001/*
002 * Copyright (c) 1998-2010 The Regents of the University of California.
003 * All rights reserved.
004 *
005 * '$Author: welker $'
006 * '$Date: 2010-05-06 05:21:26 +0000 (Thu, 06 May 2010) $' 
007 * '$Revision: 24234 $'
008 * 
009 * Permission is hereby granted, without written agreement and without
010 * license or royalty fees, to use, copy, modify, and distribute this
011 * software and its documentation for any purpose, provided that the above
012 * copyright notice and the following two paragraphs appear in all copies
013 * of this software.
014 *
015 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
016 * FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
017 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
018 * THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
019 * SUCH DAMAGE.
020 *
021 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
022 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
023 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
024 * PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
025 * CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
026 * ENHANCEMENTS, OR MODIFICATIONS.
027 *
028 */
029
030package org.geon;
031
032import java.net.HttpURLConnection;
033import java.net.URL;
034
035import ptolemy.actor.TypedAtomicActor;
036import ptolemy.actor.TypedIOPort;
037import ptolemy.actor.parameters.PortParameter;
038import ptolemy.data.BooleanToken;
039import ptolemy.data.StringToken;
040import ptolemy.data.type.BaseType;
041import ptolemy.kernel.CompositeEntity;
042import ptolemy.kernel.util.IllegalActionException;
043import ptolemy.kernel.util.NameDuplicationException;
044
045//////////////////////////////////////////////////////////////////////////
046//// URLExists
047/**
048 * Assert whether a given URL exists
049 * 
050 * @UserLevelDocumentation Assert whether a given URL exists.
051 * @author Efrat Jaeger
052 * @version $Id: URLExists.java 24234 2010-05-06 05:21:26Z welker $
053 */
054
055public class URLExists extends TypedAtomicActor {
056
057        /**
058         * Construct an actor with the given container and name.
059         * 
060         * @param container
061         *            The container.
062         * @param name
063         *            The name of this actor.
064         * @exception IllegalActionException
065         *                If the actor cannot be contained by the proposed
066         *                container.
067         * @exception NameDuplicationException
068         *                If the container already has an actor with this name.
069         */
070        public URLExists(CompositeEntity container, String name)
071                        throws NameDuplicationException, IllegalActionException {
072                super(container, name);
073
074                output = new TypedIOPort(this, "output", false, true);
075
076                // Set parameters.
077                url = new PortParameter(this, "url");
078
079                // set type constraints.
080                url.setTypeEquals(BaseType.STRING);
081                output.setTypeEquals(BaseType.BOOLEAN);
082        }
083
084        // /////////////////////////////////////////////////////////////////
085        // // parameters ////
086
087        /**
088         * Boolean output specifying whether the element is contained in the array.
089         * 
090         * @UserLevelDocumentation Boolean output specifying whether the element is
091         *                         contained in the array.
092         */
093        public TypedIOPort output;
094
095        /**
096         * The verified URL.
097         * 
098         * @UserLevelDocumentation The search element.
099         */
100        public PortParameter url;
101
102        // /////////////////////////////////////////////////////////////////
103        // // public methods ////
104
105        /**
106         * Consume a URL and verifies its existence.
107         */
108        public void fire() throws IllegalActionException {
109                // NOTE: This has be outside the if because we need to ensure
110                // that if an index token is provided that it is consumed even
111                // if there is no input token.
112                url.update();
113                String urlString = ((StringToken) url.getToken()).stringValue();
114                try {
115                        HttpURLConnection.setFollowRedirects(false);
116                        // note : you may also need
117                        // HttpURLConnection.setInstanceFollowRedirects(false)
118                        HttpURLConnection con = (HttpURLConnection) new URL(urlString)
119                                        .openConnection();
120                        con.setRequestMethod("HEAD");
121                        if (con.getResponseCode() == HttpURLConnection.HTTP_OK) {
122                                output.broadcast(new BooleanToken(true));
123                        } else {
124                                output.broadcast(new BooleanToken(false));
125                        }
126                } catch (Exception e) {
127                        System.out.println("unable to create httpurlconnection to "
128                                        + urlString);
129                        System.out.println(e.getMessage());
130                        output.broadcast(new BooleanToken(false));
131                }
132        }
133}