Package org.exoplatform.caldav.utils

Class ServerQuirkSummary

java.lang.Object

org.exoplatform.caldav.utils.ServerQuirkSummary

public final class ServerQuirkSummary
extends Object

Reads and writes the rolling summary of what a server has been seen doing, stored as one string on its registration row.

The format is deliberately trivial — DIRECTION:PROPERTY=COUNT@LASTSEEN, entries separated by ;, where the stamp is an epoch day. It has to be read by whoever opens the row in a database client while diagnosing a server, and a JSON blob in a column is read by nobody. It also has to survive being written by an older build and read by a newer one, which it does the only way a format this small can: an entry that cannot be read is dropped and the rest of the summary still parses. An entry written before the stamp existed simply has none, and ServerQuirkSummary.Tally.UNKNOWN_DAY says so rather than pretending to a date.

Bounded, because a column is not a log. At most MAX_ENTRIES entries survive a write, the largest counts first, so a server producing a new proprietary property on every copy cannot grow the row without limit. Property names are truncated to MAX_PROPERTY — a name longer than that is not a property name anybody will act on, and the column has a length.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final record	ServerQuirkSummary.Observation	One thing a server was seen doing, as the summary keys it.
static final record	ServerQuirkSummary.Retention	What a summary is allowed to forget on one write.
static final record	ServerQuirkSummary.Tally	How often a behaviour has been seen, and when it was last seen.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	MAX_ENTRIES	How many observations one server's summary keeps.
static final int	MAX_PROPERTY	How much of a property name is kept.

Method Summary

Modifier and Type	Method	Description
static String	format(Map<ServerQuirkSummary.Observation,ServerQuirkSummary.Tally> observations)	Writes a summary back, largest counts first and bounded in both directions.
static Map<ServerQuirkSummary.Observation,ServerQuirkSummary.Tally>	parse(String summary)	Reads a stored summary.

Methods inherited from class java.lang.Object

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

Field Details

MAX_ENTRIES

public static final int MAX_ENTRIES

How many observations one server's summary keeps.

See Also:

• Constant Field Values

MAX_PROPERTY

public static final int MAX_PROPERTY

How much of a property name is kept.

See Also:

• Constant Field Values

Method Details

parse

public static Map<ServerQuirkSummary.Observation,ServerQuirkSummary.Tally> parse(String summary)

Reads a stored summary.

Never throws: this parses a value a previous build wrote, and a summary that cannot be read must leave the drawer showing less rather than leave the registration unreadable. An unreadable entry is dropped on its own.

Parameters:

summary - the stored value, may be null or blank

Returns:

the observations and their counts, in the order they were stored, never null

format

public static String format(Map<ServerQuirkSummary.Observation,ServerQuirkSummary.Tally> observations)

Writes a summary back, largest counts first and bounded in both directions.

Parameters:

observations - the observations and their counts

Returns:

the value to store, null when there is nothing to store