AbstractNetSyslog.java

package org.graylog2.syslog4j.impl.net;

import java.net.InetAddress;

import org.graylog2.syslog4j.SyslogRuntimeException;
import org.graylog2.syslog4j.impl.AbstractSyslog;
import org.graylog2.syslog4j.util.SyslogUtility;

/**
 * AbstractNetSyslog is an abstract extension of AbstractSyslog
 * that provides support for network-based syslog clients.
 * <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: AbstractNetSyslog.java,v 1.7 2009/01/24 22:00:18 cvs Exp $
 */
public abstract class AbstractNetSyslog extends AbstractSyslog {
    private static final long serialVersionUID = -3250858945515853967L;

    protected static final Object cachedHostAddressSyncObject = new Object();

    protected InetAddress cachedHostAddress = null;

    protected AbstractNetSyslogConfigIF netSyslogConfig = null;

    protected void initialize() throws SyslogRuntimeException {
        try {
            this.netSyslogConfig = (AbstractNetSyslogConfigIF) this.syslogConfig;

        } catch (ClassCastException cce) {
            throw new SyslogRuntimeException("config must implement interface AbstractNetSyslogConfigIF");
        }
    }

    /**
     * @return Returns an object of InetAddress of the local host, using caching if so directed.
     */
    public InetAddress getHostAddress() {
        InetAddress hostAddress = null;

        if (this.netSyslogConfig.isCacheHostAddress()) {
            if (this.cachedHostAddress == null) {
                synchronized (cachedHostAddressSyncObject) {
                    if (this.cachedHostAddress == null) {
                        this.cachedHostAddress = SyslogUtility.getInetAddress(this.syslogConfig.getHost());
                    }
                }
            }

            hostAddress = this.cachedHostAddress;

        } else {
            hostAddress = SyslogUtility.getInetAddress(this.syslogConfig.getHost());
        }

        return hostAddress;
    }
}