001    // Copyright 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry.engine;
016    
017    import org.apache.tapestry.web.WebRequest;
018    
019    /**
020     * Utilities needed by engine services and etc.
021     * 
022     * @author Howard M. Lewis Ship
023     * @since 4.0
024     */
025    public class EngineUtils
026    {
027    
028        /**
029         * Invoked by {@link #getURL(String, String, int, String, boolean)} to see if an absolute URL is
030         * needed (because a specific scheme, server or port was indicated that does not match the
031         * incoming request).
032         * 
033         * @param scheme
034         *            the desired URL scheme, or null
035         * @param server
036         *            the desired URL server name, or null
037         * @param port
038         *            the desired URL port, or 0
039         * @param request
040         *            the request to check against
041         * @return true if absolute URL is needed, false otherwise
042         */
043        public static boolean needAbsoluteURL(String scheme, String server, int port, WebRequest request)
044        {
045            if (scheme != null && !scheme.equals(request.getScheme()))
046                return true;
047        
048            if (server != null && !server.equals(request.getServerName()))
049                return true;
050        
051            if (port != 0 && port != request.getServerPort())
052                return true;
053        
054            return false;
055        }
056    
057    }