gov.nasa.worldwind.util

Class BasicNetworkStatus

java.lang.Object

gov.nasa.worldwind.avlist.AVListImpl

gov.nasa.worldwind.util.BasicNetworkStatus

All Implemented Interfaces:

AVList, NetworkStatus

public class BasicNetworkStatus
extends AVListImpl
implements NetworkStatus

Basic implementation of NetworkStatus.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	BasicNetworkStatus.HostInfo

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	DEFAULT_ATTEMPT_LIMIT
protected static String[]	DEFAULT_NETWORK_TEST_SITES
protected static long	DEFAULT_TRY_AGAIN_INTERVAL
protected ConcurrentHashMap<String,BasicNetworkStatus.HostInfo>	hostMap
protected AtomicLong	lastAvailableLogTime
protected AtomicLong	lastNetworkCheckTime
protected AtomicLong	lastNetworkStatusReportTime
protected AtomicBoolean	lastNetworkUnavailableResult
protected AtomicLong	lastUnavailableLogTime
protected static long	NETWORK_STATUS_REPORT_INTERVAL

Fields inherited from interface gov.nasa.worldwind.util.NetworkStatus

HOST_AVAILABLE, HOST_UNAVAILABLE

Constructor Summary

Constructors

Constructor and Description
BasicNetworkStatus()

Method Summary

Modifier and Type	Method and Description
protected void	establishNetworkTestSites() Determines and stores the network sites to test for public network connectivity.
int	getAttemptLimit() Returns the number of times a host must be logged as unavailable before it is marked unavailable in this class.
List<String>	getNetworkTestSites() Returns the server domain names of the sites used to test public network availability.
long	getTryAgainInterval() Returns the length of time to wait until a host is marked as not unreachable subsequent to its being marked unreachable.
protected static boolean	isHostReachable(String hostName) Determine if a host is reachable by attempting to resolve the host name, and then attempting to open a connection.
boolean	isHostUnavailable(URL url) Indicates whether the host has been marked as unavailable.
boolean	isNetworkUnavailable() Indicates whether a public network can be reached or has been reached in the previous five seconds.
boolean	isNetworkUnavailable(long checkInterval) Indicates whether a public network can be reached or has been reached in a specified previous amount of time.
boolean	isOfflineMode() Indicates whether World Wind will attempt to connect to the network to retrieve data or for other reasons.
boolean	isWorldWindServerUnavailable() Indicates whether the NASA World Wind servers can be reached.
void	logAvailableHost(URL url) Log a host as available.
void	logUnavailableHost(URL url) Log a host as unavailable.
void	setAttemptLimit(int limit) Sets the number of times a host must be logged as unavailable before it is marked unavailable in this class.
void	setNetworkTestSites(List<String> networkTestSites) Sets the domain names, e.g., worldwind.arc.nasa.gov, of sites used to determine public network availability.
void	setOfflineMode(boolean offlineMode) Indicates whether World Wind should attempt to connect to the network to retrieve data or for other reasons.
void	setTryAgainInterval(long interval) Sets the length of time to wait until a host is marked as not unreachable subsequent to its being marked unreachable.

Methods inherited from class gov.nasa.worldwind.avlist.AVListImpl

addPropertyChangeListener, addPropertyChangeListener, clearList, copy, firePropertyChange, firePropertyChange, getBooleanValue, getBooleanValue, getChangeSupport, getDoubleValue, getDoubleValue, getEntries, getIntegerValue, getIntegerValue, getLongValue, getLongValue, getRestorableStateForAVPair, getStringValue, getStringValue, getStringValue, getValue, getValues, hasKey, removeKey, removePropertyChangeListener, removePropertyChangeListener, setValue, setValues

Methods inherited from class java.lang.Object

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

Methods inherited from interface gov.nasa.worldwind.avlist.AVList

addPropertyChangeListener, addPropertyChangeListener, clearList, copy, firePropertyChange, firePropertyChange, getEntries, getStringValue, getValue, getValues, hasKey, removeKey, removePropertyChangeListener, removePropertyChangeListener, setValue, setValues

Field Detail

DEFAULT_ATTEMPT_LIMIT

protected static final int DEFAULT_ATTEMPT_LIMIT

See Also:

Constant Field Values

DEFAULT_NETWORK_TEST_SITES

protected static final String[] DEFAULT_NETWORK_TEST_SITES

DEFAULT_TRY_AGAIN_INTERVAL

protected static final long DEFAULT_TRY_AGAIN_INTERVAL

See Also:

Constant Field Values

hostMap

protected ConcurrentHashMap<String,BasicNetworkStatus.HostInfo> hostMap

lastAvailableLogTime

protected AtomicLong lastAvailableLogTime

lastNetworkCheckTime

protected AtomicLong lastNetworkCheckTime

lastNetworkStatusReportTime

protected AtomicLong lastNetworkStatusReportTime

lastNetworkUnavailableResult

protected AtomicBoolean lastNetworkUnavailableResult

lastUnavailableLogTime

protected AtomicLong lastUnavailableLogTime

NETWORK_STATUS_REPORT_INTERVAL

protected static final long NETWORK_STATUS_REPORT_INTERVAL

See Also:

Constant Field Values

Constructor Detail

BasicNetworkStatus

public BasicNetworkStatus()

Method Detail

establishNetworkTestSites

protected void establishNetworkTestSites()

Determines and stores the network sites to test for public network connectivity. The sites are drawn from the JVM's gov.nasa.worldwind.avkey.NetworkStatusTestSites property (AVKey.NETWORK_STATUS_TEST_SITES). If that property is not defined, the sites are drawn from the same property in the World Wind or application configuration file. If the sites are not specified there, the set of sites specified in DEFAULT_NETWORK_TEST_SITES are used. To indicate an empty list in the JVM property or configuration file property, specify an empty site list, "".

getAttemptLimit

public int getAttemptLimit()

Returns the number of times a host must be logged as unavailable before it is marked unavailable in this class.

