org.eclipse.jdt.core/formatter/org/eclipse/jdt/internal/formatter/comment/MultiCommentLine.java - aspectj/org.aspectj.shadows - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2004 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
  *******************************************************************************/

 package org.eclipse.jdt.internal.formatter.comment;

 import java.util.HashSet;
 import java.util.Set;

 import org.eclipse.jface.text.IRegion;
 import org.eclipse.jface.text.Region;

 /**
  * Multi-line comment line in a comment region.
  *
  * @since 3.0
  */
 public class MultiCommentLine extends CommentLine implements ICommentAttributes, IHtmlTagDelimiters, IJavaDocTagConstants {

 	/** Line prefix of multi-line comment content lines */
 	public static final String MULTI_COMMENT_CONTENT_PREFIX= " * "; //$NON-NLS-1$

 	/** Line prefix of multi-line comment end lines */
 	public static final String MULTI_COMMENT_END_PREFIX= " */"; //$NON-NLS-1$

 	/** Line prefix of multi-line comment content lines */
 	public static final String MULTI_COMMENT_START_PREFIX= "/* "; //$NON-NLS-1$

 	/** The indentation reference of this line */
 	private String fReferenceIndentation= ""; //$NON-NLS-1$

 	/** The javadoc tag lookup. */
 	private static final Set fgTagLookup;

 	static {
 		fgTagLookup= new HashSet();
 		for (int i= 0; i < JAVADOC_BREAK_TAGS.length; i++) {
 			fgTagLookup.add(JAVADOC_BREAK_TAGS[i]);
 		}
 		for (int i= 0; i < JAVADOC_SINGLE_BREAK_TAG.length; i++) {
 			fgTagLookup.add(JAVADOC_SINGLE_BREAK_TAG[i]);
 		}
 		for (int i= 0; i < JAVADOC_CODE_TAGS.length; i++) {
 			fgTagLookup.add(JAVADOC_CODE_TAGS[i]);
 		}
 		for (int i= 0; i < JAVADOC_IMMUTABLE_TAGS.length; i++) {
 			fgTagLookup.add(JAVADOC_IMMUTABLE_TAGS[i]);
 		}
 		for (int i= 0; i < JAVADOC_NEWLINE_TAGS.length; i++) {
 			fgTagLookup.add(JAVADOC_NEWLINE_TAGS[i]);
 		}
 		for (int i= 0; i < JAVADOC_SEPARATOR_TAGS.length; i++) {
 			fgTagLookup.add(JAVADOC_SEPARATOR_TAGS[i]);
 		}
 	}

 	/**
 	 * Creates a new multi-line comment line.
 	 *
 	 * @param region comment region to create the line for
 	 */
 	protected MultiCommentLine(final CommentRegion region) {
 		super(region);
 	}

 	/*
 	 * @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#adapt(org.eclipse.jdt.internal.corext.text.comment.CommentLine)
 	 */
 	protected void adapt(final CommentLine previous) {

 		if (!hasAttribute(COMMENT_ROOT) && !hasAttribute(COMMENT_PARAMETER) && !previous.hasAttribute(COMMENT_BLANKLINE))
 			fReferenceIndentation= previous.getIndentationReference();
 	}

 	/*
 	 * @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#append(org.eclipse.jdt.internal.corext.text.comment.CommentRange)
 	 */
 	protected void append(final CommentRange range) {

 		final MultiCommentRegion parent= (MultiCommentRegion)getParent();

 		if (range.hasAttribute(COMMENT_PARAMETER))
 			setAttribute(COMMENT_PARAMETER);
 		else if (range.hasAttribute(COMMENT_ROOT))
 			setAttribute(COMMENT_ROOT);
 		else if (range.hasAttribute(COMMENT_BLANKLINE))
 			setAttribute(COMMENT_BLANKLINE);

 		final int ranges= getSize();
 		if (ranges == 1) {

 			if (parent.isIndentRoots()) {

 				final CommentRange first= getFirst();
 				final String common= parent.getText(first.getOffset(), first.getLength()) + CommentRegion.COMMENT_RANGE_DELIMITER;

 				if (hasAttribute(COMMENT_ROOT))
 					fReferenceIndentation= common;
 				else if (hasAttribute(COMMENT_PARAMETER)) {
 					if (parent.isIndentDescriptions())
 						fReferenceIndentation= "\t" + common; //$NON-NLS-1$
 					else
 						fReferenceIndentation= common;
 				}
 			}
 		}
 		super.append(range);
 	}

