Class IsReachable
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
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic intThe default timeout.static StringError when invalid timeout value is definedstatic StringError message when an invalid url is used.static StringError message when url and host are specified.static StringError message when no hostname in url.static StringError when no hostname is definedstatic StringNetwork error message is seen.static StringDeprecated.Since 1.10.6static StringError message when no reachably test avail.Fields inherited from class org.apache.tools.ant.ProjectComponent
description, location, project -
Constructor Summary
Constructors -
Method Summary
Methods inherited from class org.apache.tools.ant.ProjectComponent
clone, getDescription, getLocation, getProject, log, log, setDescription, setLocation, setProject
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Field Details
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DEFAULT_TIMEOUT
public static final int DEFAULT_TIMEOUTThe default timeout.- See Also:
- Constant Field Values
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ERROR_NO_HOSTNAME
Error when no hostname is defined- See Also:
- Constant Field Values
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ERROR_BAD_TIMEOUT
Error when invalid timeout value is defined- See Also:
- Constant Field Values
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ERROR_ON_NETWORK
Network error message is seen.- See Also:
- Constant Field Values
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ERROR_BOTH_TARGETS
Error message when url and host are specified.- See Also:
- Constant Field Values
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MSG_NO_REACHABLE_TEST
Error message when no reachably test avail.- See Also:
- Constant Field Values
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ERROR_BAD_URL
Error message when an invalid url is used.- See Also:
- Constant Field Values
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ERROR_NO_HOST_IN_URL
Error message when no hostname in url.- See Also:
- Constant Field Values
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METHOD_NAME
Deprecated.Since 1.10.6The method name to look for in InetAddress- See Also:
- Constant Field Values
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Constructor Details
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IsReachable
public IsReachable()
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Method Details
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setHost
Set the host to ping.- Parameters:
host- the host to ping.
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setUrl
Set the URL from which to extract the hostname.- Parameters:
url- a URL object.
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setTimeout
public void setTimeout(int timeout)Set the timeout for the reachability test in seconds.- Parameters:
timeout- the timeout in seconds.
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eval
Evaluate the condition.- Specified by:
evalin interfaceCondition- Returns:
- true if the condition is true.
- Throws:
BuildException- if an error occurs
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