001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.wicket.request.mapper.parameter;
018
019import java.util.Iterator;
020
021import org.apache.wicket.request.Url;
022import org.apache.wicket.util.lang.Args;
023import org.apache.wicket.util.string.Strings;
024
025
026/**
027 * <p>
028 * Encodes page parameters into Url path fragments instead of the query string like the default
029 * {@link PageParametersEncoder}. The parameters are encoded in the following format:
030 * {@code /param1Name/param1Value/param2Name/param2Value}.
031 * </p>
032 * <strong>Note</strong>: Because of the nature of the encoder it doesn't support POST request
033 * parameters.
034 * <p>
035 * This used to be the default way of encoding page parameters in 1.4.x applications. Newer 1.5.x+
036 * applications use the query string, by default. This class facilitates backwards compatibility and
037 * migrations of 1.4.x application to 1.5.x+ codebase.
038 * <p>
039 * Example usage:
040 * {@code mount(new MountedMapper("/myPage", MyPage.class, new UrlPathPageParametersEncoder())); }
041 * 
042 * @author Chris Colman
043 * @author James Gilbertson
044 * @author ivaynberg
045 */
046public class UrlPathPageParametersEncoder implements IPageParametersEncoder
047{
048        @Override
049        public Url encodePageParameters(PageParameters params)
050        {
051                Args.notNull(params, "params");
052                Args.isTrue(params.getIndexedCount() == 0,
053                        "This encoder does not support indexed page parameters. Specified parameters: %s",
054                        params);
055
056                Url url = new Url();
057
058                for (PageParameters.NamedPair pair : params.getAllNamed())
059                {
060                        url.getSegments().add(pair.getKey());
061                        url.getSegments().add(pair.getValue());
062                }
063
064                return url;
065        }
066
067        @Override
068        public PageParameters decodePageParameters(Url url)
069        {
070                PageParameters params = new PageParameters();
071
072                for (Iterator<String> segment = url.getSegments().iterator(); segment.hasNext();)
073                {
074                        String key = segment.next();
075                        if (Strings.isEmpty(key))
076                        {
077                                // keys cannot be empty
078                                continue;
079                        }
080                        // A trailing slash can be seen as an extra segment with a "" value so check
081                        // if there is a matching value for this parameter name and ignore it if not
082                        if (segment.hasNext())
083                        {
084                                String value = segment.next();
085
086                                params.add(key, value, INamedParameters.Type.PATH);
087                        }
088                }
089
090                return params.isEmpty() ? null : params;
091        }
092}