Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2005 IBM Corporation and others. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ // copied directly from org.eclipse.jface.internal.text.link.contentassist.HTML2TextReader; package com.aptana.ide.editors.unified.utils; import java.io.IOException; import java.io.PushbackReader; import java.io.Reader; import java.util.HashMap; import java.util.HashSet; import java.util.Map; import java.util.Set; import org.eclipse.jface.resource.ColorRegistry; import org.eclipse.jface.resource.JFaceResources; import org.eclipse.jface.text.TextPresentation; import org.eclipse.swt.SWT; import org.eclipse.swt.custom.StyleRange; import org.eclipse.swt.graphics.Color; import org.eclipse.swt.graphics.RGB; import org.eclipse.swt.widgets.Display; import com.aptana.ide.core.StringUtils; /** * Reads the text contents from a reader of HTML contents and translates * the tags or cut them out. */ class HTML2TextReader extends SubstitutionTextReader { private static final String EMPTY_STRING = StringUtils.EMPTY; private static final Map<String, String> fgEntityLookup; private static final Set<String> fgTags; static { fgTags = new HashSet<String>(); fgTags.add("b"); //$NON-NLS-1$ fgTags.add("i"); //$NON-NLS-1$ fgTags.add("br"); //$NON-NLS-1$ fgTags.add("h2"); //$NON-NLS-1$ fgTags.add("h3"); //$NON-NLS-1$ fgTags.add("h5"); //$NON-NLS-1$ fgTags.add("p"); //$NON-NLS-1$ fgTags.add("dl"); //$NON-NLS-1$ fgTags.add("dt"); //$NON-NLS-1$ fgTags.add("dd"); //$NON-NLS-1$ fgTags.add("li"); //$NON-NLS-1$ fgTags.add("ul"); //$NON-NLS-1$ fgTags.add("pre"); //$NON-NLS-1$ fgTags.add("code"); //$NON-NLS-1$ fgTags.add("script"); //$NON-NLS-1$ fgTags.add("property"); //$NON-NLS-1$ fgTags.add("var"); //$NON-NLS-1$ fgTags.add("method"); //$NON-NLS-1$ fgTags.add("specification"); //$NON-NLS-1$ fgEntityLookup = new HashMap<String, String>(8); fgEntityLookup.put("lt", "<"); //$NON-NLS-1$ //$NON-NLS-2$ fgEntityLookup.put("gt", ">"); //$NON-NLS-1$ //$NON-NLS-2$ fgEntityLookup.put("nbsp", " "); //$NON-NLS-1$ //$NON-NLS-2$ fgEntityLookup.put("amp", "&"); //$NON-NLS-1$ //$NON-NLS-2$ fgEntityLookup.put("circ", "^"); //$NON-NLS-1$ //$NON-NLS-2$ fgEntityLookup.put("tilde", "~"); //$NON-NLS-2$ //$NON-NLS-1$ fgEntityLookup.put("quot", "\""); //$NON-NLS-1$ //$NON-NLS-2$ fgEntityLookup.put("rarr", "?"); //$NON-NLS-1$ //$NON-NLS-2$ } private int fCounter = 0; private TextPresentation fTextPresentation; private int fBold = 0; private int fItalic = 0; private int fHeader = 0; private int fCode = 0; private int fPre = 0; private int fStartOffset = -1; private int fStartItalicOffset = -1; private int fStartHeaderOffset = -1; private int fStartCodeOffset = -1; private int fStartPreOffset = -1; private boolean fIsPreformattedText = false; private String fPreviousTag = StringUtils.EMPTY; private Color fLinkColor = null; private Color fPreColor = null; /** * Transforms the HTML text from the reader to formatted text. * * @param reader the reader * @param presentation If not <code>null</code>, formattings will be applied to * the presentation. * @param display */ public HTML2TextReader(Reader reader, TextPresentation presentation, Display display) { super(new PushbackReader(reader)); fTextPresentation = presentation; RGB blackColor = new RGB(0, 0, 0); RGB linkColor = new RGB(93, 117, 215); RGB preColor = new RGB(204, 153, 51); ColorRegistry cm = JFaceResources.getColorRegistry(); cm.put("black", blackColor); //$NON-NLS-1$ cm.put("link", linkColor); //$NON-NLS-1$ cm.put("pre", preColor); //$NON-NLS-1$ fLinkColor = cm.get("link"); //$NON-NLS-1$ fPreColor = cm.get("pre"); //$NON-NLS-1$ } /** * @see java.io.Reader#read() */ public int read() throws IOException { int c = super.read(); if (c != -1) { ++fCounter; } return