001/*
002 * #%L
003 * Netarchivesuite - harvester
004 * %%
005 * Copyright (C) 2005 - 2014 The Royal Danish Library, the Danish State and University Library,
006 *             the National Library of France and the Austrian National Library.
007 * %%
008 * This program is free software: you can redistribute it and/or modify
009 * it under the terms of the GNU Lesser General Public License as
010 * published by the Free Software Foundation, either version 2.1 of the
011 * License, or (at your option) any later version.
012 * 
013 * This program is distributed in the hope that it will be useful,
014 * but WITHOUT ANY WARRANTY; without even the implied warranty of
015 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
016 * GNU General Lesser Public License for more details.
017 * 
018 * You should have received a copy of the GNU General Lesser Public
019 * License along with this program.  If not, see
020 * <http://www.gnu.org/licenses/lgpl-2.1.html>.
021 * #L%
022 */
023
024package dk.netarkivet.viewerproxy;
025
026import java.net.URI;
027import java.util.Observable;
028
029import dk.netarkivet.common.exceptions.ArgumentNotValid;
030
031/**
032 * A wrapper class for URI resolver, which also notifies an URIObserver about all URIs visited and their response codes.
033 */
034public class NotifyingURIResolver extends Observable implements URIResolver, URIResolverHandler {
035    /** The URIResolver used by this NotifyingURIResolver. */
036    private URIResolver ur;
037
038    /**
039     * Initialise the wrapper. Accepts the class to wrap and the observer to notify.
040     *
041     * @param ur The Wrapped URI resolver
042     * @param uo The URI Observer to notify on each url.
043     * @throws ArgumentNotValid if either argument is null.
044     */
045    public NotifyingURIResolver(URIResolver ur, URIObserver uo) {
046        ArgumentNotValid.checkNotNull(uo, "URIObserver uo");
047        addObserver(uo);
048        setURIResolver(ur);
049    }
050
051    /**
052     * Sets the current URIResolver wrapped.
053     *
054     * @param anUR URI resolver to wrap.
055     * @throws ArgumentNotValid if argument is null.
056     */
057    public void setURIResolver(URIResolver anUR) {
058        ArgumentNotValid.checkNotNull(anUR, "URIResolver anUR");
059        this.ur = anUR;
060    }
061
062    /**
063     * Passes the uri to the current wrapped resolver and notifies the observer of the result.
064     *
065     * @param request A given request
066     * @param response A given response
067     * @return the response code from the wrapped class
068     * @see URIResolver#lookup(Request, Response)
069     */
070    public int lookup(Request request, Response response) {
071        int responseCode = ur.lookup(request, response);
072        setChanged();
073        URI uri = null;
074        if (request != null) {
075            uri = request.getURI();
076        }
077        notifyObservers(new URIObserver.URIResponseCodePair(uri, responseCode));
078        return responseCode;
079    }
080}