org.eclipse.vex.docbook/src/org/eclipse/vex/docbook/DocBookOutlineProvider.java

/*******************************************************************************
 * Copyright (c) 2004, 2008 John Krasnay 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:
 *     John Krasnay - initial API and implementation
 *     Igor Jacy Lino Campista - Java 5 warnings fixed (bug 311325)
 *******************************************************************************/
package org.eclipse.vex.docbook;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;

import org.eclipse.jface.viewers.IBaseLabelProvider;
import org.eclipse.jface.viewers.ILabelProvider;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.vex.core.internal.dom.Document;
import org.eclipse.vex.core.internal.dom.Element;
import org.eclipse.vex.ui.internal.editor.VexEditor;
import org.eclipse.vex.ui.internal.outline.IOutlineProvider;

/**
 * Provides an outline of the sections of a DocBook document.
 */
public class DocBookOutlineProvider implements IOutlineProvider {

	public void init(final VexEditor editor) {
	}

	public ITreeContentProvider getContentProvider() {
		return contentProvider;
	}

	public IBaseLabelProvider getLabelProvider() {
		return labelProvider;
	}

	public Element getOutlineElement(final Element child) {
		Element element = child;
		while (element.getParentElement() != null && !isTitledElement(element)) {
			element = element.getParentElement();
		}

		return element;
	}

	private final ITreeContentProvider contentProvider = new ITreeContentProvider() {

		public void dispose() {
		}

		public void inputChanged(final Viewer viewer, final Object oldInput, final Object newInput) {
		}

		public Object[] getChildren(final Object parentElement) {
			return getOutlineChildren((Element) parentElement);
		}

		public Object getParent(final Object element) {
			final Element parent = ((Element) element).getParentElement();
			if (parent == null) {
				return element;
			} else {
				return getOutlineElement(parent);
			}
		}

		public boolean hasChildren(final Object element) {
			return getOutlineChildren((Element) element).length > 0;
		}

		public Object[] getElements(final Object inputElement) {
			final Document document = (Document) inputElement;
			return new Object[] { document.getRootElement() };
		}

	};

	/**
	 * Returns an array of the children of the given element that represent nodes in the outline. These are elements
	 * such as "section" that contain "title" elements that we can use as label content.
	 * 
	 * @param element
	 * @return
	 */
	private Element[] getOutlineChildren(final Element element) {
		final List<Element> children = new ArrayList<Element>();
		for (final Element child : element.getChildElements()) {
			if (titledElements.contains(child.getLocalName())) {
				children.add(child);
			}
		}
		return children.toArray(new Element[children.size()]);
	}

	private final ILabelProvider labelProvider = new LabelProvider() {
		@Override
		public String getText(final Object o) {
			final Element e = (Element) o;
			Element titleChild = findChild(e, "title");
			if (titleChild != null) {
				return titleChild.getText();
			} else {
				final Element infoChild = findChild(e, e.getLocalName() + "info");
				if (infoChild != null) {
					titleChild = findChild(infoChild, "title");
					if (titleChild != null) {
						return titleChild.getText();
					}
				}
			}
			return e.getLocalName();
		}
	};

	/**
	 * Returns a value from a map of tag names that contain title elements The tags all have a similar characteristic.
	 * Their content model includes a <title/> element as the first or second child.
	 * 
	 * For simplicity, we assume that the document is valid w.r.t. the DTD and thus the 'title' element is optional and
	 * is one of the first two elements inside the given element.
	 * 
	 * @param element
	 * @return
	 */
	private boolean isTitledElement(final Element e) {

		if (titledElements.contains(e.getLocalName()) || e.getParent() == null) {
			final List<Element> children = e.getChildElements();
			if (children.size() > 0 && children.get(0).getLocalName().equals("title") || children.size() > 1 && children.get(1).getLocalName().equals("title")) {
				return true;
			}
		}
		return false;
	}

	/**
	 * Finds the first child of the given element with the given name. Returns null if none found. We should move this
	 * to XPath when we gain that facility.
	 */
	private Element findChild(final Element parent, final String childName) {
		for (final Element child : parent.getChildElements()) {
			if (child.getLocalName().equals(childName)) {
				return child;
			}
		}
		return null;
	}

	private final static int MAPSIZE = 101; // prime greater than 65/.80

	private final static HashSet<String> titledElements = new HashSet<String>(MAPSIZE);

	static {
		// Comment on each line indicates tags content model if different than title
		// We are only interested in location of title tag within Content Model
		// so any extra following content is ignored.

