001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
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006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
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012// ***************************************************************************************************************************
013package org.apache.juneau.rest.vars;
014
015import org.apache.juneau.*;
016import org.apache.juneau.http.response.*;
017import org.apache.juneau.rest.*;
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 *
033 * <p>
034 * This variable resolver requires that a {@link RestRequest} bean be available in the session bean store.
035 *
036 * <p>
037 * Uses the URI resolver returned by {@link RestRequest#getUriResolver()}.
038 *
039 * <h5 class='section'>See Also:</h5><ul>
040 *    <li class='link'><a class="doclink" href="../../../../../index.html#jm.SvlVariables">SVL Variables</a>
041 * </ul>
042 */
043public class UrlVar extends SimpleVar {
044
045   /** The name of this variable. */
046   public static final String NAME = "U";
047
048   /**
049    * Constructor.
050    */
051   public UrlVar() {
052      super(NAME);
053   }
054
055   @Override /* Var */
056   public String resolve(VarResolverSession session, String key) {
057      return session.getBean(RestRequest.class).orElseThrow(InternalServerError::new).getUriResolver().resolve(key);
058   }
059
060   @Override /* Var */
061   public boolean canResolve(VarResolverSession session) {
062      return session.getBean(RestRequest.class).isPresent();
063   }
064}