 	/*
 	 * @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#getContentLinePrefix()
 	 */
 	protected String getContentPrefix() {
 		return MULTI_COMMENT_CONTENT_PREFIX;
 	}

 	/*
 	 * @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#getEndLinePrefix()
 	 */
 	protected String getEndingPrefix() {
 		return MULTI_COMMENT_END_PREFIX;
 	}

 	/**
 	 * Returns the reference indentation to use for this line.
 	 *
 	 * @return the reference indentation for this line
 	 */
 	protected final String getIndentationReference() {
 		return fReferenceIndentation;
 	}

 	/*
 	 * @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#getStartLinePrefix()
 	 */
 	protected String getStartingPrefix() {
 		return MULTI_COMMENT_START_PREFIX;
 	}

 	/*
 	 * @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#scanLine(int)
 	 */
 	protected void scanLine(final int line) {

 		final CommentRegion parent= getParent();
 		final String start= getStartingPrefix().trim();
 		final String end= getEndingPrefix().trim();
 		final String content= getContentPrefix().trim();

 		final int lines= parent.getSize();
 		final CommentRange range= getFirst();

 		int offset= 0;
 		int postfix= 0;

 		String text= parent.getText(range.getOffset(), range.getLength());
 		if (line == 0) {

 			offset= text.indexOf(start);
 			if (offset >= 0 && text.substring(0, offset).trim().length() != 0)
 				offset= -1;

 			if (offset >= 0) {

 				offset += start.length();
 				range.trimBegin(offset);

 				postfix= text.lastIndexOf(end);
 				if (postfix >= 0 && text.substring(postfix + end.length()).trim().length() != 0)
 					postfix= -1;

 				if (postfix >= offset)
 					// comment ends on same line
 					range.setLength(postfix - offset);
 				else {
 					postfix= text.lastIndexOf(content);
 					if (postfix >= 0 && text.substring(postfix + content.length()).trim().length() != 0)
 						postfix= -1;

 					if (postfix >= offset) {

 						range.setLength(postfix - offset);
 						parent.setBorder(BORDER_UPPER);

 						if (postfix > offset) {

 							text= parent.getText(range.getOffset(), range.getLength());
 							final IRegion region= trimLine(text, content);

 							range.move(region.getOffset());
 							range.setLength(region.getLength());
 						}
 					}
 				}
 			}
 		} else if (line == lines - 1) {

 			offset= text.indexOf(content);
 			if (offset >= 0 && text.substring(0, offset).trim().length() != 0)
 				offset= -1;
 			postfix= text.lastIndexOf(end);
 			if (postfix >= 0 && text.substring(postfix + end.length()).trim().length() != 0)
 				postfix= -1;

 			if (offset >= 0 && offset == postfix)
 				// no content on line, only the comment postfix
 				range.setLength(0);
 			else {
 				if (offset >= 0)
 					// omit the content prefix
 					range.trimBegin(offset + content.length());

 				if (postfix >= 0)
 					// omit the comment postfix
 					range.trimEnd(-end.length());

 				text= parent.getText(range.getOffset(), range.getLength());
 				final IRegion region= trimLine(text, content);
 				if (region.getOffset() != 0 || region.getLength() != text.length()) {

 					range.move(region.getOffset());
 					range.setLength(region.getLength());

 					parent.setBorder(BORDER_UPPER);
 					parent.setBorder(BORDER_LOWER);
 				}
 			}
 		} else {

 			offset= text.indexOf(content);
 			if (offset >= 0 && text.substring(0, offset).trim().length() != 0)
 				offset= -1;

 			if (offset >= 0) {

 				offset += content.length();
 				range.trimBegin(offset);
 			}
 		}
 	}

 	/*
 	 * @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#tokenizeLine(int)
 	 */
 	protected void tokenizeLine(int line) {

 		int offset= 0;
 		int index= offset;

 		final CommentRegion parent= getParent();
 		final CommentRange range= getFirst();
 		final int begin= range.getOffset();

 		final String content= parent.getText(begin, range.getLength());
 		final int length= content.length();

 		while (offset < length && Character.isWhitespace(content.charAt(offset)))
 			offset++;

