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
015package org.apache.tapestry.engine;
016
017import 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 */
025public 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}