import org.apache.log4j.spi.Filter;
import org.apache.log4j.spi.LoggingEvent;

/**
 This is a very simple filter based on filtering by MDC key and value.
 */
public class MDCFilter extends Filter
{
    /**
     Do we return ACCEPT when a match occurs. Default is
     <code>false</code>, so that later filters get run by default  */
    boolean acceptOnMatch = false;

    String regexToMatch;
    String mdcKey;

    /**
     Return the decision of this filter.
     */
    public int decide(LoggingEvent event)
    {
        String mdcValue = (String) event.getMDC(mdcKey);
        boolean matches = mdcValue.matches(regexToMatch);
        
        if ((matches && acceptOnMatch) || (!matches && !acceptOnMatch))
        {
            return Filter.ACCEPT;
        }
        else
        {
            return Filter.DENY;
        }
    }

    public String getRegexToMatch()
    {
        return regexToMatch;
    }

    public void setRegexToMatch(String regexToMatch)
    {
        this.regexToMatch = regexToMatch;
    }

    public String getMDCKey()
    {
        return mdcKey;
    }

    public void setMDCKey(String mdcKey)
    {
        this.mdcKey = mdcKey;
    }

    /**
     Get the value of the <code>AcceptOnMatch</code> option.
     */
    public boolean getAcceptOnMatch()
    {
        return acceptOnMatch;
    }

    /**
     Set the <code>AcceptOnMatch</code> option.
     */
    public void setAcceptOnMatch(boolean acceptOnMatch)
    {
        this.acceptOnMatch = acceptOnMatch;
    }
}