 		CommentRange result= null;
 		if (offset >= length && !parent.isClearLines() && (line > 0 && line < parent.getSize() - 1)) {

 			result= new CommentRange(begin, 0);
 			result.setAttribute(COMMENT_BLANKLINE);
 			result.setAttribute(COMMENT_FIRST_TOKEN);

 			parent.append(result);
 		}

 		int attribute= COMMENT_FIRST_TOKEN | COMMENT_STARTS_WITH_RANGE_DELIMITER;
 		while (offset < length) {

 			while (offset < length && Character.isWhitespace(content.charAt(offset))) {
 				offset++;
 				attribute |= COMMENT_STARTS_WITH_RANGE_DELIMITER;
 			}

 			index= offset;

 			if (index < length) {

 				if (content.charAt(index) == HTML_TAG_PREFIX) {

 					// in order to avoid recognizing any < in a comment, even those which are part of e.g.
 					// java source code, we validate the tag content to be one of the recognized
 					// tags (structural, breaks, pre, code).
 					int tag= ++index;
 					while (index < length && content.charAt(index) != HTML_TAG_POSTFIX && content.charAt(index) != HTML_TAG_PREFIX)
 						index++;

 					if (index < length && content.charAt(index) == HTML_TAG_POSTFIX && isValidTag(content.substring(tag, index))) {
 						index++;
 						attribute |= COMMENT_HTML; // only set html attribute if postfix found
 					} else {
 						// no tag - do the usual thing from the original offset
 						index= tag;
 						while (index < length && !Character.isWhitespace(content.charAt(index)) && content.charAt(index) != HTML_TAG_PREFIX && !content.startsWith(LINK_TAG_PREFIX, index))
 							index++;
 					}


 				} else if (content.startsWith(LINK_TAG_PREFIX, index)) {

 					while (index < length && content.charAt(index) != LINK_TAG_POSTFIX)
 						index++;

 					if (index < length && content.charAt(index) == LINK_TAG_POSTFIX)
 						index++;

 					attribute |= COMMENT_OPEN | COMMENT_CLOSE;

 				} else {

 					while (index < length && !Character.isWhitespace(content.charAt(index)) && content.charAt(index) != HTML_TAG_PREFIX && !content.startsWith(LINK_TAG_PREFIX, index))
 						index++;
 				}
 			}

 			if (index - offset > 0) {

 				result= new CommentRange(begin + offset, index - offset);
 				result.setAttribute(attribute);

 				parent.append(result);
 				offset= index;
 			}

 			attribute= 0;
 		}
 	}

 	/**
 	 * Checks whether <code>tag</code> is a valid tag content (text inside
 	 * the angular brackets &lt;, &gt;).
 	 * <p>
 	 * The algorithm is to see if the tag trimmed of whitespace and an
 	 * optional slash starts with one of our recognized tags.
 	 *
 	 * @param tag the tag to check
 	 * @return <code>true</code> if <code>tag</code> is a valid tag
 	 *         content
 	 */
 	private boolean isValidTag(String tag) {
 		// strip the slash
 		if (tag.startsWith("/")) //$NON-NLS-1$
 			tag= tag.substring(1, tag.length());

 		// strip ws
 		tag= tag.trim();

 		// extract first token
 		int i= 0;
 		while (i < tag.length() && !Character.isWhitespace(tag.charAt(i)))
 			i++;
 		tag= tag.substring(0, i);

 		// see if it's a tag
 		return isTagName(tag.toLowerCase());
 	}

 	/**
 	 * Checks whether <code>tag</code> is one of the configured tags.
 	 *
 	 * @param tag the tag to check
 	 * @return <code>true</code> if <code>tag</code> is a configured tag
 	 *         name
 	 */
 	private boolean isTagName(String tag) {
 		return fgTagLookup.contains(tag);
 	}

