SequentialSyslogMessageModifier.java

package org.graylog2.syslog4j.impl.message.modifier.sequential;

import org.graylog2.syslog4j.SyslogIF;
import org.graylog2.syslog4j.SyslogMessageModifierIF;

/**
 * SequentialSyslogMessageModifier is an implementation of SyslogMessageModifierIF
 * that adds an incremented number at the end.
 * <p/>
 * <p>Syslog4j is licensed under the Lesser GNU Public License v2.1.  A copy
 * of the LGPL license is available in the META-INF folder in all
 * distributions of Syslog4j and in the base directory of the "doc" ZIP.</p>
 *
 * @author <syslog4j@productivity.org>
 * @version $Id: SequentialSyslogMessageModifier.java,v 1.8 2010/11/28 04:43:31 cvs Exp $
 */
public class SequentialSyslogMessageModifier implements SyslogMessageModifierIF {
    private static final long serialVersionUID = 6107735010240030785L;

    protected SequentialSyslogMessageModifierConfig config = null;

    protected long currentSequence[] = new long[LEVEL_DEBUG + 1];

    public static final SequentialSyslogMessageModifier createDefault() {
        SequentialSyslogMessageModifier modifier = new SequentialSyslogMessageModifier(SequentialSyslogMessageModifierConfig.createDefault());

        return modifier;
    }

    public SequentialSyslogMessageModifier(SequentialSyslogMessageModifierConfig config) {
        this.config = config;

        for (int i = 0; i < (LEVEL_DEBUG + 1); i++) {
            this.currentSequence[i] = config.getFirstNumber();
        }
    }

    protected String pad(long number) {
        StringBuffer buffer = new StringBuffer(Long.toString(number));

        while (buffer.length() < this.config.getLastNumberDigits()) {
            buffer.insert(0, this.config.getPadChar());
        }

        return buffer.toString();
    }

    public void setNextSequence(int level, long nextSequence) {
        if (nextSequence >= this.config.getFirstNumber() && nextSequence < this.config.getLastNumber()) {
            synchronized (this) {
                this.currentSequence[level] = nextSequence;
            }
        }
    }

    protected String nextSequence(int level) {
        long sequence = -1;

        synchronized (this) {
            sequence = this.currentSequence[level];

            if (this.currentSequence[level] >= this.config.getLastNumber()) {
                this.currentSequence[level] = this.config.getFirstNumber();

            } else {
                this.currentSequence[level]++;
            }
        }

        String _sequence = null;

        if (this.config.isUsePadding()) {
            _sequence = pad(sequence);

        } else {
            _sequence = Long.toString(sequence);
        }

        return _sequence;
    }

    public SequentialSyslogMessageModifierConfig getConfig() {
        return this.config;
    }

    public String modify(SyslogIF syslog, int facility, int level, String message) {
        StringBuffer buffer = new StringBuffer(message);

        buffer.append(this.config.getPrefix());
        buffer.append(nextSequence(level));
        buffer.append(this.config.getSuffix());

        return buffer.toString();
    }

    public boolean verify(String message) {
        // NO-OP

        return true;
    }
}