/*
 This file is part of the software framework JStatCom, 
 a library for building applications for data based analysis.

 Copyright (C) 2000-2005  Markus Kraetzig

 This library 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 2.1 of the
 License, or (at your option) any later version.

 This library 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
 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public
 License along with this library; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 USA
 */

package com.jstatcom.model;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * A support class for JSCData objects that manages adding,
 * removing and notification of the different JSCDataListener.
 * 

 * This class is not thread-save but clients must handle synchronization.
 * 
 * @author Markus Kraetzig 
 */
public final class JSCDataEventSupport {
    private Map> typeMap = null;

    /**
     * JSCDataEventSupport constructor.
     */
    public JSCDataEventSupport() {
        super();
    }

    /**
     * Adds evtListener to the list of listeners for events of
     * type evtType.
     * 
     * @param evtListener
     *            the JSCDataListener that gets notified whenever
     *            an event of evtType occurs
     * @param evtType
     *            the event type
     * @throws IllegalArgumentException
     *             if (evtListener == null || evtType == null)
     */
    public void addListener(JSCDataListener evtListener,
            JSCDataEventTypes evtType) {

        if (evtListener == null || evtType == null)
            throw new IllegalArgumentException("Argument was null.");

        if (typeMap == null)
            typeMap = new HashMap>();

        List toPut = null;
        if (!typeMap.containsKey(evtType)) { // First listener for that type.
            toPut = new ArrayList();
            typeMap.put(evtType, toPut);
        } else
            toPut = typeMap.get(evtType);

        if (!toPut.contains(evtListener))
            toPut.add(evtListener);
    }

    /**
     * Dispatches evt by calling valueChanged of
     * all registered listeners to events of type evt.getType.
     * 
     * @param evt
     *            the event to be dispatched
     * @throws IllegalArgumentException
     *             if (evt == null)
     */
    public void dispatchEvent(JSCDataEvent evt) {

        if (evt == null)
            throw new IllegalArgumentException("Argument was null.");

        // No listeners at all.
        if (typeMap == null || typeMap.size() == 0)
            return;

        // No listeners for that type.
        if (!typeMap.containsKey(evt.getType()))
            return;

        List currentList = (ArrayList) typeMap.get(evt.getType());
        for (int i = 0; i < currentList.size(); i++)
            ((JSCDataListener) currentList.get(i)).valueChanged(evt);

    }

    /**
     * Gets a list with all registered listeners for evtType.
     * 
     * @param evtType
     *            the event type
     * @return a copy of the respective list or an initialized list instance
     *         with size == 0 if no listeners are registered for
     *         evtType
     */
    public List getListenersForType(JSCDataEventTypes evtType) {

        if (!typeMap.containsKey(evtType))
            return new ArrayList();

        List list = typeMap.get(evtType);

        return new ArrayList(list);
    }

    /**
     * Removes evtListener from all listener lists. Nothing
     * happens if evtListener is currently not a listener.
     * 
     * @param evtListener
     *            the JSCDataListener to be removed
     * @throws IllegalArgumentException
     *             if (evtListener == null)
     */
    public void removeListener(JSCDataListener evtListener) {

        if (evtListener == null)
            throw new IllegalArgumentException("Argument was null.");

        // No listeners at all.
        if (typeMap == null || typeMap.size() == 0)
            return;

        Collection lists = typeMap.values();
        for (Iterator it = lists.iterator(); it.hasNext();) {
            List currentList = (ArrayList) it.next();
            currentList.remove(evtListener);
        }
    }

    /**
     * Gets a string representation of this.
     * 
     * @return informative string representation
     */
    public String toString() {
        StringBuffer str = new StringBuffer(super.toString() + "\n");

        if (typeMap == null || typeMap.size() == 0)
            str.append("no listeners registered\n");
        else {
            Collection lists = typeMap.values();
            Collection keys = typeMap.keySet();
            for (Iterator it = lists.iterator(), kit = keys.iterator(); it
                    .hasNext();)
                str.append(kit.next() + " " + it.next() + "\n");
        }
        return str.toString();

    }
}