001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
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004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
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006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
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011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.rest.vars;
014
015import org.apache.juneau.*;
016import org.apache.juneau.rest.*;
017import org.apache.juneau.rest.annotation.*;
018import org.apache.juneau.svl.*;
019
020/**
021 * URL variable resolver.
022 *
023 * <p>
024 * The format for this var is <js>"$U{uri}"</js>.
025 *
026 * <p>
027 * The advantage of using this variable is that you can resolve URLs with special protocols such as
028 * <js>"servlet:/xxx"</js>.
029 *
030 * <p>
031 * See {@link UriResolver} for the kinds of URIs that can be resolved.
032 * <ul>
033 *    <li>{@link HtmlDoc#widgets() @HtmlDoc(widgets)}
034 * </ul>
035 *
036 * <p>
037 * Uses the URI resolver returned by {@link RestRequest#getUriResolver()}.
038 *
039 * <h5 class='section'>See Also:</h5>
040 * <ul>
041 *    <li class='link'>{@doc juneau-rest-server.SvlVariables}
042 * </ul>
043 */
044public class UrlVar extends SimpleVar {
045
046   private static final String SESSION_req = "req";
047
048   /** The name of this variable. */
049   public static final String NAME = "U";
050
051   /**
052    * Constructor.
053    */
054   public UrlVar() {
055      super(NAME);
056   }
057
058   @Override /* Parameter */
059   public String resolve(VarResolverSession session, String key) {
060      RestRequest req = session.getSessionObject(RestRequest.class, SESSION_req, true);
061      return req.getUriResolver().resolve(key);
062   }
063}