Java tutorial
/* * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.swing.text; import java.util.Vector; /** * A plain document that maintains no character attributes. The * default element structure for this document is a map of the lines in * the text. The Element returned by getDefaultRootElement is * a map of the lines, and each child element represents a line. * This model does not maintain any character level attributes, * but each line can be tagged with an arbitrary set of attributes. * Line to offset, and offset to line translations can be quickly * performed using the default root element. The structure information * of the DocumentEvent's fired by edits will indicate the line * structure changes. * <p> * The default content storage management is performed by a * gapped buffer implementation (GapContent). It supports * editing reasonably large documents with good efficiency when * the edits are contiguous or clustered, as is typical. * <p> * <strong>Warning:</strong> * Serialized objects of this class will not be compatible with * future Swing releases. The current serialization support is * appropriate for short term storage or RMI between applications running * the same version of Swing. As of 1.4, support for long term storage * of all JavaBeans™ * has been added to the <code>java.beans</code> package. * Please see {@link java.beans.XMLEncoder}. * * @author Timothy Prinzing * @see Document * @see AbstractDocument */ @SuppressWarnings("serial") // Same-version serialization only public class PlainDocument extends AbstractDocument { /** * Name of the attribute that specifies the tab * size for tabs contained in the content. The * type for the value is Integer. */ public static final String tabSizeAttribute = "tabSize"; /** * Name of the attribute that specifies the maximum * length of a line, if there is a maximum length. * The type for the value is Integer. */ public static final String lineLimitAttribute = "lineLimit"; /** * Constructs a plain text document. A default model using * <code>GapContent</code> is constructed and set. */ public PlainDocument() { this(new GapContent()); } /** * Constructs a plain text document. A default root element is created, * and the tab size set to 8. * * @param c the container for the content */ public PlainDocument(Content c) { super(c); putProperty(tabSizeAttribute, Integer.valueOf(8)); defaultRoot = createDefaultRoot(); } /** * Inserts some content into the document. * Inserting content causes a write lock to be held while the * actual changes are taking place, followed by notification * to the observers on the thread that grabbed the write lock. * <p> * This method is thread safe, although most Swing methods * are not. Please see * <A HREF="https://docs.oracle.com/javase/tutorial/uiswing/concurrency/index.html">Concurrency * in Swing</A> for more information. * * @param offs the starting offset >= 0 * @param str the string to insert; does nothing with null/empty strings * @param a the attributes for the inserted content * @exception BadLocationException the given insert position is not a valid * position within the document * @see Document#insertString */ public void insertString(int offs, String str, AttributeSet a) throws BadLocationException { // fields don't want to have multiple lines. We may provide a field-specific // model in the future in which case the filtering logic here will no longer // be needed. Object filterNewlines = getProperty("filterNewlines"); if ((filterNewlines instanceof Boolean) && filterNewlines.equals(Boolean.TRUE)) { if ((str != null) && (str.indexOf('\n') >= 0)) { StringBuilder filtered = new StringBuilder(str); int n = filtered.length(); for (int i = 0; i < n; i++) { if (filtered.charAt(i) == '\n') { filtered.setCharAt(i, ' '); } } str = filtered.toString(); } } super.insertString(offs, str, a); } /** * Gets the default root element for the document model. * * @return the root * @see Document#getDefaultRootElement */ public Element getDefaultRootElement() { return defaultRoot; } /** * Creates the root element to be used to represent the * default document structure. * * @return the element base */ protected AbstractElement createDefaultRoot() { BranchElement map = (BranchElement) createBranchElement(null, null); Element line = createLeafElement(map, null, 0, 1); Element[] lines = new Element[1]; lines[0] = line; map.replace(0, 0, lines); return map; } /** * Get the paragraph element containing the given position. Since this * document only models lines, it returns the line instead. */ public Element getParagraphElement(int pos) { Element lineMap = getDefaultRootElement(); return lineMap.getElement(lineMap.getElementIndex(pos)); } /** * Updates document structure as a result of text insertion. This * will happen within a write lock. Since this document simply * maps out lines, we refresh the line map. * * @param chng the change event describing the dit * @param attr the set of attributes for the inserted text */ protected void insertUpdate(DefaultDocumentEvent chng, AttributeSet attr) { removed.removeAllElements(); added.removeAllElements(); BranchElement lineMap = (BranchElement) getDefaultRootElement(); int offset = chng.getOffset(); int length = chng.getLength(); if (offset > 0) { offset -= 1; length += 1; } int index = lineMap.getElementIndex(offset); Element rmCandidate = lineMap.getElement(index); int rmOffs0 = rmCandidate.getStartOffset(); int rmOffs1 = rmCandidate.getEndOffset(); int lastOffset = rmOffs0; try { if (s == null) { s = new Segment(); } getContent().getChars(offset, length, s); boolean hasBreaks = false; for (int i = 0; i < length; i++) { char c = s.array[s.offset + i]; if (c == '\n') { int breakOffset = offset + i + 1; added.addElement(createLeafElement(lineMap, null, lastOffset, breakOffset)); lastOffset = breakOffset; hasBreaks = true; } } if (hasBreaks) { removed.addElement(rmCandidate); if ((offset + length == rmOffs1) && (lastOffset != rmOffs1) && ((index + 1) < lineMap.getElementCount())) { Element e = lineMap.getElement(index + 1); removed.addElement(e); rmOffs1 = e.getEndOffset(); } if (lastOffset < rmOffs1) { added.addElement(createLeafElement(lineMap, null, lastOffset, rmOffs1)); } Element[] aelems = new Element[added.size()]; added.copyInto(aelems); Element[] relems = new Element[removed.size()]; removed.copyInto(relems); ElementEdit ee = new ElementEdit(lineMap, index, relems, aelems); chng.addEdit(ee); lineMap.replace(index, relems.length, aelems); } if (Utilities.isComposedTextAttributeDefined(attr)) { insertComposedTextUpdate(chng, attr); } } catch (BadLocationException e) { throw new Error("Internal error: " + e.toString()); } super.insertUpdate(chng, attr); } /** * Updates any document structure as a result of text removal. * This will happen within a write lock. Since the structure * represents a line map, this just checks to see if the * removal spans lines. If it does, the two lines outside * of the removal area are joined together. * * @param chng the change event describing the edit */ protected void removeUpdate(DefaultDocumentEvent chng) { removed.removeAllElements(); BranchElement map = (BranchElement) getDefaultRootElement(); int offset = chng.getOffset(); int length = chng.getLength(); int line0 = map.getElementIndex(offset); int line1 = map.getElementIndex(offset + length); if (line0 != line1) { // a line was removed for (int i = line0; i <= line1; i++) { removed.addElement(map.getElement(i)); } int p0 = map.getElement(line0).getStartOffset(); int p1 = map.getElement(line1).getEndOffset(); Element[] aelems = new Element[1]; aelems[0] = createLeafElement(map, null, p0, p1); Element[] relems = new Element[removed.size()]; removed.copyInto(relems); ElementEdit ee = new ElementEdit(map, line0, relems, aelems); chng.addEdit(ee); map.replace(line0, relems.length, aelems); } else { //Check for the composed text element Element line = map.getElement(line0); if (!line.isLeaf()) { Element leaf = line.getElement(line.getElementIndex(offset)); if (Utilities.isComposedTextElement(leaf)) { Element[] aelem = new Element[1]; aelem[0] = createLeafElement(map, null, line.getStartOffset(), line.getEndOffset()); Element[] relem = new Element[1]; relem[0] = line; ElementEdit ee = new ElementEdit(map, line0, relem, aelem); chng.addEdit(ee); map.replace(line0, 1, aelem); } } } super.removeUpdate(chng); } // // Inserts the composed text of an input method. The line element // where the composed text is inserted into becomes an branch element // which contains leaf elements of the composed text and the text // backing store. // private void insertComposedTextUpdate(DefaultDocumentEvent chng, AttributeSet attr) { added.removeAllElements(); BranchElement lineMap = (BranchElement) getDefaultRootElement(); int offset = chng.getOffset(); int length = chng.getLength(); int index = lineMap.getElementIndex(offset); Element elem = lineMap.getElement(index); int elemStart = elem.getStartOffset(); int elemEnd = elem.getEndOffset(); BranchElement[] abelem = new BranchElement[1]; abelem[0] = (BranchElement) createBranchElement(lineMap, null); Element[] relem = new Element[1]; relem[0] = elem; if (elemStart != offset) added.addElement(createLeafElement(abelem[0], null, elemStart, offset)); added.addElement(createLeafElement(abelem[0], attr, offset, offset + length)); if (elemEnd != offset + length) added.addElement(createLeafElement(abelem[0], null, offset + length, elemEnd)); Element[] alelem = new Element[added.size()]; added.copyInto(alelem); ElementEdit ee = new ElementEdit(lineMap, index, relem, abelem); chng.addEdit(ee); abelem[0].replace(0, 0, alelem); lineMap.replace(index, 1, abelem); } private AbstractElement defaultRoot; private Vector<Element> added = new Vector<Element>(); private Vector<Element> removed = new Vector<Element>(); private transient Segment s; }