rtextareabase.java~1~

具有不同语法高亮的编辑器实例

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	/**
	 * Returns the default caret color.
	 *
	 * @return The default caret color.
	 */
	public static final Color getDefaultCaretColor() {
		return DEFAULT_CARET_COLOR;
	}


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	/**
	 * Returns the "default" color for highlighting the current line.  Note
	 * that this color was chosen only because it looks nice (to me) against a
	 * white background.
	 *
	 * @return The default color for highlighting the current line.
	 */
	public static final Color getDefaultCurrentLineHighlightColor() {
		return DEFAULT_CURRENT_LINE_HIGHLIGHT_COLOR;
	}


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	/**
	 * Returns the default color for the margin line.
	 *
	 * @return The default margin line color.
	 * @see #getMarginLineColor
	 * @see #setMarginLineColor
	 */
	public static final Color getDefaultMarginLineColor() {
		return DEFAULT_MARGIN_LINE_COLOR;
	}


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	/**
	 * Returns the default margin line position.
	 *
	 * @return The default margin line position.
	 * @see #getMarginLinePosition
	 * @see #setMarginLinePosition
	 */
	public static final int getDefaultMarginLinePosition() {
		return DEFAULT_MARGIN_LINE_POSITION;
	}


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	/**
	 * Returns the default selection color for this text area.  This
	 * color was chosen because it's light and <code>RTextArea</code>
	 * does not change text color between selected/unselected text for
	 * contrast like regular <code>JTextArea</code>s do.
	 *
	 * @return The default selection color.
	 */
	public static Color getDefaultSelectionColor() {
		return DEFAULT_SELECTION_COLOR;
	}


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	/**
	 * Returns the default tab size, in spaces.
	 *
	 * @return The default tab size.
	 */
	public static final int getDefaultTabSize() {
		return DEFAULT_TAB_SIZE;
	}


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	/**
	 * Returns whether the current line highlight is faded.
	 *
	 * @return Whether the current line highlight is faded.
	 * @see #setFadeCurrentLineHighlight
	 */
	public boolean getFadeCurrentLineHighlight() {
		return fadeCurrentLineHighlight;
	}


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	/**
	 * Returns the offset of the last character of the line that the caret is
	 * on.
	 *
	 * @return The last offset of the line that the caret is currently on.
	 */
	public final int getLineEndOffsetOfCurrentLine() {
		try {
			return getLineEndOffset(getCaretLineNumber());
		} catch (BadLocationException ble) {
			/* Will never happen. */
			return 0;
		}
	}


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	/**
	 * Returns the height of a line of text in this text area.
	 *
	 * @return The height of a line of text.
	 */
	public int getLineHeight() {
		return getRowHeight();
	}


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	/**
	 * Returns the offset of the first character of the line that the caret is
	 * on.
	 *
	 * @return The first offset of the line that the caret is currently on.
	 */
	public final int getLineStartOffsetOfCurrentLine() {
		try {
			return getLineStartOffset(getCaretLineNumber());
		} catch (BadLocationException ble) {
			/* Will never happen. */
			return 0;
		}
	}


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	/**
	 * Returns the color used to paint the margin line.
	 *
	 * @return The margin line color.
	 * @see #setMarginLineColor
	 */
	public Color getMarginLineColor() {
		return marginLineColor;
	}


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	/**
	 * Returns the margin line position (in pixels) from the left-hand side of
	 * the text area.
	 *
	 * @return The margin line position.
	 * @see #getDefaultMarginLinePosition
	 * @see #setMarginLinePosition
	 */
	public int getMarginLinePixelLocation() {
		return marginLineX;
	}


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	/**
	 * Returns the margin line position (which is the number of 'm' widths in
	 * the current font the margin line is over).
	 *
	 * @return The margin line position.
	 * @see #getDefaultMarginLinePosition
	 * @see #setMarginLinePosition
	 */
	public int getMarginLinePosition() {
		return marginSizeInChars;
	}


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	/**
	 * Returns whether selection edges are rounded in this text area.
	 *
	 * @return Whether selection edges are rounded.
	 * @see #setRoundedSelectionEdges
	 */
	public boolean getRoundedSelectionEdges() {
		return roundedSelectionEdges;
	}


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	/**
	 * Returns whether or not tabs are emulated with spaces (i.e., "soft"
	 * tabs).
	 *
	 * @return <code>true</code> if tabs are emulated with spaces;
	 *         <code>false</code> if they aren't.
	 * @see #setTabsEmulated
	 */
	public boolean getTabsEmulated() {
		return tabsEmulatedWithSpaces;
	}


