net.darkmist.clf.IndexedLogFileHandler.java Source code

Introduction

Here is the source code for net.darkmist.clf.IndexedLogFileHandler.java

Source

/*
 *  Copyright (C) 2012 Ed Schaller <schallee@darkmist.net>
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package net.darkmist.clf;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.zip.GZIPInputStream;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class IndexedLogFileHandler extends RegexChainedFileHandler {
    private static final Class<IndexedLogFileHandler> CLASS = IndexedLogFileHandler.class;
    private static final Log logger = LogFactory.getLog(CLASS);
    private static final String REGEX = "(.*\\.LOG)(?:|\\.gz)";
    private static final Pattern PATTERN = Pattern.compile(REGEX);
    private static final String INDEX_EXT = ".users.gz";
    private static final long MAX_BUF_SIZE = 1024 * 1024; // 1 meg

    private Pattern usrPat;

    public IndexedLogFileHandler(Pattern usrPat, FileHandler nextHandler) {
        super(PATTERN, nextHandler);
        this.usrPat = usrPat;
    }

    /** Checks for index file and presence of the user in the index if it exists.
     * @param file The log file being examined
     * @param base The base name of the log file
     * @return true if the index file exists and the index file does NOT contain the user.
     */
    private boolean notInIndex(File file, String base) {
        File dir;
        File index;
        InputStream in = null;
        String previousThreadName;
        Thread thread;
        int bufSize;

        if ((dir = file.getParentFile()) == null) {
            logger.warn("Log file " + file + " doesn't have a parent directory?");
            return false;
        }
        index = new File(dir, base + INDEX_EXT);
        if (!index.exists()) {
            if (logger.isDebugEnabled())
                logger.debug("no index file " + index + " for log file " + file);
            return false;
        }
        thread = Thread.currentThread();
        previousThreadName = thread.getName();
        thread.setName("idx: " + index);
        if (logger.isDebugEnabled())
            logger.debug("index scan of " + index);
        bufSize = (int) Math.min(index.length(), MAX_BUF_SIZE);
        try {
            in = new GZIPInputStream(new BufferedInputStream(new FileInputStream(index), bufSize));
            if (LineMatcher.readerContains(usrPat, new BufferedReader(new InputStreamReader(in)))) {
                logger.debug("found usr in index");
                return false;
            }
            logger.debug("did not find usr in index");
            return true;
        } catch (IOException e) {
            logger.warn("IOException reading from index " + index, e);
        } finally {
            in = Util.close(in, logger, index.toString());
            thread.setName(previousThreadName);
        }
        return false;
    }

    protected void nextHandler(File file) {
        Matcher matcher;
        String base;
        String previousThreadName;
        Thread thread;

        // get the base name...
        matcher = getMatcher();
        base = matcher.group(1);

        // check the index for it
        if (notInIndex(file, base))
            return;

        // pass it on
        thread = Thread.currentThread();
        previousThreadName = thread.getName();
        thread.setName("log: " + file);
        logger.info("scanning");
        try {
            super.nextHandler(file);
        } finally {
            thread.setName(previousThreadName);
        }
    }
}