 	/**
 	 * Removes all leading and trailing occurrences from <code>line</code>.
 	 *
 	 * @param line the string to remove the occurrences of
 	 *                <code>trimmable</code>
 	 * @param trimmable the string to remove from <code>line</code>
 	 * @return the region of the trimmed substring within <code>line</code>
 	 */
 	protected final IRegion trimLine(final String line, final String trimmable) {

 		final int trim= trimmable.length();

 		int offset= 0;
 		int length= line.length() - trim;

 		while (line.startsWith(trimmable, offset))
 			offset += trim;

 		while (line.startsWith(trimmable, length))
 			length -= trim;

 		return new Region(offset, length + trim);
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2004 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
	*******************************************************************************/

	package org.eclipse.jdt.internal.formatter.comment;

	import java.util.HashSet;
	import java.util.Set;

	import org.eclipse.jface.text.IRegion;
	import org.eclipse.jface.text.Region;

	/**
	* Multi-line comment line in a comment region.
	*
	* @since 3.0
	*/
	public class MultiCommentLine extends CommentLine implements ICommentAttributes, IHtmlTagDelimiters, IJavaDocTagConstants {

	/** Line prefix of multi-line comment content lines */
	public static final String MULTI_COMMENT_CONTENT_PREFIX= " * "; //$NON-NLS-1$

	/** Line prefix of multi-line comment end lines */
	public static final String MULTI_COMMENT_END_PREFIX= " */"; //$NON-NLS-1$

	/** Line prefix of multi-line comment content lines */
	public static final String MULTI_COMMENT_START_PREFIX= "/* "; //$NON-NLS-1$

	/** The indentation reference of this line */
	private String fReferenceIndentation= ""; //$NON-NLS-1$

	/** The javadoc tag lookup. */
	private static final Set fgTagLookup;

	static {
	fgTagLookup= new HashSet();
	for (int i= 0; i < JAVADOC_BREAK_TAGS.length; i++) {
	fgTagLookup.add(JAVADOC_BREAK_TAGS[i]);
	}
	for (int i= 0; i < JAVADOC_SINGLE_BREAK_TAG.length; i++) {
	fgTagLookup.add(JAVADOC_SINGLE_BREAK_TAG[i]);
	}
	for (int i= 0; i < JAVADOC_CODE_TAGS.length; i++) {
	fgTagLookup.add(JAVADOC_CODE_TAGS[i]);
	}
	for (int i= 0; i < JAVADOC_IMMUTABLE_TAGS.length; i++) {
	fgTagLookup.add(JAVADOC_IMMUTABLE_TAGS[i]);
	}
	for (int i= 0; i < JAVADOC_NEWLINE_TAGS.length; i++) {
	fgTagLookup.add(JAVADOC_NEWLINE_TAGS[i]);
	}
	for (int i= 0; i < JAVADOC_SEPARATOR_TAGS.length; i++) {
	fgTagLookup.add(JAVADOC_SEPARATOR_TAGS[i]);
	}
	}

	/**
	* Creates a new multi-line comment line.
	*
	* @param region comment region to create the line for
	*/
	protected MultiCommentLine(final CommentRegion region) {
	super(region);
	}

	/*
	* @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#adapt(org.eclipse.jdt.internal.corext.text.comment.CommentLine)
	*/
	protected void adapt(final CommentLine previous) {

	if (!hasAttribute(COMMENT_ROOT) && !hasAttribute(COMMENT_PARAMETER) && !previous.hasAttribute(COMMENT_BLANKLINE))
	fReferenceIndentation= previous.getIndentationReference();
	}

	/*
	* @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#append(org.eclipse.jdt.internal.corext.text.comment.CommentRange)
	*/
	protected void append(final CommentRange range) {

	final MultiCommentRegion parent= (MultiCommentRegion)getParent();

	if (range.hasAttribute(COMMENT_PARAMETER))
	setAttribute(COMMENT_PARAMETER);
	else if (range.hasAttribute(COMMENT_ROOT))
	setAttribute(COMMENT_ROOT);
	else if (range.hasAttribute(COMMENT_BLANKLINE))
	setAttribute(COMMENT_BLANKLINE);

	final int ranges= getSize();
	if (ranges == 1) {

	if (parent.isIndentRoots()) {

	final CommentRange first= getFirst();
	final String common= parent.getText(first.getOffset(), first.getLength()) + CommentRegion.COMMENT_RANGE_DELIMITER;

	if (hasAttribute(COMMENT_ROOT))
	fReferenceIndentation= common;
	else if (hasAttribute(COMMENT_PARAMETER)) {
	if (parent.isIndentDescriptions())
	fReferenceIndentation= "\t" + common; //$NON-NLS-1$
	else
	fReferenceIndentation= common;
	}
	}
	}
	super.append(range);
	}

