/*
 * (c) Copyright 2010-2011 AgileBirds
 *
 * This file is part of OpenFlexo.
 *
 * OpenFlexo is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * OpenFlexo 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 General Public License
 * along with OpenFlexo. If not, see <http://www.gnu.org/licenses/>.
 *
 */
package org.openflexo.fge.geomedit.construction;

import java.util.Vector;

import org.openflexo.inspector.DefaultInspectableObject;
import org.openflexo.xmlcode.XMLSerializable;

public abstract class GeometricConstruction<O extends Object> extends DefaultInspectableObject implements XMLSerializable {

	private O computedData;

	protected abstract O computeData();

	public final O getData() {
		// System.out.println("getData() for "+this.getClass().getSimpleName());

		ensureUpToDate();

		if (computedData == null) {
			computedData = computeData();
		}

		return computedData;
	}

	private void ensureUpToDate() {
		ensureUpToDate(new Vector<GeometricConstruction>());
	}

	private void ensureUpToDate(Vector<GeometricConstruction> updatedConstructions) {
		// Recursively called ensureUpToDate() on dependancies
		if (getDepends() != null) {
			for (GeometricConstruction<?> c : getDepends()) {
				if (!c._altered.contains(this)) {
					c._altered.add(this);
				}
				c.ensureUpToDate(updatedConstructions);
			}
		}

		if (modified || updatedConstructions.size() > 0) {
			// System.out.println("Recompute data for "+this.getClass().getSimpleName());
			computedData = computeData();
			updatedConstructions.add(this);
			modified = false;
		}
	}

	public final void refresh() {
		// System.out.println("Refresh for "+this.getClass().getSimpleName());
		if (getDepends() != null) {
			for (GeometricConstruction c : getDepends()) {
				c.refresh();
			}
		}
		computedData = computeData();
	}

	@Override
	public abstract String toString();

	public abstract GeometricConstruction[] getDepends();

	private boolean modified = true;

	protected void setModified() {
		modified = true;
		for (GeometricConstruction c : _altered) {
			c.computedData = null;
			c.setModified();
		}
	}

	private Vector<GeometricConstruction> _altered = new Vector<GeometricConstruction>();

	@Override
	public String getInspectorName() {
		// Never inspected alone
		return null;
	}

}