LogParserFactory.java

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// Portions Copyright [2016] [Payara Foundation and/or its affiliates]

package com.sun.enterprise.server.logging.parser;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.sun.enterprise.server.logging.LogFormatHelper;
import com.sun.enterprise.util.LocalStringManagerImpl;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.util.zip.GZIPInputStream;

public class LogParserFactory {

    final private static LocalStringManagerImpl LOCAL_STRINGS = 
            new LocalStringManagerImpl(LogParserFactory.class);

    static final String NEWLINE = System.getProperty("line.separator");
    
    private static enum LogFormat {
        UNIFORM_LOG_FORMAT,
        ODL_LOG_FORMAT,
        UNKNOWN_LOG_FORMAT
    };
    
    private static final String ODL_LINE_HEADER_REGEX = 
        "\\[(\\d){4}\\-(\\d){2}\\-(\\d){2}T(\\d){2}\\:(\\d){2}\\:(\\d){2}\\.(\\d){3}[\\+|\\-](\\d){4}\\].*";
    
    private static final boolean DEBUG = false;
    
    private static class SingletonHolder {
        private static final LogParserFactory SINGLETON = new LogParserFactory();
    }
    
    public static LogParserFactory getInstance() {
        return SingletonHolder.SINGLETON;
    }

    private Pattern odlDateFormatPattern = null;
    
    private LogParserFactory() {
        odlDateFormatPattern  = Pattern.compile(ODL_LINE_HEADER_REGEX);
    }
    
    public LogParser createLogParser(File logFile) throws LogParserException, IOException {
        BufferedReader reader=null;
        try {
            if (LogFormatHelper.isCompressedFile(logFile.getName())) {
                reader = new BufferedReader(new InputStreamReader(new GZIPInputStream(new FileInputStream(logFile))));
            } else {
                reader = new BufferedReader(new FileReader(logFile));
            }
            String line = reader.readLine();
            LogFormat format = detectLogFormat(line);
            if (DEBUG) {
                System.out.println("Log format=" + format.name() + " for line:" + line);
            }
            switch(format) {
            case UNIFORM_LOG_FORMAT:
                return new UniformLogParser(logFile.getName());
            case ODL_LOG_FORMAT:
                return new ODLLogParser(logFile.getName());
            default:
                return new RawLogParser(logFile.getName());
            }
        } finally {
            if (reader != null) {
                reader.close();
            }
        }        
    }
    
    Pattern getODLDateFormatPattern() {
        return odlDateFormatPattern;    
    }
    
    private LogFormat detectLogFormat(String line) {
        if (line != null) {
            Matcher m = odlDateFormatPattern.matcher(line);
            if (m.matches()) {
                if (DEBUG) {
                    System.out.println("Matched ODL pattern for line:" + line);
                }
                return LogFormat.ODL_LOG_FORMAT;
            } else if (LogFormatHelper.isUniformFormatLogHeader(line)) {
                return LogFormat.UNIFORM_LOG_FORMAT;
            }             
        } 
        return LogFormat.UNKNOWN_LOG_FORMAT;
    }                
    
}