Example usage for java.util.logging LogRecord LogRecord

Introduction

In this page you can find the example usage for java.util.logging LogRecord LogRecord.

Prototype

public LogRecord(Level level, String msg)

Source Link

Document

Construct a LogRecord with the given level and message values.

Usage

From source file:hudson.model.Computer.java

/**
 * This method tries to compute the name of the host that's reachable by all the other nodes.
 *
 * <p>//from w ww  .ja  v  a 2 s . c o m
 * Since it's possible that the agent is not reachable from the master (it may be behind a firewall,
 * connecting to master via JNLP), this method may return null.
 *
 * It's surprisingly tricky for a machine to know a name that other systems can get to,
 * especially between things like DNS search suffix, the hosts file, and YP.
 *
 * <p>
 * So the technique here is to compute possible interfaces and names on the agent,
 * then try to ping them from the master, and pick the one that worked.
 *
 * <p>
 * The computation may take some time, so it employs caching to make the successive lookups faster.
 *
 * @since 1.300
 * @return
 *      null if the host name cannot be computed (for example because this computer is offline,
 *      because the agent is behind the firewall, etc.)
 */
public String getHostName() throws IOException, InterruptedException {
    if (hostNameCached)
        // in the worst case we end up having multiple threads computing the host name simultaneously, but that's not harmful, just wasteful.
        return cachedHostName;

    VirtualChannel channel = getChannel();
    if (channel == null)
        return null; // can't compute right now

    for (String address : channel.call(new ListPossibleNames())) {
        try {
            InetAddress ia = InetAddress.getByName(address);
            if (!(ia instanceof Inet4Address)) {
                LOGGER.log(Level.FINE, "{0} is not an IPv4 address", address);
                continue;
            }
            if (!ComputerPinger.checkIsReachable(ia, 3)) {
                LOGGER.log(Level.FINE, "{0} didn't respond to ping", address);
                continue;
            }
            cachedHostName = ia.getCanonicalHostName();
            hostNameCached = true;
            return cachedHostName;
        } catch (IOException e) {
            // if a given name fails to parse on this host, we get this error
            LogRecord lr = new LogRecord(Level.FINE, "Failed to parse {0}");
            lr.setThrown(e);
            lr.setParameters(new Object[] { address });
            LOGGER.log(lr);
        }
    }

    // allow the administrator to manually specify the host name as a fallback. HUDSON-5373
    cachedHostName = channel.call(new GetFallbackName());
    hostNameCached = true;
    return cachedHostName;
}