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	/**
	 * Determines the word closest to/at the given model position.
	 * Uses BreakIterator.getWordInstance() to actually get the words.
	 * 
	 * @param offs The offset in the document >= 0
	 * @return The word closest to/at that position.
	 * @exception BadLocationException if the offset is out of range
	 */
	public final String getWordAtOffset(int offs) throws BadLocationException {
		Document doc = getDocument();
		Element map = doc.getDefaultRootElement();
		int lineNumber = map.getElementIndex(offs);
		Element line = map.getElement(lineNumber);
		int lineStart = line.getStartOffset();
		int lineEnd = Math.min(line.getEndOffset(), doc.getLength());
	
		String s = doc.getText(lineStart, lineEnd - lineStart);
		if(s != null && s.length() > 0) {
			BreakIterator words = BreakIterator.getWordInstance();
			words.setText(s);
			int wordPosition = offs - lineStart;
			if(wordPosition >= words.last()) {
				wordPosition = words.last() - 1;
			} 
			//words.following(wordPosition);
			int end = lineStart + words.following(wordPosition);
			int start = lineStart + words.previous();
			return doc.getText(start, end-start);
		}
		return null;
	}


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	/**
	 * Returns whether or not the current line is highlighted.
	 *
	 * @return Whether or the current line is highlighted.
	 * @see #setCurrentLineHighlightEnabled
	 * @see #getCurrentLineHighlightColor
	 * @see #setCurrentLineHighlightColor
	 */
	public final boolean isCurrentLineHighlightEnabled() {
		return highlightCurrentLine;
	}


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	/**
	 * Returns whether or not the margin line is being painted.
	 *
	 * @return Whether or not the margin line is being painted.
	 * @see #setMarginLineEnabled
	 */
	public boolean isMarginLineEnabled() {
		return marginLineEnabled;
	}


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	/**
	 * Paints the text area.
	 *
	 * @param g The graphics context with which to paint.
	 */
	public void paintComponent(Graphics g) {

		//long startTime = System.currentTimeMillis();

		backgroundPainter.paint(g, getVisibleRect());

		// Paint the main part of the text area.
		TextUI ui = getUI();
		if (ui != null) {
			// Not allowed to modify g, so make a copy.
			Graphics scratchGraphics = g.create();
			try {
				ui.update(scratchGraphics, this);
			}
			finally {
				scratchGraphics.dispose();
			}
		}

		//long endTime = System.currentTimeMillis();
		//System.err.println(endTime-startTime);

	}


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	/**
	 * Updates the current line highlight location.
	 */
	protected void possiblyUpdateCurrentLineHighlightLocation() {

		int width = getWidth();
		int lineHeight = getLineHeight();
		int caretPos = getCaretPosition();

		// If we're wrapping lines we need to check the actual y-coordinate
		// of the caret, not just the line number, since a single logical
		// line can span multiple physical lines.
		if (getLineWrap()) {
			try {
				Rectangle temp = modelToView(caretPos);
				if (temp!=null)
					currentCaretY = temp.y;
			} catch (BadLocationException ble) {
				ble.printStackTrace(); // Should never happen.
			}
		}

		// No line wrap - we can simply check the line number (quicker).
		else {
			Document doc = getDocument();
			if (doc!=null) {
				Element map = doc.getDefaultRootElement();
				int caretLine = map.getElementIndex(caretPos);
				Rectangle alloc = ((RTextAreaUI)getUI()).
											getVisibleEditorRect();
				if (alloc!=null)
					currentCaretY = alloc.y + caretLine*lineHeight;
			}
		}

		// Repaint current line (to fill in entire highlight), and old line
		// (to erase entire old highlight) if necessary.
		repaint(0,currentCaretY, width,lineHeight);
		if (currentCaretY!=previousCaretY)
			repaint(0,previousCaretY, width,lineHeight);
		previousCaretY = currentCaretY;

	}


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	/**
	 * Overridden so we can tell when the text area is resized and update the
	 * current-line highlight, if necessary (i.e., if it is enabled and if
	 * lineWrap is enabled.
	 *
	 * @param e The component event about to be sent to all registered
	 *          <code>ComponentListener</code>s.
	 */
	protected void processComponentEvent(ComponentEvent e) {

		// In line wrap mode, resizing the text area means that the caret's
		// "line" could change - not to a different logical line, but a
		// different physical one.  So, here we force a repaint of the current
		// line's highlight if necessary.
		if (e.getID()==ComponentEvent.COMPONENT_RESIZED &&
				getLineWrap()==true && isCurrentLineHighlightEnabled()) {
			previousCaretY = -1;  // So we are sure to repaint.
			fireCaretUpdate(mouseListener);
		}

		super.processComponentEvent(e);

	}


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