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.juneau.rest.vars;
018
019import org.apache.juneau.*;
020import org.apache.juneau.http.response.*;
021import org.apache.juneau.rest.*;
022import org.apache.juneau.svl.*;
023
024/**
025 * URL variable resolver.
026 *
027 * <p>
028 * The format for this var is <js>"$U{uri}"</js>.
029 *
030 * <p>
031 * The advantage of using this variable is that you can resolve URLs with special protocols such as
032 * <js>"servlet:/xxx"</js>.
033 *
034 * <p>
035 * See {@link UriResolver} for the kinds of URIs that can be resolved.
036 *
037 * <p>
038 * This variable resolver requires that a {@link RestRequest} bean be available in the session bean store.
039 *
040 * <p>
041 * Uses the URI resolver returned by {@link RestRequest#getUriResolver()}.
042 *
043 * <h5 class='section'>See Also:</h5><ul>
044 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/RestServerSvlVariables">SVL Variables</a>
045 * </ul>
046 */
047public class UrlVar extends SimpleVar {
048
049   /** The name of this variable. */
050   public static final String NAME = "U";
051
052   /**
053    * Constructor.
054    */
055   public UrlVar() {
056      super(NAME);
057   }
058
059   @Override /* Var */
060   public String resolve(VarResolverSession session, String key) {
061      return session.getBean(RestRequest.class).orElseThrow(InternalServerError::new).getUriResolver().resolve(key);
062   }
063
064   @Override /* Var */
065   public boolean canResolve(VarResolverSession session) {
066      return session.getBean(RestRequest.class).isPresent();
067   }
068}