| package org.apache.commons.digester3; |
| |
| /* |
| * 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. |
| */ |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| /** |
| * <p> |
| * Simple regex pattern matching algorithm. |
| * </p> |
| * <p> |
| * This uses just two wildcards: |
| * <ul> |
| * <li><code>*</code> matches any sequence of none, one or more characters |
| * <li><code>?</code> matches any one character |
| * </ul> |
| * Escaping these wildcards is not supported . |
| * </p> |
| * |
| * @since 1.5 |
| */ |
| public class SimpleRegexMatcher |
| extends RegexMatcher |
| { |
| |
| // --------------------------------------------------------- Fields |
| |
| /** Default log (class wide) */ |
| private static final Log BASE_LOG = LogFactory.getLog( SimpleRegexMatcher.class ); |
| |
| /** Custom log (can be set per object) */ |
| private Log log = BASE_LOG; |
| |
| // --------------------------------------------------------- Properties |
| |
| /** |
| * Gets the <code>Log</code> implementation. |
| * |
| * @return the <code>Log</code> implementation. |
| */ |
| public Log getLog() |
| { |
| return log; |
| } |
| |
| /** |
| * Sets the current <code>Log</code> implementation used by this class. |
| * |
| * @param log the current <code>Log</code> implementation used by this class. |
| */ |
| public void setLog( Log log ) |
| { |
| this.log = log; |
| } |
| |
| // --------------------------------------------------------- Public Methods |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean match( String basePattern, String regexPattern ) |
| { |
| // check for nulls |
| if ( basePattern == null || regexPattern == null ) |
| { |
| return false; |
| } |
| return match( basePattern, regexPattern, 0, 0 ); |
| } |
| |
| // --------------------------------------------------------- Implementations Methods |
| |
| /** |
| * Implementation of regex matching algorithm. This calls itself recursively. |
| * |
| * @param basePattern the standard digester path representing the element |
| * @param regexPattern the regex pattern the path will be tested against |
| * @param baseAt FIXME |
| * @param regexAt FIXME |
| */ |
| private boolean match( String basePattern, String regexPattern, int baseAt, int regexAt ) |
| { |
| if ( log.isTraceEnabled() ) |
| { |
| log.trace( "Base: " + basePattern ); |
| log.trace( "Regex: " + regexPattern ); |
| log.trace( "Base@" + baseAt ); |
| log.trace( "Regex@" + regexAt ); |
| } |
| |
| // check bounds |
| if ( regexAt >= regexPattern.length() ) |
| { |
| // maybe we've got a match |
| if ( baseAt >= basePattern.length() ) |
| { |
| // ok! |
| return true; |
| } |
| // run out early |
| return false; |
| |
| } |
| if ( baseAt >= basePattern.length() ) |
| { |
| // run out early |
| return false; |
| } |
| |
| // ok both within bounds |
| char regexCurrent = regexPattern.charAt( regexAt ); |
| switch ( regexCurrent ) |
| { |
| case '*': |
| // this is the tricky case |
| // check for terminal |
| if ( ++regexAt >= regexPattern.length() ) |
| { |
| // this matches anything let - so return true |
| return true; |
| } |
| // go through every subsequent apperance of the next character |
| // and so if the rest of the regex matches |
| char nextRegex = regexPattern.charAt( regexAt ); |
| if ( log.isTraceEnabled() ) |
| { |
| log.trace( "Searching for next '" + nextRegex + "' char" ); |
| } |
| int nextMatch = basePattern.indexOf( nextRegex, baseAt ); |
| while ( nextMatch != -1 ) |
| { |
| if ( log.isTraceEnabled() ) |
| { |
| log.trace( "Trying '*' match@" + nextMatch ); |
| } |
| if ( match( basePattern, regexPattern, nextMatch, regexAt ) ) |
| { |
| return true; |
| } |
| nextMatch = basePattern.indexOf( nextRegex, nextMatch + 1 ); |
| } |
| log.trace( "No matches found." ); |
| return false; |
| |
| case '?': |
| // this matches anything |
| return match( basePattern, regexPattern, ++baseAt, ++regexAt ); |
| |
| default: |
| if ( log.isTraceEnabled() ) |
| { |
| log.trace( "Camparing " + regexCurrent + " to " + basePattern.charAt( baseAt ) ); |
| } |
| if ( regexCurrent == basePattern.charAt( baseAt ) ) |
| { |
| // still got more to go |
| return match( basePattern, regexPattern, ++baseAt, ++regexAt ); |
| } |
| return false; |
| } |
| } |
| |
| } |