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 java.util.regex.*;
020
021import org.apache.juneau.common.utils.*;
022import org.apache.juneau.svl.*;
023
024/**
025 * A logical variable resolver that resolves to <js>"true</js> if a pattern matches.
026 *
027 * <p>
028 * The format for this var is one of the following:
029 * <ul>
030 *    <li><js>"$PM{stringArg, pattern}"</js>
031 *    <li>...
032 * </ul>
033 *
034 * <p>
035 * The pattern can be any string optionally containing <js>'*'</js> or <js>'?'</js> representing any or one character
036 * respectively.
037 *
038 * <h5 class='section'>Example:</h5>
039 * <p class='bjava'>
040 *    <jc>// Create a variable resolver that resolves system properties and $SW vars.</jc>
041 *    VarResolver <jv>varResolver</jv> = VarResolver.<jsm>create</jsm>().vars(PatternMatchVar.<jk>class</jk>, SystemPropertiesVar.<jk>class</jk>).build();
042 *
043 *    <jc>// Use it!</jc>
044 *    System.<jsf>out</jsf>.println(<jv>varResolver</jv>.resolve(<js>"Running on Windows?  $PM{$P{os.name},*win*}!"</js>));
045 * </p>
046 *
047 * <p>
048 * Since this is a {@link MultipartVar}, any variables contained in the result will be recursively resolved.
049 * <br>Likewise, if the arguments contain any variables, those will be resolved before they are passed to this var.
050 *
051 * <h5 class='section'>See Also:</h5><ul>
052 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/SimpleVariableLanguageBasics">Simple Variable Language Basics</a>
053 * </ul>
054 */
055public class PatternMatchVar extends MultipartVar {
056
057   /** The name of this variable. */
058   public static final String NAME = "PM";
059
060   /**
061    * Constructor.
062    */
063   public PatternMatchVar() {
064      super(NAME);
065   }
066
067   @Override /* MultipartVar */
068   public String resolve(VarResolverSession session, String[] args) {
069      Utils.assertArg(args.length >= 2, "Invalid number of arguments passed to $PM var.  Must have 2 or more arguments.");
070
071      String stringArg = args[0];
072      String pattern = args[1];
073      Pattern p = Pattern.compile(pattern.replace("*", ".*").replace("?", "."));
074      return String.valueOf(p.matcher(stringArg).matches());
075   }
076}