	/*
	* @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#getContentLinePrefix()
	*/
	protected String getContentPrefix() {
	return MULTI_COMMENT_CONTENT_PREFIX;
	}

	/*
	* @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#getEndLinePrefix()
	*/
	protected String getEndingPrefix() {
	return MULTI_COMMENT_END_PREFIX;
	}

	/**
	* Returns the reference indentation to use for this line.
	*
	* @return the reference indentation for this line
	*/
	protected final String getIndentationReference() {
	return fReferenceIndentation;
	}

	/*
	* @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#getStartLinePrefix()
	*/
	protected String getStartingPrefix() {
	return MULTI_COMMENT_START_PREFIX;
	}

	/*
	* @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#scanLine(int)
	*/
	protected void scanLine(final int line) {

	final CommentRegion parent= getParent();
	final String start= getStartingPrefix().trim();
	final String end= getEndingPrefix().trim();
	final String content= getContentPrefix().trim();

	final int lines= parent.getSize();
	final CommentRange range= getFirst();

	int offset= 0;
	int postfix= 0;

	String text= parent.getText(range.getOffset(), range.getLength());
	if (line == 0) {

	offset= text.indexOf(start);
	if (offset >= 0 && text.substring(0, offset).trim().length() != 0)
	offset= -1;

	if (offset >= 0) {

	offset += start.length();
	range.trimBegin(offset);

	postfix= text.lastIndexOf(end);
	if (postfix >= 0 && text.substring(postfix + end.length()).trim().length() != 0)
	postfix= -1;

	if (postfix >= offset)
	// comment ends on same line
	range.setLength(postfix - offset);
	else {
	postfix= text.lastIndexOf(content);
	if (postfix >= 0 && text.substring(postfix + content.length()).trim().length() != 0)
	postfix= -1;

	if (postfix >= offset) {

	range.setLength(postfix - offset);
	parent.setBorder(BORDER_UPPER);

	if (postfix > offset) {

	text= parent.getText(range.getOffset(), range.getLength());
	final IRegion region= trimLine(text, content);

	range.move(region.getOffset());
	range.setLength(region.getLength());
	}
	}
	}
	}
	} else if (line == lines - 1) {

	offset= text.indexOf(content);
	if (offset >= 0 && text.substring(0, offset).trim().length() != 0)
	offset= -1;
	postfix= text.lastIndexOf(end);
	if (postfix >= 0 && text.substring(postfix + end.length()).trim().length() != 0)
	postfix= -1;

	if (offset >= 0 && offset == postfix)
	// no content on line, only the comment postfix
	range.setLength(0);
	else {
	if (offset >= 0)
	// omit the content prefix
	range.trimBegin(offset + content.length());

	if (postfix >= 0)
	// omit the comment postfix
	range.trimEnd(-end.length());

	text= parent.getText(range.getOffset(), range.getLength());
	final IRegion region= trimLine(text, content);
	if (region.getOffset() != 0 \|\| region.getLength() != text.length()) {

	range.move(region.getOffset());
	range.setLength(region.getLength());

	parent.setBorder(BORDER_UPPER);
	parent.setBorder(BORDER_LOWER);
	}
	}
	} else {

	offset= text.indexOf(content);
	if (offset >= 0 && text.substring(0, offset).trim().length() != 0)
	offset= -1;

	if (offset >= 0) {

	offset += content.length();
	range.trimBegin(offset);
	}
	}
	}

	/*
	* @see org.eclipse.jdt.internal.corext.text.comment.CommentLine#tokenizeLine(int)
	*/
	protected void tokenizeLine(int line) {

	int offset= 0;
	int index= offset;

	final CommentRegion parent= getParent();
	final CommentRange range= getFirst();
	final int begin= range.getOffset();

	final String content= parent.getText(begin, range.getLength());
	final int length= content.length();

	while (offset < length && Character.isWhitespace(content.charAt(offset)))
	offset++;

