| // *************************************************************************************************************************** |
| // * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file * |
| // * distributed with this work for additional information regarding copyright ownership. The ASF licenses this file * |
| // * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance * |
| // * with the License. You may obtain a copy of the License at * |
| // * * |
| // * http://www.apache.org/licenses/LICENSE-2.0 * |
| // * * |
| // * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an * |
| // * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the * |
| // * specific language governing permissions and limitations under the License. * |
| // *************************************************************************************************************************** |
| package org.apache.juneau.svl.vars; |
| |
| import static org.apache.juneau.assertions.Assertions.*; |
| import java.util.regex.*; |
| |
| import org.apache.juneau.svl.*; |
| |
| /** |
| * A transformational variable that returns matched regex groups by given index. |
| * |
| * <p> |
| * The format for this var: |
| * <ul> |
| * <li><js>"$PE{arg,pattern,groupIndex}"</js> |
| * </ul> |
| * |
| * <p> |
| * The pattern can be any string optionally containing <js>'*'</js> or <js>'?'</js> representing any or one character |
| * respectively. |
| * |
| * <h5 class='section'>Example:</h5> |
| * <p class='bcode w800'> |
| * <jc>// Create a variable resolver that resolves system properties and $SW vars.</jc> |
| * VarResolver r = VarResolver.<jsm>create</jsm>().vars(PatternExtractVar.<jk>class</jk>, SystemPropertiesVar.<jk>class</jk>).build(); |
| * |
| * <jc>// Use it!</jc> |
| * System.<jsf>out</jsf>.println(r.resolve(<js>"Update = $PE{$P{java.version},_([0-9]+),1}!"</js>)); |
| * </p> |
| * |
| * <p> |
| * Since this is a {@link MultipartVar}, any variables contained in the result will be recursively resolved. |
| * <br>Likewise, if the arguments contain any variables, those will be resolved before they are passed to this var. |
| * |
| * <ul class='seealso'> |
| * <li class='link'>{@doc SvlVariables} |
| * </ul> |
| */ |
| public class PatternExtractVar extends MultipartVar { |
| |
| /** The name of this variable. */ |
| public static final String NAME = "PE"; |
| |
| /** |
| * Constructor. |
| */ |
| public PatternExtractVar() { |
| super(NAME); |
| } |
| |
| @Override /* MultipartVar */ |
| public String resolve(VarResolverSession session, String[] args) { |
| assertArg(args.length == 3, "Invalid number of arguments passed to $PE var. Must have 3 arguments."); |
| |
| String stringArg = args[0]; |
| String pattern = args[1]; |
| String result = ""; |
| int groupId = Integer.parseInt(args[2]); |
| |
| Pattern p = Pattern.compile(pattern.replace("*", ".*").replace("?", ".")); |
| Matcher m = p.matcher(stringArg); |
| |
| if (m.find() && groupId <= m.groupCount() && groupId >= 0) { |
| result = m.group(groupId); |
| } |
| |
| return result; |
| } |
| } |