001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
005// * with the License.  You may obtain a copy of the License at                                                              *
006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.svl.vars;
014
015import static org.apache.juneau.common.internal.ArgUtils.*;
016
017import java.util.regex.*;
018
019import org.apache.juneau.svl.*;
020
021/**
022 * A logical variable resolver that resolves to <js>"true</js> if a pattern matches.
023 *
024 * <p>
025 * The format for this var is one of the following:
026 * <ul>
027 *    <li><js>"$PM{stringArg, pattern}"</js>
028 *    <li>...
029 * </ul>
030 *
031 * <p>
032 * The pattern can be any string optionally containing <js>'*'</js> or <js>'?'</js> representing any or one character
033 * respectively.
034 *
035 * <h5 class='section'>Example:</h5>
036 * <p class='bjava'>
037 *    <jc>// Create a variable resolver that resolves system properties and $SW vars.</jc>
038 *    VarResolver <jv>varResolver</jv> = VarResolver.<jsm>create</jsm>().vars(PatternMatchVar.<jk>class</jk>, SystemPropertiesVar.<jk>class</jk>).build();
039 *
040 *    <jc>// Use it!</jc>
041 *    System.<jsf>out</jsf>.println(<jv>varResolver</jv>.resolve(<js>"Running on Windows?  $PM{$P{os.name},*win*}!"</js>));
042 * </p>
043 *
044 * <p>
045 * Since this is a {@link MultipartVar}, any variables contained in the result will be recursively resolved.
046 * <br>Likewise, if the arguments contain any variables, those will be resolved before they are passed to this var.
047 *
048 * <h5 class='section'>See Also:</h5><ul>
049 *    <li class='link'><a class="doclink" href="../../../../../index.html#jm.SimpleVariableLanguage">Simple Variable Language</a>
050 * </ul>
051 */
052public class PatternMatchVar extends MultipartVar {
053
054   /** The name of this variable. */
055   public static final String NAME = "PM";
056
057   /**
058    * Constructor.
059    */
060   public PatternMatchVar() {
061      super(NAME);
062   }
063
064   @Override /* MultipartVar */
065   public String resolve(VarResolverSession session, String[] args) {
066      assertArg(args.length >= 2, "Invalid number of arguments passed to $PM var.  Must have 2 or more arguments.");
067
068      String stringArg = args[0];
069      String pattern = args[1];
070      Pattern p = Pattern.compile(pattern.replace("*", ".*").replace("?", "."));
071      return String.valueOf(p.matcher(stringArg).matches());
072   }
073}