Package org.apache.tools.ant.taskdefs.condition

Class IsReachable

java.lang.Object

org.apache.tools.ant.ProjectComponent

org.apache.tools.ant.taskdefs.condition.IsReachable

All Implemented Interfaces:

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.

Since:

Ant 1.7

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_TIMEOUT	The default timeout.
static final String	ERROR_BAD_TIMEOUT	Error when invalid timeout value is defined
static final String	ERROR_BAD_URL	Error message when an invalid url is used.
static final String	ERROR_BOTH_TARGETS	Error message when url and host are specified.
static final String	ERROR_NO_HOST_IN_URL	Error message when no hostname in url.
static final String	ERROR_NO_HOSTNAME	Error when no hostname is defined
static final String	ERROR_ON_NETWORK	Network error message is seen.
static final String	METHOD_NAME	Deprecated. Since 1.10.6
static final String	MSG_NO_REACHABLE_TEST	Error message when no reachably test avail.

Fields inherited from class org.apache.tools.ant.ProjectComponent

description, location, project

Constructor Summary

Constructors

Constructor	Description
IsReachable()

Method Summary

Modifier and Type	Method	Description
boolean	eval()	Evaluate the condition.
void	setHost(String host)	Set the host to ping.
void	setTimeout(int timeout)	Set the timeout for the reachability test in seconds.
void	setUrl(String url)	Set the URL from which to extract the hostname.

Methods inherited from class org.apache.tools.ant.ProjectComponent

clone, getDescription, getLocation, getProject, log, log, setDescription, setLocation, setProject

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

DEFAULT_TIMEOUT

public static final int DEFAULT_TIMEOUT

The default timeout.

See Also:

• Constant Field Values

ERROR_NO_HOSTNAME

public static final String ERROR_NO_HOSTNAME

Error when no hostname is defined

See Also:

• Constant Field Values

ERROR_BAD_TIMEOUT

public static final String ERROR_BAD_TIMEOUT

Error when invalid timeout value is defined

See Also:

• Constant Field Values

ERROR_ON_NETWORK

public static final String ERROR_ON_NETWORK

Network error message is seen.

See Also:

• Constant Field Values

ERROR_BOTH_TARGETS

public static final String ERROR_BOTH_TARGETS

Error message when url and host are specified.

See Also:

• Constant Field Values

MSG_NO_REACHABLE_TEST

public static final String MSG_NO_REACHABLE_TEST

Error message when no reachably test avail.

See Also:

• Constant Field Values

ERROR_BAD_URL

public static final String ERROR_BAD_URL

Error message when an invalid url is used.

See Also:

• Constant Field Values

ERROR_NO_HOST_IN_URL

public static final String ERROR_NO_HOST_IN_URL

Error message when no hostname in url.

See Also:

• Constant Field Values

METHOD_NAME

@Deprecated
public static final String METHOD_NAME

Deprecated.

Since 1.10.6

The method name to look for in InetAddress

See Also:

• Constant Field Values

Constructor Details

IsReachable

public IsReachable()

Method Details

setHost

public void setHost(String host)

Set the host to ping.

Parameters:

host - the host to ping.

setUrl

public void setUrl(String url)

Set the URL from which to extract the hostname.

Parameters:

url - a URL object.

setTimeout

public void setTimeout(int timeout)

Set the timeout for the reachability test in seconds.

Parameters:

timeout - the timeout in seconds.

eval

public boolean eval()
             throws BuildException

Evaluate the condition.

Specified by:

eval in interface Condition

Returns:

true if the condition is true.

Throws:

BuildException - if an error occurs