDeleted(char c, PsiFile file, Editor editor) {
  31     int offset = editor.getCaretModel().getOffset() - 1;
  32     myToDeleteGt = c =='<' &&
  33                         file instanceof PsiJavaFile &&
  34                         PsiUtil.isLanguageLevel5OrHigher(file)
  35                         && JavaTypedHandler.isAfterClassLikeIdentifierOrDot(offset, editor);
  36   }
  37
  38   public boolean charDeleted(final char c, final PsiFile file, final Editor editor) {
  39     int offset = editor.getCaretModel().getOffset();
  40     final CharSequence chars = editor.getDocument().getCharsSequence();
  41     if (editor.getDocument().getTextLength() <= offset) return false; //virtual space after end of file
  42
  43     char c1 = chars.charAt(offset);
  44     if (c == '<' && myToDeleteGt) {
  45       if (c1 != '>') return true;
  46       handleLTDeletion(editor, offset);
  47       return true;
  48     }
  49     return false;
  50   }
  51
  52   private static void handleLTDeletion(final Editor editor, final int offset) {
  53     HighlighterIterator iterator = ((EditorEx)editor).getHighlighter().createIterator(offset);
  54     while (iterator.getStart() > 0 && !JavaTypedHandlerUtil.isTokenInvalidInsideReference(iterator.getTokenType())) {
  55       iterator.retreat();
  56     }
  57
  58     if (JavaTypedHandlerUtil.isTokenInvalidInsideReference(iterator.getTokenType())) iterator.advance();
  59
  60     int balance = 0;
  61     while (!iterator.atEnd() && balance >= 0) {
  62       final IElementType tokenType = iterator.getTokenType();
  63       if (tokenType == JavaTokenType.LT) {
  64         balance++;
  65       }
  66       else if (tokenType == JavaTokenType.GT) {
  67         balance--;
  68       }
  69       else if (JavaTypedHandlerUtil.isTokenInvalidInsideReference(tokenType)) {
  70         break;
  71       }
  72
  73       iterator.advance();
  74     }
  75
  76     if (balance < 0) {
  77       editor.getDocument().deleteString(offset, offset + 1);
  78     }
  79   }
  80 }