Back to index...

	/*
	* Copyright (c) 1998, 2013, 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.html.parser;

	import java.util.Vector;
	import java.util.Enumeration;
	import java.io.*;


	/**
	* A representation of a content model. A content model is
	* basically a restricted BNF expression. It is restricted in
	* the sense that it must be deterministic. This means that you
	* don't have to represent it as a finite state automaton.<p>
	* See Annex H on page 556 of the SGML handbook for more information.
	*
	* @author Arthur van Hoff
	*
	*/
	public final class ContentModel implements Serializable {
	/**
	* Type. Either '*', '?', '+', ',', '\|', '&'.
	*/
	public int type;

	/**
	* The content. Either an Element or a ContentModel.
	*/
	public Object content;

	/**
	* The next content model (in a ',', '\|' or '&' expression).
	*/
	public ContentModel next;

	public ContentModel() {
	}

	/**
	* Create a content model for an element.
	*/
	public ContentModel(Element content) {
	this(0, content, null);
	}

	/**
	* Create a content model of a particular type.
	*/
	public ContentModel(int type, ContentModel content) {
	this(type, content, null);
	}

	/**
	* Create a content model of a particular type.
	*/
	public ContentModel(int type, Object content, ContentModel next) {
	this.type = type;
	this.content = content;
	this.next = next;
	}

	/**
	* Return true if the content model could
	* match an empty input stream.
	*/
	public boolean empty() {
	switch (type) {
	case '*':
	case '?':
	return true;

	case '+':
	case '\|':
	for (ContentModel m = (ContentModel)content ; m != null ; m = m.next) {
	if (m.empty()) {
	return true;
	}
	}
	return false;

	case ',':
	case '&':
	for (ContentModel m = (ContentModel)content ; m != null ; m = m.next) {
	if (!m.empty()) {
	return false;
	}
	}
	return true;

	default:
	return false;
	}
	}

	/**
	* Update elemVec with the list of elements that are
	* part of the this contentModel.
	*/
	public void getElements(Vector<Element> elemVec) {
	switch (type) {
	case '*':
	case '?':
	case '+':
	((ContentModel)content).getElements(elemVec);
	break;
	case ',':
	case '\|':
	case '&':
	for (ContentModel m=(ContentModel)content; m != null; m=m.next){
	m.getElements(elemVec);
	}
	break;
	default:
	elemVec.addElement((Element)content);
	}
	}

	private boolean valSet[];
	private boolean val[];
	// A cache used by first(). This cache was found to speed parsing
	// by about 10% (based on measurements of the 4-12 code base after
	// buffering was fixed).

	/**
	* Return true if the token could potentially be the
	* first token in the input stream.
	*/
	public boolean first(Object token) {
	switch (type) {
	case '*':
	case '?':
	case '+':
	return ((ContentModel)content).first(token);

	case ',':
	for (ContentModel m = (ContentModel)content ; m != null ; m = m.next) {
	if (m.first(token)) {
	return true;
	}
	if (!m.empty()) {
	return false;
	}
	}
	return false;

	case '\|':
	case '&': {
	Element e = (Element) token;
	if (valSet == null \|\| valSet.length <= Element.getMaxIndex()) {
	valSet = new boolean[Element.getMaxIndex() + 1];
	val = new boolean[valSet.length];
	}
	if (valSet[e.index]) {
	return val[e.index];
	}
	for (ContentModel m = (ContentModel)content ; m != null ; m = m.next) {
	if (m.first(token)) {
	val[e.index] = true;
	break;
	}
	}
	valSet[e.index] = true;
	return val[e.index];
	}

	default:
	return (content == token);
	// PENDING: refer to comment in ContentModelState
	/*
	if (content == token) {
	return true;
	}
	Element e = (Element)content;
	if (e.omitStart() && e.content != null) {
	return e.content.first(token);
	}
	return false;
	*/
	}
	}

	/**
	* Return the element that must be next.
	*/
	public Element first() {
	switch (type) {
	case '&':
	case '\|':
	case '*':
	case '?':
	return null;

	case '+':
	case ',':
	return ((ContentModel)content).first();

	default:
	return (Element)content;
	}
	}

	/**
	* Convert to a string.
	*/
	public String toString() {
	switch (type) {
	case '*':
	return content + "*";
	case '?':
	return content + "?";
	case '+':
	return content + "+";

	case ',':
	case '\|':
	case '&':
	char data[] = {' ', (char)type, ' '};
	String str = "";
	for (ContentModel m = (ContentModel)content ; m != null ; m = m.next) {
	str = str + m;
	if (m.next != null) {
	str += new String(data);
	}
	}
	return "(" + str + ")";

	default:
	return content.toString();
	}
	}
	}

Back to index...