tokenmarker.java

报表设计软件,很好的

package org.jfree.designer.text.jedit.syntax;

/*
 * TokenMarker.java - Generic token marker
 * Copyright (C) 1998, 1999 Slava Pestov
 *
 * You may use and modify this package for any purpose. Redistribution is
 * permitted, in both source and binary form, provided that this notice
 * remains intact in all source distributions of this package.
 */

import javax.swing.text.Segment;

/**
 * A token marker that splits lines of text into tokens. Each token carries a length field
 * and an indentification tag that can be mapped to a color for painting that token.<p>
 * <p/>
 * For performance reasons, the linked list of tokens is reused after each line is
 * tokenized. Therefore, the return value of <code>markTokens</code> should only be used
 * for immediate painting. Notably, it cannot be cached.
 *
 * @author Slava Pestov
 * @version $Id: TokenMarker.java,v 1.2 2004/04/20 18:54:52 taqua Exp $
 *          <p/>
 *          //@see com.efs.transfix.gui.components.jEditTextArea.Token
 */
public abstract class TokenMarker
{
  /**
   * A wrapper for the lower-level <code>markTokensImpl</code> method that is called to
   * split a line up into tokens.
   *
   * @param line      The line
   * @param lineIndex The line number
   */
  public final Token markTokens (final Segment line, final int lineIndex)
  {
    if (lineIndex >= length)
    {
      throw new IllegalArgumentException("Tokenizing invalid line: "
              + lineIndex);
    }

    lastToken = null;

    final LineInfo info = lineInfo[lineIndex];
    final LineInfo prev;
    if (lineIndex == 0)
    {
      prev = null;
    }
    else
    {
      prev = lineInfo[lineIndex - 1];
    }

    final byte oldToken = info.token;
    final byte token = markTokensImpl(prev == null ?
            Token.NULL : prev.token, line, lineIndex);

    info.token = token;

    /*
     * This is a foul hack. It stops nextLineRequested
     * from being cleared if the same line is marked twice.
     *
     * Why is this necessary? It's all JEditTextArea's fault.
     * When something is inserted into the text, firing a
     * document event, the insertUpdate() method shifts the
     * caret (if necessary) by the amount inserted.
     *
     * All caret movement is handled by the select() method,
     * which eventually pipes the new position to scrollTo()
     * and calls repaint().
     *
     * Note that at this point in time, the new line hasn't
     * yet been painted; the caret is moved first.
     *
     * scrollTo() calls offsetToX(), which tokenizes the line
     * unless it is being called on the last line painted
     * (in which case it uses the text area's painter cached
     * token list). What scrollTo() does next is irrelevant.
     *
     * After scrollTo() has done it's job, repaint() is
     * called, and eventually we end up in paintLine(), whose
     * job is to paint the changed line. It, too, calls
     * markTokens().
     *
     * The problem was that if the line started a multiline
     * token, the first markTokens() (done in offsetToX())
     * would set nextLineRequested (because the line end
     * token had changed) but the second would clear it
     * (because the line was the same that time) and therefore
     * paintLine() would never know that it needed to repaint
     * subsequent lines.
     *
     * This bug took me ages to track down, that's why I wrote
     * all the relevant info down so that others wouldn't
     * duplicate it.
     */
    if (!(lastLine == lineIndex && nextLineRequested))
    {
      nextLineRequested = (oldToken != token);
    }

    lastLine = lineIndex;

    addToken(0, Token.END);

    return firstToken;
  }

  /**
   * An abstract method that splits a line up into tokens. It should parse the line, and
   * call <code>addToken()</code> to add syntax tokens to the token list. Then, it should
   * return the initial token type for the next line.<p>
   * <p/>
   * For example if the current line contains the start of a multiline comment that
   * doesn't end on that line, this method should return the comment token type so that it
   * continues on the next line.
   *
   * @param token     The initial token type for this line
   * @param line      The line to be tokenized
   * @param lineIndex The index of the line in the document, starting at 0
   * @return The initial token type for the next line
   */
  protected abstract byte markTokensImpl (byte token, Segment line,
                                          int lineIndex);

  /**
   * Returns if the token marker supports tokens that span multiple lines. If this is
   * true, the object using this token marker is required to pass all lines in the
   * document to the <code>markTokens()</code> method (in turn).<p>
   * <p/>
   * The default implementation returns true; it should be overridden to return false on
   * simpler token markers for increased speed.
   */
  public final boolean supportsMultilineTokens ()
  {
    return true;
  }

