001    // Copyright 2011 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // 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
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry5.internal.services;
016    
017    import org.apache.tapestry5.services.StackTraceElementAnalyzer;
018    
019    import java.util.regex.Pattern;
020    
021    /**
022     * Uses a regular expression to identify which CSS class to apply to a frame. The frame's {@code toString()} is used. Uses
023     * {@link java.util.regex.Matcher#find()} to search for a subsequence of the frame's description.
024     *
025     * @since 5.3
026     */
027    public class RegexpStackTraceElementAnalyzer implements StackTraceElementAnalyzer
028    {
029        private final Pattern pattern;
030    
031        private final String cssClass;
032    
033        public RegexpStackTraceElementAnalyzer(Pattern pattern, String cssClass)
034        {
035            this.pattern = pattern;
036            this.cssClass = cssClass;
037        }
038    
039        public String classForFrame(StackTraceElement frame)
040        {
041            if (pattern.matcher(frame.toString()).find())
042            {
043                return cssClass;
044            }
045    
046            return null;
047        }
048    }