To finally answer the title question: It is (a client side setting) in (project, profile or settings)
[plugin]?[r|R]epository/[releases|snapshots]/updatePolicy
... tag.
The (currently, maven: 3.6.0, but I suppose "far backwards" compatible) possible values are :
/**
* Never update locally cached data.
*/
public static final String UPDATE_POLICY_NEVER = "never";
/**
* Always update locally cached data.
*/
public static final String UPDATE_POLICY_ALWAYS = "always";
/**
* Update locally cached data once a day.
*/
public static final String UPDATE_POLICY_DAILY = "daily";
/**
* Update locally cached data **every X minutes** as given by "interval:X".
*/
public static final String UPDATE_POLICY_INTERVAL = "interval";
The current (maven 3.6.0) evaluation of this tag is implemented as follows:
public boolean isUpdatedRequired( RepositorySystemSession session, long lastModified, String policy )
{
boolean checkForUpdates;
if ( policy == null )
{
policy = "";
}
if ( RepositoryPolicy.UPDATE_POLICY_ALWAYS.equals( policy ) )
{
checkForUpdates = true;
}
else if ( RepositoryPolicy.UPDATE_POLICY_DAILY.equals( policy ) )
{
Calendar cal = Calendar.getInstance();
cal.set( Calendar.HOUR_OF_DAY, 0 );
cal.set( Calendar.MINUTE, 0 );
cal.set( Calendar.SECOND, 0 );
cal.set( Calendar.MILLISECOND, 0 );
checkForUpdates = cal.getTimeInMillis() > lastModified;
}
else if ( policy.startsWith( RepositoryPolicy.UPDATE_POLICY_INTERVAL ) )
{
int minutes = getMinutes( policy );
Calendar cal = Calendar.getInstance();
cal.add( Calendar.MINUTE, -minutes );
checkForUpdates = cal.getTimeInMillis() > lastModified;
}
else
{
// assume "never"
checkForUpdates = false;
if ( !RepositoryPolicy.UPDATE_POLICY_NEVER.equals( policy ) )
{
LOGGER.warn( "Unknown repository update policy '{}', assuming '{}'",
policy, RepositoryPolicy.UPDATE_POLICY_NEVER );
}
}
return checkForUpdates;
}
..with:
private int getMinutes( String policy )
{
int minutes;
try
{
String s = policy.substring( RepositoryPolicy.UPDATE_POLICY_INTERVAL.length() + 1 );
minutes = Integer.valueOf( s );
}
catch ( RuntimeException e )
{
minutes = 24 * 60;
LOGGER.warn( "Non-parseable repository update policy '{}', assuming '{}:1440'",
policy, RepositoryPolicy.UPDATE_POLICY_INTERVAL );
}
return minutes;
}
...where lastModified is the (local file) "modified timestamp" of an/each underlying artifact.
In particular for the interval:x setting:
- the colon
: is not that strict - any "non-empty" character could do it (=,
- negative values
x < 0 should yield to "never".
interval:0 I would assume a "minutely" (0-59 secs. or above...) interval.- number format exceptions result in
24 * 60 minutes (~"daily").
..see: DefaultUpdatePolicyAnalyzer, DefaultMetadataResolver#resolveMetadata() and RepositoryPolicy