Specified by:

getAttemptLimit in interface NetworkStatus

Returns:

the limit.

getNetworkTestSites

public List<String> getNetworkTestSites()

Returns the server domain names of the sites used to test public network availability.

Specified by:

getNetworkTestSites in interface NetworkStatus

Returns:

the list of sites used to check network status. The list is a copy of the internal list, so changes to it do not affect instances of this class.

getTryAgainInterval

public long getTryAgainInterval()

Returns the length of time to wait until a host is marked as not unreachable subsequent to its being marked unreachable.

Specified by:

getTryAgainInterval in interface NetworkStatus

Returns:

the interval, in milliseconds.

isHostReachable

protected static boolean isHostReachable(String hostName)

Determine if a host is reachable by attempting to resolve the host name, and then attempting to open a connection.

Parameters:

hostName - Name of the host to connect to.

Returns:

true if a the host is reachable, false if the host name cannot be resolved, or if opening a connection to the host fails.

isHostUnavailable

public boolean isHostUnavailable(URL url)

Indicates whether the host has been marked as unavailable. To be marked unavailable a host's attempt count must exceed the specified attempt limit.

Specified by:

isHostUnavailable in interface NetworkStatus

Parameters:

url - a url containing the host to check for availability.

Returns:

true if the host is marked as unavailable, otherwise false.

isNetworkUnavailable

public boolean isNetworkUnavailable()

Indicates whether a public network can be reached or has been reached in the previous five seconds.

Specified by:

isNetworkUnavailable in interface NetworkStatus

Returns:

false if the network can be reached or has been reached in the previous five seconds, otherwise true.

isNetworkUnavailable

public boolean isNetworkUnavailable(long checkInterval)

Indicates whether a public network can be reached or has been reached in a specified previous amount of time.

Specified by:

isNetworkUnavailable in interface NetworkStatus

Parameters:

checkInterval - the number of milliseconds in the past used to determine whether the server was avaialble recently.

Returns:

false if the network can be reached or has been reached in a specified time, otherwise true.

isOfflineMode

public boolean isOfflineMode()

Indicates whether World Wind will attempt to connect to the network to retrieve data or for other reasons.

Specified by:

isOfflineMode in interface NetworkStatus

Returns:

true if World Wind is in off-line mode, false if not.

isWorldWindServerUnavailable

public boolean isWorldWindServerUnavailable()

Indicates whether the NASA World Wind servers can be reached.

Specified by:

isWorldWindServerUnavailable in interface NetworkStatus

Returns:

false if the servers can be reached, otherwise true.

logAvailableHost

public void logAvailableHost(URL url)

Log a host as available. Each invocation causes the host to no longer be marked as unavailable. Its unavailability count is effectively set to 0.

Specified by:

logAvailableHost in interface NetworkStatus

Parameters:

url - a url containing the host to mark as available.

logUnavailableHost

public void logUnavailableHost(URL url)

Log a host as unavailable. Each invocation increments the host's attempt count. When the count equals or exceeds the attempt limit, the host is marked as unavailable.

Specified by:

logUnavailableHost in interface NetworkStatus

Parameters:

url - a url containing the host to mark as unavailable.

setAttemptLimit

public void setAttemptLimit(int limit)

Sets the number of times a host must be logged as unavailable before it is marked unavailable in this class.

Specified by:

setAttemptLimit in interface NetworkStatus

Parameters:

limit - the number of log-unavailability invocations necessary to consider the host unreachable.

setNetworkTestSites

public void setNetworkTestSites(List<String> networkTestSites)

Sets the domain names, e.g., worldwind.arc.nasa.gov, of sites used to determine public network availability.

Specified by:

setNetworkTestSites in interface NetworkStatus

Parameters:

networkTestSites - the list of desired test sites. The list is copied internally, so changes made to the submitted list do not affect instances of this class. May be null, in which case no sites are consulted.

setOfflineMode

public void setOfflineMode(boolean offlineMode)

Indicates whether World Wind should attempt to connect to the network to retrieve data or for other reasons. The default value for this attribute is false, indicating that the network should be used.

Specified by:

setOfflineMode in interface NetworkStatus

Parameters:

offlineMode - true if World Wind should use the network, false otherwise

setTryAgainInterval

public void setTryAgainInterval(long interval)

Sets the length of time to wait until a host is marked as not unreachable subsequent to its being marked unreachable.

Specified by:

setTryAgainInterval in interface NetworkStatus

Parameters:

interval - The length of time, in milliseconds, to wait to unmark a host as unreachable.