c; } /** * startBold */ protected void startBold() { if (fBold == 0) { fStartOffset = fCounter; } ++fBold; } /** * startItalic */ protected void startItalic() { if (fItalic == 0) { fStartItalicOffset = fCounter; } ++fItalic; } /** * startHeader */ protected void startHeader() { if (fHeader == 0) { fStartHeaderOffset = fCounter; } ++fHeader; } /** * startCode */ protected void startCode() { if (fCode == 0) { fStartCodeOffset = fCounter; } ++fCode; } /** * startPre */ protected void startPre() { if (fPre == 0) { fStartPreOffset = fCounter; } ++fPre; } /** * startPreformattedText */ protected void startPreformattedText() { fIsPreformattedText = true; setSkipWhitespace(false); } /** * stopPreformattedText */ protected void stopPreformattedText() { fIsPreformattedText = false; setSkipWhitespace(true); } /** * stopBold */ protected void stopBold() { --fBold; if (fBold == 0) { if (fTextPresentation != null) { fTextPresentation .addStyleRange(new StyleRange(fStartOffset, fCounter - fStartOffset, null, null, SWT.BOLD)); } fStartOffset = -1; } } /** * stopItalic */ protected void stopItalic() { --fItalic; if (fItalic == 0) { if (fTextPresentation != null) { fTextPresentation.addStyleRange( new StyleRange(fStartItalicOffset, fCounter - fStartItalicOffset, null, null, SWT.ITALIC)); } fStartItalicOffset = -1; } } /** * stopHeader */ protected void stopHeader() { --fHeader; if (fHeader == 0) { if (fTextPresentation != null) { fTextPresentation.addStyleRange( new StyleRange(fStartHeaderOffset, fCounter - fStartHeaderOffset, null, null, SWT.BOLD)); } fStartHeaderOffset = -1; } } /** * stopCode */ protected void stopCode() { --fCode; if (fHeader == 0) { if (fTextPresentation != null) { fTextPresentation.addStyleRange( new StyleRange(fStartCodeOffset, fCounter - fStartCodeOffset, fLinkColor, null, SWT.BOLD)); } fStartCodeOffset = -1; } } /** * stopPre */ protected void stopPre() { --fPre; if (fPre == 0) { if (fTextPresentation != null) { fTextPresentation.addStyleRange( new StyleRange(fStartPreOffset, fCounter - fStartPreOffset, fPreColor, null, SWT.NORMAL)); } fStartCodeOffset = -1; } } /** * @see com.aptana.ide.editors.unified.utils.SubstitutionTextReader#computeSubstitution(int) */ protected String computeSubstitution(int c) throws IOException { if (c == '<') { return processHTMLTag(); } else if (c == '&') { return processEntity(); } else if (fIsPreformattedText) { return processPreformattedText(c); } return null; } private String html2Text(String html) { if (html == null || html.length() == 0) { return EMPTY_STRING; } String tag = html; String lastTag = fPreviousTag; fPreviousTag = tag; if ('/' == tag.charAt(0)) { tag = tag.substring(1); } if (!fgTags.contains(tag)) { return EMPTY_STRING; } if ("pre".equals(html)) { //$NON-NLS-1$ startPreformattedText(); startPre(); return LINE_DELIM; } if ("/pre".equals(html)) { //$NON-NLS-1$ stopPreformattedText(); stopPre(); return LINE_DELIM; } if ("script".equals(html)) { //$NON-NLS-1$ return "<script>"; //$NON-NLS-1$ } if ("/script".equals(html)) { //$NON-NLS-1$ return "</script>"; //$NON-NLS-1$ } if (fIsPreformattedText) { return EMPTY_STRING; } if ("b".equals(html)) { //$NON-NLS-1$ startBold(); return EMPTY_STRING; } if ("code".equals(html) || "property".equals(html) || "var".equals(html) //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ || "method".equals(html) || "specification".equals(html)) { //$NON-NLS-1$ //$NON-NLS-2$ startCode(); return EMPTY_STRING; } if ("i".equals(html)) { //$NON-NLS-1$ startItalic(); return EMPTY_STRING; } if ("h5".equals(html) || "dt".equals(html)) { //$NON-NLS-1$ //$NON-NLS-2$ startBold(); return EMPTY_STRING; } if ("h2".equals(html)) { //$NON-NLS-1$ startBold(); if ("/p".equals(lastTag) || "/pre".equals(lastTag)) //$NON-NLS-1$ //$NON-NLS-2$ { return LINE_DELIM; } else { return LINE_DELIM + LINE_DELIM; } } if ("h3".equals(html)) { //$NON-NLS-1$ startHeader(); if ("/p".equals(lastTag) || "/pre".equals(lastTag)) //$NON-NLS-1$ //$NON-NLS-2$ { return LINE_DELIM; } else { return LINE_DELIM + LINE_DELIM; } } if ("dl".equals(html)) //$NON-NLS-1$ { return LINE_DELIM; } if ("dd".equals(html)) //$NON-NLS-1$ { return "\t"; //$NON-NLS-1$ } if ("li".equals(html)) { //$NON-NLS-1$ // FIXME: this hard-coded prefix does not work for RTL languages, see https://bugs.eclipse.org/bugs/show_bug.cgi?id=91682 return LINE_DELIM + "\t"; //$NON-NLS-1$ } if ("/b".equals(html)) { //$NON-NLS-1$ stopBold(); return EMPTY_STRING; } if ("/code".equals(html) || "/property".equals(html) || "/var".equals(html) //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ || "/method".equals(html) || "/specification".equals(html)) { //$NON-NLS-1$ //$NON-NLS-2$ stopCode(); return EMPTY_STRING; } if ("/i".equals(html)) { //$NON-NLS-1$ stopItalic(); return EMPTY_STRING; } if ("p".equals(html)) { //$NON-NLS-1$ return LINE_DELIM; } if ("br".equals(html)) //$NON-NLS-1$ { return LINE_DELIM; } if ("/p".equals(html)) { //$NON-NLS-1$ if ("/pre".equals(lastTag)) //$NON-NLS-1$ { return EMPTY_STRING; } else { return LINE_DELIM; } } if ("/h5".equals(html) || "/dt".equals(html)) { //$NON-NLS-1$ //$NON-NLS-2$ stopBold(); return LINE_DELIM; } if ("/h2".equals(html)) { //$NON-NLS-1$ stopBold(); return LINE_DELIM; } if ("/h3".equals(html)) { //$NON-NLS-1$ stopHeader(); return EMPTY_STRING; } if ("/dd".equals(html)) //$NON-NLS-1$ { return LINE_DELIM; } return EMPTY_STRING; } /* * A '<' has been read. Process a HTML tag */ private String processHTMLTag() throws IOException { StringBuffer buf = new StringBuffer(); int ch; do { ch = nextChar(); while (ch != -1 && ch != '>') { buf.append(Character.toLowerCase((char) ch)); ch = nextChar(); if (ch == '"') { buf.append(Character.toLowerCase((char) ch)); ch = nextChar(); while (ch != -1 && ch != '"') { buf.append(Character.toLowerCase((char) ch)); ch = nextChar(); } } if (ch == '<') { unread(ch); return '<' + buf.toString(); } } if (ch == -1) { return null; } int tagLen = buf.length(); // needs special treatment for comments if ((tagLen >= 3 && "!--".equals(buf.substring(0, 3))) //$NON-NLS-1$ && !(tagLen >= 5 && "--".equals(buf.substring(tagLen - 2)))) { //$NON-NLS-1$ // unfinished comment buf.append(ch); } else { break; } } while (true); return html2Text(buf.toString()); } private String processPreformattedText(int c) { // [IM] Line delimiter is two chars on windows. We only appear to need to do // this step on windows. if ((c == '\r' || c == '\n') && LINE_DELIM.length() == 2) { fCounter++; } return null; } private void unread(int ch) throws IOException { ((PushbackReader) getReader()).unread(ch); } /** * entity2Text * * @param symbol * @return String */ protected String entity2Text(String symbol) { if (symbol.length() > 1 && symbol.charAt(0) == '#') { int ch; try { if (symbol.charAt(1) == 'x') { ch = Integer.parseInt(symbol.substring(2), 16); } else { ch = Integer.parseInt(symbol.substring(1), 10); } return EMPTY_STRING + (char) ch; } catch (NumberFormatException e) { } } else { String str = fgEntityLookup.get(symbol); if (str != null) { return str; } } return "&" + symbol; // not found //$NON-NLS-1$ } /* * A '&' has been read. Process a entity */ private String processEntity() throws IOException { StringBuffer buf = new StringBuffer(); int ch = nextChar(); while (Character.isLetterOrDigit((char) ch) || ch == '#') { buf.append((char) ch); ch = nextChar(); } if (ch == ';') { return entity2Text(buf.toString()); } buf.insert(0, '&'); if (ch != -1) { buf.append((char) ch); } return buf.toString(); } }