nl.basjes.parse.useragent.UserAgentAnalyzer Maven / Gradle / Ivy

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A parsing and analyzing library to get information from a useragent string.
There is a newer version: 7.28.1
/*
 * Yet Another UserAgent Analyzer
 * Copyright (C) 2013-2018 Niels Basjes
 *
 * Licensed 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 nl.basjes.parse.useragent;

import org.apache.commons.collections4.map.LRUMap;

import java.io.Serializable;

public class UserAgentAnalyzer extends UserAgentAnalyzerDirect implements Serializable {
    private static final int DEFAULT_PARSE_CACHE_SIZE = 10000;

    private int cacheSize = DEFAULT_PARSE_CACHE_SIZE;
    private LRUMap parseCache = null;

    public UserAgentAnalyzer() {
        super();
    }

    protected UserAgentAnalyzer(boolean initialize) {
        super(initialize);
    }

    public UserAgentAnalyzer(String resourceString) {
        super(resourceString);
    }

    public void disableCaching() {
        setCacheSize(0);
    }

    /**
     * Sets the new size of the parsing cache.
     * Note that this will also wipe the existing cache.
     *
     * @param newCacheSize The size of the new LRU cache. As size of 0 will disable caching.
     */
    public void setCacheSize(int newCacheSize) {
        cacheSize = newCacheSize > 0 ? newCacheSize : 0;
        if (cacheSize >= 1) {
            parseCache = new LRUMap<>(cacheSize);
        } else {
            parseCache = null;
        }
    }

    public int getCacheSize() {
        return cacheSize;
    }

    @Override
    public synchronized UserAgent parse(UserAgent userAgent) {
        if (userAgent == null) {
            return null;
        }
        userAgent.reset();

        if (parseCache == null) {
            return super.parse(userAgent);
        }

        String userAgentString = userAgent.getUserAgentString();
        UserAgent cachedValue = parseCache.get(userAgentString);
        if (cachedValue != null) {
            userAgent.clone(cachedValue);
        } else {
            cachedValue = new UserAgent(super.parse(userAgent));
            parseCache.put(userAgentString, cachedValue);
        }
        // We have our answer.
        return userAgent;
    }

    @SuppressWarnings("unchecked")
    public static UserAgentAnalyzerBuilder newBuilder() {
        return new UserAgentAnalyzerBuilder<>(new UserAgentAnalyzer(false));
    }

    // This is purely to retain backwards compatibility
    @SuppressWarnings("unchecked")
    public static class Builder extends UserAgentAnalyzerBuilder{
        public Builder(UserAgentAnalyzer newUaa) {
            super(newUaa);
        }
    }

    @SuppressWarnings("unchecked")
    public static class UserAgentAnalyzerBuilder>
            extends UserAgentAnalyzerDirectBuilder {
        private final UAA uaa;

        public UserAgentAnalyzerBuilder(UAA newUaa) {
            super(newUaa);
            this.uaa = newUaa;
        }

        public B withCache(int newCacheSize) {
            failIfAlreadyBuilt();
            uaa.setCacheSize(newCacheSize);
            return (B)this;
        }

        public B withoutCache() {
            failIfAlreadyBuilt();
            uaa.setCacheSize(0);
            return (B)this;
        }

        @SuppressWarnings("EmptyMethod") // We must override the method because of the generic return value.
        @Override
        public UAA build() {
            return super.build();
        }
    }
}