com.carrotgarden.log4j.aws.sns.EvaluatorThrottler.java Source code

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Here is the source code for com.carrotgarden.log4j.aws.sns.EvaluatorThrottler.java

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/**
 * Copyright (C) 2010-2013 Andrei Pozolotin <Andrei.Pozolotin@gmail.com>
 *
 * All rights reserved. Licensed under the OSI BSD License.
 *
 * http://www.opensource.org/licenses/bsd-license.php
 */
package com.carrotgarden.log4j.aws.sns;

import java.util.Properties;
import java.util.concurrent.TimeUnit;

import org.apache.log4j.spi.LoggingEvent;
import org.codehaus.jackson.annotate.JsonProperty;

import com.carrotgarden.log4j.aws.sns.Signature.Mask;
import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;

/**
 * log4j event evaluator that throttles similar events via after-write time
 * based cache eviction
 * 
 * original idea from
 * 
 * https://github.com/insula/log4j-sns
 */
public class EvaluatorThrottler implements Evaluator {

    public static final String PROP_PERIOD = "period";
    public static final String PROP_UNIT = "unit";
    public static final String PROP_MASK = "mask";

    public static final int DEFAULT_PERIOD = 10;
    public static final TimeUnit DEFAULT_UNIT = TimeUnit.MINUTES;
    public static final Signature DEFAULT_SIGNATURE = Signature.DEFAULT;

    /** cache after-write retention period value */
    @JsonProperty
    protected long period = DEFAULT_PERIOD;

    /** cache after-write retention period unit */
    @JsonProperty
    protected TimeUnit timeUnit = DEFAULT_UNIT;

    /** cache event signature */
    @JsonProperty
    protected Signature signature = DEFAULT_SIGNATURE;

    /** event cache map : [ event-signature, is-event-present ] */
    private Cache<String, Boolean> eventCache;

    protected void ensureCache() {

        eventCache = CacheBuilder.newBuilder().expireAfterWrite(period, timeUnit).build();

    }

    public EvaluatorThrottler() {
        ensureCache();
    }

    @Override
    public void setProperties(final String propsText) {

        if (propsText == null) {
            return;
        }

        final Properties props = Util.propsFrom(propsText);

        period = Util.longFrom(props, PROP_PERIOD, DEFAULT_PERIOD);

        timeUnit = Util.unitFrom(props, PROP_UNIT, DEFAULT_UNIT);

        signature = new Signature(Util.maskFrom(props, PROP_MASK, Mask.DEFAULT));

        ensureCache();

    }

    /**  */
    @Override
    public boolean isTriggeringEvent(final LoggingEvent event) {

        final String key = signature.make(event);

        final boolean isNew = (eventCache.getIfPresent(key) == null);

        // LogLog.error("isNew=" + isNew);

        if (isNew) {

            eventCache.put(key, true);

            return true;

        } else {

            return false;

        }

    }

    public long getPeriod() {
        return period;
    }

    public void setPeriod(final long period) {
        this.period = period;
    }

    public TimeUnit getTimeUnit() {
        return timeUnit;
    }

    public void setTimeUnit(final TimeUnit timeUnit) {
        this.timeUnit = timeUnit;
    }

    public Signature getSignature() {
        return signature;
    }

    public void setSignature(final Signature signature) {
        this.signature = signature;
    }

}