LogFormatHelper.java

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

package com.sun.enterprise.server.logging;

import java.util.regex.Pattern;

/**
 * Helper class that provides methods to detect the log format of a record. 
 *
 */
public class LogFormatHelper {

    private static final int ODL_SUBSTRING_LEN = 5;
    
    private static final String ODL_LINE_BEGIN_REGEX = "\\[(\\d){4}";
    
    private static final String GZIP_EXTENSION = ".gz";

    private static final class PatternHolder {
        private static final Pattern ODL_PATTERN = Pattern.compile(ODL_LINE_BEGIN_REGEX);
    }
    
    /**
     * Determines whether the given line is the beginning of a UniformLogFormat log record.
     * @param line
     * @return
     */
    public static boolean isUniformFormatLogHeader(String line) {
        if (line.startsWith("[#|") && countOccurrences(line, '|') > 4) { 
            return true;
        } else {
            return false;
        }
    }
    
    /**
     * Determines whether the given line is the beginning of a ODL log record.
     * @param line
     * @return
     */
    public static boolean isODLFormatLogHeader(String line) {
        if (line.length() > ODL_SUBSTRING_LEN
                && PatternHolder.ODL_PATTERN.matcher(
                        line.substring(0, ODL_SUBSTRING_LEN))
                        .matches()
                && countOccurrences(line, '[') > 4) {
            return true;
        } else {
            return false;
        }
    }

    private static int countOccurrences(String haystack, char needle) {
        int count = 0;
        for (int i = 0; i < haystack.length(); i++) {
            if (haystack.charAt(i) == needle) {
                count++;
            }
        }
        return count;
    }

    /**
     * Determines whether the given file is compressed (name ends with .gz).
     * @param filename
     * @return
     */
    public static boolean isCompressedFile(String filename) {
        return filename.endsWith(GZIP_EXTENSION);
    }
    
}