org.eclipse.viatra2.core2/src/org/eclipse/viatra2/framework/properties/VPMProperties.java

/*******************************************************************************
 * Copyright (c) 2004-2008 Andras Schmidt, Andras Balogh, Istvan Rath and Daniel Varro
 * 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:
 *    Andras Schmidt, Andras Balogh, Istvan Rath - initial API and implementation
 *******************************************************************************/

package org.eclipse.viatra2.framework.properties;

import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Properties;
import java.util.Set;
import java.util.Vector;

import org.eclipse.viatra2.framework.properties.providers.DummyPropertyProvider;

/**
 * Dynamic multiple properties for VPM modeling.
 * 
 * Note: this class has (too) many functionalities. Note2: all getter functions
 * implicitly assume that they are queried with registered provider IDs.
 * 
 * @author Istvan Rath
 * 
 */
public class VPMProperties {
	private static final long serialVersionUID = 3838142787694854860L;

	/**
	 * String -> PropertyProvider mapping.
	 */
	private HashMap<String, IViatraPropertyProvider> multiProperties;

	/**
	 * Container to keep track of listeners which receive a notification when a
	 * new provider is registered or deregistered.
	 */
	private Vector<IViatraPropertyProvidersChangedListener> listeners;

	public VPMProperties() {
		multiProperties = new HashMap<String, IViatraPropertyProvider>();
		listeners = new Vector<IViatraPropertyProvidersChangedListener>();
	}

	public boolean isProviderActive(String providerID) {
		return multiProperties.containsKey(providerID)
				&& multiProperties.get(providerID).isActive();
	}

	public void addPropertyProvider(IViatraPropertyProvider provider) {
		if (!multiProperties.containsKey(provider)) {
			multiProperties.put(provider.getProviderID(), provider);
			// FIXME what if there exists a dummy provider for this provider ID?
			notifyListeners();
		}
	}

	public void removePropertyProvider(IViatraPropertyProvider provider) {
		if (multiProperties.containsKey(provider)) {
			multiProperties.remove(provider.getProviderID());
			// FIXME what to do with dummy?
			notifyListeners();
		}
	}

	public Set<String> getAllProviderIDs() {
		return multiProperties.keySet();
	}

	/**
	 * Returns a property provider with a given ID.
	 * 
	 * @param providerID
	 *            provider ID string
	 * @return property provider object
	 */
	public IViatraPropertyProvider getProvider(String providerID) {
		return multiProperties.get(providerID);
	}

	/**
	 * Returns all the Property Keys of the Properties container of this
	 * IFramework.
	 */
	public Set<String> getAllRuntimePropertyIDs(String providerID) {
		return multiProperties.get(providerID).getAllPropertyIds();
	}

	/**
	 * Sets a runtime property of this IFramework instance
	 * 
	 * @param propid
	 *            the runtime property's unique string id
	 * @param value
	 *            the desired value
	 */
	public void setRuntimeProperty(String providerID, String propid,
			String value) {
		if (multiProperties.get(providerID) != null)
			multiProperties.get(providerID).setProperty(propid, value);
	}

	/**
	 * Gets the value of a runtime property of this IFramework instance
	 * 
	 * @param propid
	 *            the runtime property's unique string id
	 * @return the value of the runtime property, empty string if not found!
	 */
	public String getRuntimeProperty(String providerID, String propid) {
		if (multiProperties.get(providerID) != null)
			return multiProperties.get(providerID).getProperty(propid);
		else
			//return null;
			return "";
	}

	/**
	 * Gets whether a given runtime property is set for a given provider id.
	 * 
	 * @param providerID
	 * @param propid
	 * @return true if the property is set
	 */
	public boolean isRuntimePropertySet(String providerID, String propid) {
		try {
			return multiProperties.get(providerID).getProperty(propid) != null;
		} catch (Exception e) {
			return false;
		}
	}

	/**
	 * This method is used to load the multiproperties from a
	 * java.util.Properties serialization. Its use is discouraged as we should
	 * load properties from VPML files now.
	 * 
	 * @param s
	 * @throws IOException
	 */
	public void load(InputStream s) throws IOException {
		Properties p = new Properties();
		p.load(s);
		loadFromJavaProperties(p);
	}

	private static final String ProviderIDPrefixDelimiter = "@";

	/**
	 * Recreate the multi property registry from a simple java.util.Properties
	 * instance.
	 * 
	 * Note: this function must be called AFTER all active property providers
	 * have been registered.
	 * 
	 * @param p
	 */
	public void loadFromJavaProperties(Properties p) {
		for (Object _key : p.keySet().toArray()) {
			String key = _key.toString();
			if (key.indexOf(ProviderIDPrefixDelimiter) < 0) {
				// System.out.println("Invalid property key: "+key);
				continue;
			}
			String providerID = key.substring(0, key
					.indexOf(ProviderIDPrefixDelimiter));
			String propid = key.substring(key
					.indexOf(ProviderIDPrefixDelimiter)
					+ ProviderIDPrefixDelimiter.length());
			if (!multiProperties.containsKey(providerID)) {
				// no currently active provider
				// create dummy provider
				DummyPropertyProvider dp = new DummyPropertyProvider(providerID);
				addPropertyProvider(dp);
			}
			setRuntimeProperty(providerID, propid, p.get(key).toString());
		}
	}

	/**
	 * "Serialize" as a standard java.util.Properties instance. In this
	 * registry, property keys are prefixed by
	 * ProviderID+ProProviderIDPrefixDelimiter
	 */
	public Properties getJavaProperties() {
		Properties p = new Properties();
		for (String key : multiProperties.keySet()) {
			IViatraPropertyProvider prov = multiProperties.get(key);
			for (String _key : prov.getAllPropertyIds()) {
				p.put(prov.getProviderID() + ProviderIDPrefixDelimiter + _key,
						prov.getProperty(_key));
			}
		}
		return p;
	}

	/**
	 * Register a new listener for providerset changed events.
	 * 
	 * @param l
	 */
	public void addProvideryProvidersChangedListener(
			IViatraPropertyProvidersChangedListener l) {
		if (!listeners.contains(l))
			listeners.add(l);
	}

	/**
	 * Deregister a listener for providerset changed events.
	 * 
	 * @param l
	 */
	public void removeProvideryProvidersChangedListener(
			IViatraPropertyProvidersChangedListener l) {
		if (listeners.contains(l)) {
			listeners.remove(l);
			listeners.trimToSize();
		}
	}

	private void notifyListeners() {
		for (IViatraPropertyProvidersChangedListener l : listeners) {
			l.propertyProvidersChanged();
		}
	}

}