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.svl.vars;
018
019import org.apache.juneau.svl.*;
020
021/**
022 * A basic variable resolver that returns the first non-null value.
023 *
024 * <p>
025 * The format for this var is <js>"$CO{arg1[,arg2...]}"</js>.
026 *
027 * <h5 class='section'>See Also:</h5><ul>
028 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/SimpleVariableLanguageBasics">Simple Variable Language Basics</a>
029 * </ul>
030 */
031public class CoalesceVar extends MultipartResolvingVar {
032
033   /** The name of this variable. */
034   public static final String NAME = "CO";
035
036   /**
037    * Constructor.
038    */
039   public CoalesceVar() {
040      super(NAME);
041   }
042
043   @Override
044   public String resolve(VarResolverSession session, String arg) throws Exception {
045      return arg;
046   }
047}