	CommentRange result= null;
	if (offset >= length && !parent.isClearLines() && (line > 0 && line < parent.getSize() - 1)) {

	result= new CommentRange(begin, 0);
	result.setAttribute(COMMENT_BLANKLINE);
	result.setAttribute(COMMENT_FIRST_TOKEN);

	parent.append(result);
	}

	int attribute= COMMENT_FIRST_TOKEN \| COMMENT_STARTS_WITH_RANGE_DELIMITER;
	while (offset < length) {

	while (offset < length && Character.isWhitespace(content.charAt(offset))) {
	offset++;
	attribute \|= COMMENT_STARTS_WITH_RANGE_DELIMITER;
	}

	index= offset;

	if (index < length) {

	if (content.charAt(index) == HTML_TAG_PREFIX) {

	// in order to avoid recognizing any < in a comment, even those which are part of e.g.
	// java source code, we validate the tag content to be one of the recognized
	// tags (structural, breaks, pre, code).
	int tag= ++index;
	while (index < length && content.charAt(index) != HTML_TAG_POSTFIX && content.charAt(index) != HTML_TAG_PREFIX)
	index++;

	if (index < length && content.charAt(index) == HTML_TAG_POSTFIX && isValidTag(content.substring(tag, index))) {
	index++;
	attribute \|= COMMENT_HTML; // only set html attribute if postfix found
	} else {
	// no tag - do the usual thing from the original offset
	index= tag;
	while (index < length && !Character.isWhitespace(content.charAt(index)) && content.charAt(index) != HTML_TAG_PREFIX && !content.startsWith(LINK_TAG_PREFIX, index))
	index++;
	}


	} else if (content.startsWith(LINK_TAG_PREFIX, index)) {

	while (index < length && content.charAt(index) != LINK_TAG_POSTFIX)
	index++;

	if (index < length && content.charAt(index) == LINK_TAG_POSTFIX)
	index++;

	attribute \|= COMMENT_OPEN \| COMMENT_CLOSE;

	} else {

	while (index < length && !Character.isWhitespace(content.charAt(index)) && content.charAt(index) != HTML_TAG_PREFIX && !content.startsWith(LINK_TAG_PREFIX, index))
	index++;
	}
	}

	if (index - offset > 0) {

	result= new CommentRange(begin + offset, index - offset);
	result.setAttribute(attribute);

	parent.append(result);
	offset= index;
	}

	attribute= 0;
	}
	}

	/**
	* Checks whether <code>tag</code> is a valid tag content (text inside
	* the angular brackets <, >).
	* <p>
	* The algorithm is to see if the tag trimmed of whitespace and an
	* optional slash starts with one of our recognized tags.
	*
	* @param tag the tag to check
	* @return <code>true</code> if <code>tag</code> is a valid tag
	* content
	*/
	private boolean isValidTag(String tag) {
	// strip the slash
	if (tag.startsWith("/")) //$NON-NLS-1$
	tag= tag.substring(1, tag.length());

	// strip ws
	tag= tag.trim();

	// extract first token
	int i= 0;
	while (i < tag.length() && !Character.isWhitespace(tag.charAt(i)))
	i++;
	tag= tag.substring(0, i);

	// see if it's a tag
	return isTagName(tag.toLowerCase());
	}

	/**
	* Checks whether <code>tag</code> is one of the configured tags.
	*
	* @param tag the tag to check
	* @return <code>true</code> if <code>tag</code> is a configured tag
	* name
	*/
	private boolean isTagName(String tag) {
	return fgTagLookup.contains(tag);
	}

	/**
	* Removes all leading and trailing occurrences from <code>line</code>.
	*
	* @param line the string to remove the occurrences of
	* <code>trimmable</code>
	* @param trimmable the string to remove from <code>line</code>
	* @return the region of the trimmed substring within <code>line</code>
	*/
	protected final IRegion trimLine(final String line, final String trimmable) {

	final int trim= trimmable.length();

	int offset= 0;
	int length= line.length() - trim;

	while (line.startsWith(trimmable, offset))
	offset += trim;

	while (line.startsWith(trimmable, length))
	length -= trim;

	return new Region(offset, length + trim);
	}
	}