  /**
   * Informs the token marker that lines have been inserted into the document. This
   * inserts a gap in the <code>lineInfo</code> array.
   *
   * @param index The first line number
   * @param lines The number of lines
   */
  public final void insertLines (final int index, final int lines)
  {
    if (lines <= 0)
    {
      return;
    }
    length += lines;
    ensureCapacity(length);
    final int len = index + lines;
    System.arraycopy(lineInfo, index, lineInfo, len,
            lineInfo.length - len);

    for (int i = index + lines - 1; i >= index; i--)
    {
      lineInfo[i] = new LineInfo();
    }
  }

  /**
   * Informs the token marker that line have been deleted from the document. This removes
   * the lines in question from the <code>lineInfo</code> array.
   *
   * @param index The first line number
   * @param lines The number of lines
   */
  public final void deleteLines (final int index, final int lines)
  {
    if (lines <= 0)
    {
      return;
    }
    final int len = index + lines;
    length -= lines;
    System.arraycopy(lineInfo, len, lineInfo,
            index, lineInfo.length - len);
  }

  /**
   * Returns the number of lines in this token marker.
   */
  public final int getLineCount ()
  {
    return length;
  }

  /**
   * Returns true if the next line should be repainted. This will return true after a line
   * has been tokenized that starts a multiline token that continues onto the next line.
   */
  public final boolean isNextLineRequested ()
  {
    return nextLineRequested;
  }

  // protected members

  /**
   * The first token in the list. This should be used as the return value from
   * <code>markTokens()</code>.
   */
  private Token firstToken;

  /**
   * The last token in the list. New tokens are added here. This should be set to null
   * before a new line is to be tokenized.
   */
  private Token lastToken;

  /**
   * An array for storing information about lines. It is enlarged and shrunk automatically
   * by the <code>insertLines()</code> and <code>deleteLines()</code> methods.
   */
  private LineInfo[] lineInfo;

  /**
   * The number of lines in the model being tokenized. This can be less than the length of
   * the <code>lineInfo</code> array.
   */
  private int length;

  /**
   * The last tokenized line.
   */
  private int lastLine;

  /**
   * True if the next line should be painted.
   */
  private boolean nextLineRequested;

  /**
   * Creates a new <code>TokenMarker</code>. This DOES NOT create a lineInfo array; an
   * initial call to <code>insertLines()</code> does that.
   */
  protected TokenMarker ()
  {
    lastLine = -1;
  }

  /**
   * Ensures that the <code>lineInfo</code> array can contain the specified index. This
   * enlarges it if necessary. No action is taken if the array is large enough
   * already.<p>
   * <p/>
   * It should be unnecessary to call this under normal circumstances;
   * <code>insertLine()</code> should take care of enlarging the line info array
   * automatically.
   *
   * @param index The array index
   */
  private void ensureCapacity (final int index)
  {
    if (lineInfo == null)
    {
      lineInfo = new LineInfo[index + 1];
    }
    else if (lineInfo.length <= index)
    {
      final LineInfo[] lineInfoN = new LineInfo[(index + 1) * 2];
      System.arraycopy(lineInfo, 0, lineInfoN, 0,
              lineInfo.length);
      lineInfo = lineInfoN;
    }
  }

  /**
   * Adds a token to the token list.
   *
   * @param length The length of the token
   * @param id     The id of the token
   */
  protected final void addToken (final int length, final byte id)
  {
    if (id >= Token.INTERNAL_FIRST && id <= Token.INTERNAL_LAST)
    {
      throw new InternalError("Invalid id: " + id);
    }

    if (length == 0 && id != Token.END)
    {
      return;
    }

    if (firstToken == null)
    {
      firstToken = new Token(length, id);
      lastToken = firstToken;
    }
    else if (lastToken == null)
    {
      lastToken = firstToken;
      firstToken.length = length;
      firstToken.id = id;
    }
    else if (lastToken.next == null)
    {
      lastToken.next = new Token(length, id);
      lastToken = lastToken.next;
    }
    else
    {
      lastToken = lastToken.next;
      lastToken.length = length;
      lastToken.id = id;
    }
  }

  /**
   * Inner class for storing information about tokenized lines.
   */
  public final class LineInfo
  {
    /**
     * Creates a new LineInfo object with token = Token.NULL and obj = null.
     */
    private LineInfo ()
    {
    }

    /**
     * Creates a new LineInfo object with the specified parameters.
     */
    public LineInfo (final byte token, final Object obj)
    {
      this.token = token;
      this.obj = obj;
    }

    /**
     * The id of the last token of the line.
     */
    public byte token;

    /**
     * This is for use by the token marker implementations themselves. It can be used to
     * store anything that is an object and that needs to exist on a per-line basis.
     */
    public Object obj;
  }
}