org.hd.d.pg2k.svrCore
Class ExhibitPropsGlobalImmutable

java.lang.Object
  org.hd.d.pg2k.svrCore.ExhibitPropsGlobalImmutable

All Implemented Interfaces:

java.io.Serializable

public final class ExhibitPropsGlobalImmutable
extends java.lang.Object
implements java.io.Serializable

This contains global immutable exhibit data over all exhibits that must live with the exhibits. This is data that does not apply to any one exhibit but is small and critical to handling of all exhibits.

Currently this contains:

• The AEP-attached location DB properties.
• The prefix translations and comments and aliases (tree description).

This can include:

• tree-structured (i18n-ed) info
• hot/cold lists
• see-also lists (links)
• vote history

This has a hash computed over its contents to make it easy for users of this object to tell if it has changed since previous incarnations.

This object is immutable and Serializable, and tries to validate its contents upon deserialisation.

See Also:

Serialized Form

locationDBTimestamp

public final long locationDBTimestamp

The location DB timestamp; strictly positive, or zero if no/empty locationDB.

locationDB

private final PropertiesDiff locationDB

The (immutable) location DB in properties format; null if absent. We store this in PropertiesDiff format for efficiency on the wire, but convert it to LocationMap before use.

May be absent if there was no location data available at AEP creation or when deserialising an older AEP that has no location data, or as a more efficient way to represent an empty value (we always store an empty value as null for efficiency).

treedescTimestamp

public final long treedescTimestamp

The treedesc bundle timestamp; non-negative, or may be zero if locationDBis empty/absent.

treedesc

private final PropertiesBundleDiff treedesc

The (immutable) treedesc bundle; null if absent. We store this in PropertiesBundleDiff format for efficiency on the wire.

May be absent if there was no location data available at AEP creation or when deserialising an older AEP that has no location data, or as a more efficient way to represent an empty value (we always store an empty value as null for efficiency).

locMap

private transient volatile LocationMap locMap

The (immutable) LocationMap derived from the locationDB; never null. Created on or before first use.

Derived from the locationDB info, empty if no locationDB.

Not part of the serialised state.

Marked volatile for lock-free thread-safe access.

longHash

public final long longHash

The hash of all the data held; guaranteed non-negative. Depends all the information held in this object.

Will be zero if this contains no data.

serialVersionUID

private static final long serialVersionUID

Our serial version...

See Also:

Constant Field Values

ExhibitPropsGlobalImmutable

public ExhibitPropsGlobalImmutable()

Create an empty instance.

ExhibitPropsGlobalImmutable

public ExhibitPropsGlobalImmutable(java.util.Properties locationDB,
                                   long locationDBTimestamp,
                                   java.util.Map<java.lang.String,java.util.Properties> treedesc,
                                   long treedescTimestamp)

Create an instance.

ExhibitPropsGlobalImmutable

public ExhibitPropsGlobalImmutable(PropertiesDiff locationDB,
                                   long locationDBTimestamp,
                                   PropertiesBundleDiff treedesc,
                                   long treedescTimestamp)

Create an instance.

loadFromDataDir

public static ExhibitPropsGlobalImmutable loadFromDataDir(java.io.File exhibitDataDir)
                                                   throws java.io.IOException

Load global data from filesystem.

Throws:

java.io.IOException

getTreedescHash

public final int getTreedescHash()

Get the hash of the treedesc; non-negative, or may be zero if treedesc is empty/absent.

getLocationMap

public LocationMap getLocationMap()

Get the LocationMap; never null.

getLocalisedTreeDescMessage

public java.lang.CharSequence getLocalisedTreeDescMessage(java.lang.String msgName,
                                                          java.util.Locale locale)

Gets the appropriate localised tree-description message; never null unless the key is null. In case of a missing message, or unavailable treedesc data, this returns the key itself.

The key is converted to lower-case (if necessary) before lookup.

If the name is null, the result is null.

Parameters:

locale - desired locale, or null

hashCode

public int hashCode()

Returns a hash code value for the object; derived from the longHash. Guaranteed zero if there are no exhibits.

Overrides:

hashCode in class java.lang.Object

Returns:

a hash code value for this object.

equals

public boolean equals(java.lang.Object obj)

Indicates whether some other object is "equal to" this one; the underlying data is the same if true.

Overrides:

equals in class java.lang.Object

Parameters:

obj - the reference object with which to compare.

Returns:

true if this object is the same as the obj argument; false otherwise.

toString

public java.lang.String toString()

Human-readable summary of state.

Overrides:

toString in class java.lang.Object

validateObject

public void validateObject()
                    throws java.io.InvalidObjectException

Validate fields/state. Called in the constructor and possibly after de-serialising.

Barf if something bad is found. (Maybe allow some extra info in debug version.)

Throws:

java.io.InvalidObjectException

readResolve

protected java.lang.Object readResolve()
                                throws java.io.ObjectStreamException

Deserialise: use constructor for validation, defensive copying, conversion from old formats, etc. Also allows us to (re)normalise the data in this instance, eg to recompute the longHash in case our hash algorithm changes.

Throws:

java.io.ObjectStreamException