/*******************************************************************************
 * Copyright (c) 2000, 2005 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.pde.internal.core.plugin;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

import javax.xml.parsers.FactoryConfigurationError;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.osgi.service.resolver.BundleDescription;
import org.eclipse.pde.core.IModelChangedEvent;
import org.eclipse.pde.core.ModelChangedEvent;
import org.eclipse.pde.core.plugin.IExtensions;
import org.eclipse.pde.core.plugin.IExtensionsModel;
import org.eclipse.pde.core.plugin.IExtensionsModelFactory;
import org.eclipse.pde.core.plugin.IPluginAttribute;
import org.eclipse.pde.core.plugin.IPluginElement;
import org.eclipse.pde.core.plugin.IPluginExtension;
import org.eclipse.pde.core.plugin.IPluginExtensionPoint;
import org.eclipse.pde.core.plugin.IPluginObject;
import org.eclipse.pde.internal.core.AbstractModel;
import org.eclipse.pde.internal.core.PDEState;
import org.xml.sax.SAXException;

public abstract class AbstractExtensionsModel
	extends AbstractModel
	implements IExtensionsModel, IExtensionsModelFactory {
	protected Extensions fExtensions;

	public IExtensionsModelFactory getFactory() {
		return this;
	}
	
	protected Extensions createExtensions() {
		Extensions extensions = new Extensions();
		extensions.setModel(this);
		return extensions;
	}

	public IExtensions getExtensions() {
		return getExtensions(true);
	}
	public IExtensions getExtensions(boolean createIfMissing) {
		if (fExtensions == null && createIfMissing) {
			fExtensions = createExtensions();
			setLoaded(true);
		}
		return fExtensions;
	}

	public abstract URL getNLLookupLocation();

	protected URL[] getNLLookupLocations() {
		URL locations [] = { getNLLookupLocation() };
		return locations;
	}

	public synchronized void load(InputStream stream, boolean outOfSync)
		throws CoreException {

		if (fExtensions == null) {
			fExtensions = createExtensions();
			fExtensions.setModel(this);
		}
		fExtensions.reset();
		setLoaded(false);
		try {
			SAXParser parser = getSaxParser();
			PluginHandler handler = new PluginHandler(true);
			parser.parse(stream, handler);
			fExtensions.load(handler.getDocumentElement());
			setLoaded(true);
			if (!outOfSync)
				updateTimeStamp();
		} catch (ParserConfigurationException e) {
		} catch (SAXException e) {
		} catch (FactoryConfigurationError e) {
		} catch (IOException e) {
		}
	}
	
	public void load(BundleDescription desc, PDEState state) {
		fExtensions = createExtensions();
		fExtensions.setModel(this);
		fExtensions.load(state.getAllExtensions(desc.getBundleId()));
		updateTimeStamp();
		setLoaded(true);
	}

	public void reload(InputStream stream, boolean outOfSync)
		throws CoreException {
		load(stream, outOfSync);
		fireModelChanged(
			new ModelChangedEvent(this,
				IModelChangedEvent.WORLD_CHANGED,
				new Object[] { fExtensions },
				null));
	}
	protected abstract void updateTimeStamp();

	public IPluginAttribute createAttribute(IPluginElement element) {
		PluginAttribute attribute = new PluginAttribute();
		attribute.setModel(this);
		attribute.setParent(element);
		return attribute;
	}
	public IPluginElement createElement(IPluginObject parent) {
		PluginElement element = new PluginElement();
		element.setModel(this);
		element.setParent(parent);
		return element;
	}
	public IPluginExtension createExtension() {
		PluginExtension extension = new PluginExtension();
		extension.setParent(getExtensions());
		extension.setModel(this);
		return extension;
	}
	public IPluginExtensionPoint createExtensionPoint() {
		PluginExtensionPoint extensionPoint = new PluginExtensionPoint();
		extensionPoint.setModel(this);
		extensionPoint.setParent(getExtensions());
		return extensionPoint;
	}
	
	public boolean isValid() {
		if (!isLoaded()) return false;
		if (fExtensions==null) return false;
		return fExtensions.isValid();	
	}
}
