com.dtstack.jlogstash.ua.parser.CachingParser.java Source code

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Here is the source code for com.dtstack.jlogstash.ua.parser.CachingParser.java

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/**
 * 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.
 */
package com.dtstack.jlogstash.ua.parser;

import java.io.IOException;
import java.io.InputStream;
import java.util.Map;

import org.apache.commons.collections.map.LRUMap;

import com.dtstack.jlogstash.ua.parser.Client;
import com.dtstack.jlogstash.ua.parser.Device;
import com.dtstack.jlogstash.ua.parser.OS;
import com.dtstack.jlogstash.ua.parser.Parser;
import com.dtstack.jlogstash.ua.parser.UserAgent;

/**
 * When doing webanalytics (with for example PIG) the main pattern is to process
 * weblogs in clickstreams. A basic fact about common clickstreams is that in
 * general the same browser will do multiple requests in sequence. This has the
 * effect that the same useragent will appear in the logfiles and we will see
 * the need to parse the same useragent over and over again.
 *
 * This class introduces a very simple LRU cache to reduce the number of times
 * the parsing is actually done.
 *
 * @author Niels Basjes
 *
 */
public class CachingParser extends Parser {

    // TODO: Make configurable
    private static final int CACHE_SIZE = 1000;

    private Map<String, Client> cacheClient = null;
    private Map<String, UserAgent> cacheUserAgent = null;
    private Map<String, Device> cacheDevice = null;
    private Map<String, OS> cacheOS = null;

    // ------------------------------------------

    public CachingParser() throws IOException {
        super();
    }

    public CachingParser(InputStream regexYaml) {
        super(regexYaml);
    }

    // ------------------------------------------

    @SuppressWarnings("unchecked")
    @Override
    public Client parse(String agentString) {
        if (agentString == null) {
            return null;
        }
        if (cacheClient == null) {
            cacheClient = new LRUMap(CACHE_SIZE);
        }
        Client client = cacheClient.get(agentString);
        if (client != null) {
            return client;
        }
        client = super.parse(agentString);
        cacheClient.put(agentString, client);
        return client;
    }

    // ------------------------------------------

    @SuppressWarnings("unchecked")
    @Override
    public UserAgent parseUserAgent(String agentString) {
        if (agentString == null) {
            return null;
        }
        if (cacheUserAgent == null) {
            cacheUserAgent = new LRUMap(CACHE_SIZE);
        }
        UserAgent userAgent = cacheUserAgent.get(agentString);
        if (userAgent != null) {
            return userAgent;
        }
        userAgent = super.parseUserAgent(agentString);
        cacheUserAgent.put(agentString, userAgent);
        return userAgent;
    }

    // ------------------------------------------

    @SuppressWarnings("unchecked")
    @Override
    public Device parseDevice(String agentString) {
        if (agentString == null) {
            return null;
        }
        if (cacheDevice == null) {
            cacheDevice = new LRUMap(CACHE_SIZE);
        }
        Device device = cacheDevice.get(agentString);
        if (device != null) {
            return device;
        }
        device = super.parseDevice(agentString);
        cacheDevice.put(agentString, device);
        return device;
    }

    // ------------------------------------------

    @SuppressWarnings("unchecked")
    @Override
    public OS parseOS(String agentString) {
        if (agentString == null) {
            return null;
        }

        if (cacheOS == null) {
            cacheOS = new LRUMap(CACHE_SIZE);
        }
        OS os = cacheOS.get(agentString);
        if (os != null) {
            return os;
        }
        os = super.parseOS(agentString);
        cacheOS.put(agentString, os);
        return os;
    }

    // ------------------------------------------

}