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.http.response.*;
020import org.apache.juneau.rest.*;
021import org.apache.juneau.rest.servlet.*;
022import org.apache.juneau.svl.*;
023
024/**
025 * Servlet init parameter variable resolver.
026 *
027 * <p>
028 * The format for this var is <js>"$I{key[,defaultValue]}"</js>.
029 *
030 * <p>
031 * This variable resolver requires that a {@link RestRequest} bean be available in the session bean store.
032 *
033 * <p>
034 * Values are pulled from the {@link RestServlet#getInitParameter(String)} method.
035 *
036 * <p>
037 * Since this is a {@link SimpleVar}, any variables contained in the result will be recursively resolved.
038 * Likewise, if the arguments contain any variables, those will be resolved before they are passed to this var.
039 *
040 * <h5 class='section'>See Also:</h5><ul>
041 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/RestServerSvlVariables">SVL Variables</a>
042 * </ul>
043 */
044public class ServletInitParamVar extends DefaultingVar {
045
046   /** The name of this variable. */
047   public static final String NAME = "I";
048
049   /**
050    * Constructor.
051    */
052   public ServletInitParamVar() {
053      super(NAME);
054   }
055
056   @Override /* Var */
057   public String resolve(VarResolverSession session, String key) {
058      return session.getBean(RestRequest.class).orElseThrow(InternalServerError::new).getContext().getServletInitParameter(key);
059   }
060
061   @Override /* Var */
062   public boolean canResolve(VarResolverSession session) {
063      return session.getBean(RestRequest.class).isPresent();
064   }
065}