		// In general, it is impossible to keep this sort of table accurate and 
		// up-to-date for more than the most basic of cases. It would be better 
		// to extract this information from the DTD for the document.

		// For the moment, it is observed that this imperfect method works for 
		// vast majority of DocBook documents.

		titledElements.add("abstract"); // title?
		titledElements.add("article");
		//	titledElements.add("articleinfo"); 
		titledElements.add("appendix");
		//	titledElements.add("authorblurb"); // title?
		//	titledElements.add("bibliodiv");
		//	titledElements.add("calloutlist");
		//	titledElements.add("caution"); // title?
		titledElements.add("chapter"); // docinfo?, title
		//	titledElements.add("colophon");
		//	titledElements.add("constraintdef"); 
		//	titledElements.add("dedication");

		//	titledElements.add("equation"); // blockinfo?, title
		//	titledElements.add("example"); // blockinfo?, title
		//	titledElements.add("figure"); // blockinfo?, title
		titledElements.add("glossary"); // glossaryinfo?, title
		//	titledElements.add("glossdiv"); 
		//	titledElements.add("glosslist"); // blockinfo?, title
		//	titledElements.add("important"); // title?
		//	titledElements.add("index"); // indexinfo, title
		//	titledElements.add("indexdiv");
		//	titledElements.add("itemizedlist"); // blockinfo?, title

		//	titledElements.add("legalnotice"); // blockinfo?, title
		//	titledElements.add("lot"); // beginpage?, title
		//	titledElements.add("msg"); // title?
		//	titledElements.add("msgexplan"); // title?
		//	titledElements.add("msgmain"); // title?
		//	titledElements.add("msgrel"); // title?
		//	titledElements.add("msgset");
		//	titledElements.add("msgsub"); // title?
		//	titledElements.add("note"); // title?
		//	titledElements.add("orderedlist"); // blockinfo?, title

		titledElements.add("part"); // beginpage?, partinfo?, title
		titledElements.add("partintro");
		//	titledElements.add("personblurb"); // title?
		titledElements.add("preface"); // beginpage?, prefaceinfo?, title
		//	titledElements.add("procedure"); // blockinfo?, title
		//	titledElements.add("productionset");
		//	titledElements.add("qandadiv"); // blockinfo?, title
		//	titledElements.add("qandaset"); // blockinfo?, title
		//	titledElements.add("reference"); // beginpage?, referenceinfo?, title
		//	titledElements.add("refsect1"); // refsect1info?, title

		//	titledElements.add("refsect2"); // refsect2info, title
		//	titledElements.add("refsect3"); // refsect3info, title
		//	titledElements.add("refsection"); // refsectioninfo?, title
		//	titledElements.add("refsynopsisdiv"); // refsynopsisdivinfo?, title
		titledElements.add("sect1"); // sect1info?, title
		titledElements.add("sect2"); // sect2info?, title
		titledElements.add("sect3"); // sect3info?, title
		titledElements.add("sect4"); // sect4info?, title
		titledElements.add("sect5"); // sect5info?, title
		titledElements.add("section"); // sectioninfo?, title

		//	titledElements.add("segmentedlist"); 
		//	titledElements.add("set");
		//	titledElements.add("setindex"); // setindexinfo?, title
		//	titledElements.add("sidebar"); // sidebarinfo?, title
		titledElements.add("simplesect");
		//	titledElements.add("step"); // table?
		//	titledElements.add("table"); // blockinfo?, title
		//	titledElements.add("task"); // blockinfo?, title
		//	titledElements.add("taskprerequisites");// blockinfo?, title
		//	titledElements.add("taskrelated"); // blockinfo?, title

		//	titledElements.add("tasksummary"); // blockinfo?, title
		//	titledElements.add("tip"); // title?
		titledElements.add("toc"); // beginpage?, title
		//	titledElements.add("variablelist"); // blockinfo?, title
		//	titledElements.add("warning"); // title?
	}

}