FoldingNodesVisitor.java

/*****************************************************************************
 * This file is part of Rinzo
 * 
 * Author: Claudio Cancinos WWW: https://sourceforge.net/projects/editorxml Copyright (C): 2008, Claudio Cancinos
 * 
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General
 * Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any
 * later version.
 * 
 * This program 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 for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License along with this program; If not, see
 * <http://www.gnu.org/licenses/>
 ****************************************************************************/
package com.amalto.workbench.widgets.xmlviewer.model.visitor;

import java.util.HashMap;
import java.util.Set;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.Position;
import org.eclipse.jface.text.source.Annotation;
import org.eclipse.jface.text.source.projection.ProjectionAnnotation;

import com.amalto.workbench.widgets.xmlviewer.model.XMLNode;
import com.amalto.workbench.widgets.xmlviewer.utils.FileUtils;

/**
 * Generates the list of segments to fold/unfold in the editor's projection
 * 
 */
public class FoldingNodesVisitor implements HierarchicalVisitor {
	private HashMap<ProjectionAnnotation, Position> newAnnotations = new HashMap<ProjectionAnnotation, Position>();
	private final IDocument document;

	public FoldingNodesVisitor(IDocument document) {
		this.document = document;
	}

	public boolean visitStart(XMLNode node) {
		try {
			if(!node.isEmpty() && 
				(node.isTag() || node.isCdata()) && 
				!node.isEndTag() &&
				!this.isInSameLine(node, node.getCorrespondingNode())) {

				int end = node.getCorrespondingNode().getOffset() + node.getCorrespondingNode().getLength();
				int length = end - node.getOffset() + FileUtils.LINE_SEPARATOR.length();
				if ((node.getOffset() + length) > this.document.getLength()) {
					length = length - FileUtils.LINE_SEPARATOR.length();
				}
				Position position = new Position(node.getOffset(), length);
				this.newAnnotations.put(new ProjectionAnnotation(), position);
			}
		} catch (Exception e) {
			// DO NOTHING. Failing folding detection should not cause an error.
		}
		return true;
	}

	public boolean visitEnd(XMLNode node) {
		return true;
	}

	public boolean visitChild(XMLNode node) {
		try {
			if((node.isCommentTag() || node.isCdata()) && 
					!this.isInSameLine(node.getOffset(), node.getOffset() + node.getLength())) {
				int length = node.getLength() + FileUtils.LINE_SEPARATOR.length();
				Position position = new Position(node.getOffset(), length);
				this.newAnnotations.put(new ProjectionAnnotation(), position);
			}
		} catch (Exception e) {
			// DO NOTHING. Failing folding detection should not cause an error.
		}
		return true;
	}

	public HashMap<ProjectionAnnotation, Position> getAnnotationsMap() {
		return this.newAnnotations;
	}

	public Annotation[] getAnnotations() {
		Set<ProjectionAnnotation> keySet = this.newAnnotations.keySet();
		Annotation[] keys = new Annotation[keySet.size()];
		keySet.toArray(keys);
		return keys;
	}

	private boolean isInSameLine(XMLNode node, XMLNode correspondingNode) {
		if(node == null || correspondingNode == null) {
			return false;
		} else {
			return this.isInSameLine(node.getOffset(), correspondingNode.getOffset());
		}
	}

	private boolean isInSameLine(int start, int end) {
		try {
			return this.document.getLineOfOffset(start) == this.document.getLineOfOffset(end);
		} catch (BadLocationException e) {
			return false;
		}
	}
	
}