Class IsReachable

  • All Implemented Interfaces:
    java.lang.Cloneable, Condition

    public class IsReachable
    extends ProjectComponent
    implements Condition

    Test for a host being reachable using ICMP "ping" packets & echo operations. Ping packets are very reliable for assessing reachability in a LAN or WAN, but they do not get through any well-configured firewall. Echo (port 7) may.

    This condition turns unknown host exceptions into false conditions. This is because on a laptop, DNS is one of the first services lost when the network goes; you are implicitly offline.

    If a URL is supplied instead of a host, the hostname is extracted and used in the test--all other parts of the URL are discarded.

    The test may not work through firewalls; that is, something may be reachable using a protocol such as HTTP, while the lower level ICMP packets get dropped on the floor. Similarly, a host may be detected as reachable with ICMP, but not reachable on other ports (i.e. port 80), because of firewalls.

    Ant 1.7
    • Field Detail


        public static final int DEFAULT_TIMEOUT
        The default timeout.
        See Also:
        Constant Field Values

        public static final java.lang.String ERROR_NO_HOSTNAME
        Error when no hostname is defined
        See Also:
        Constant Field Values

        public static final java.lang.String ERROR_BAD_TIMEOUT
        Error when invalid timeout value is defined
        See Also:
        Constant Field Values

        public static final java.lang.String ERROR_ON_NETWORK
        Network error message is seen.
        See Also:
        Constant Field Values

        public static final java.lang.String ERROR_BOTH_TARGETS
        Error message when url and host are specified.
        See Also:
        Constant Field Values

        public static final java.lang.String MSG_NO_REACHABLE_TEST
        Error message when no reachably test avail.
        See Also:
        Constant Field Values

        public static final java.lang.String ERROR_BAD_URL
        Error message when an invalid url is used.
        See Also:
        Constant Field Values

        public static final java.lang.String ERROR_NO_HOST_IN_URL
        Error message when no hostname in url.
        See Also:
        Constant Field Values

        public static final java.lang.String METHOD_NAME
        Since 1.10.6
        The method name to look for in InetAddress
        See Also:
        Constant Field Values
    • Constructor Detail

      • IsReachable

        public IsReachable()
    • Method Detail

      • setHost

        public void setHost​(java.lang.String host)
        Set the host to ping.
        host - the host to ping.
      • setUrl

        public void setUrl​(java.lang.String url)
        Set the URL from which to extract the hostname.
        url - a URL object.
      • setTimeout

        public void setTimeout​(int timeout)
        Set the timeout for the reachability test in seconds.
        timeout - the timeout in seconds.