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interface ValueAdapter<V>
An adapter that translates between database entries (key, primary key, data) and a "value", which may be either the key, primary key, or entity. This interface is used to implement a generic index and cursor (BasicIndex and BasicCursor). If we didn't use this approach, we would need separate index and cursor implementations for each type of value that can be returned. In other words, this interface is used to reduce class explosion.
Method Summary | |
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void |
clearEntries(DatabaseEntry key,
DatabaseEntry pkey,
DatabaseEntry data)
Sets the data array of the given entries to null, based on knowledge of which entries are non-null and are not NO_RETURN_ENTRY. |
V |
entryToValue(DatabaseEntry key,
DatabaseEntry pkey,
DatabaseEntry data)
Returns the appropriate "value" (key, primary key, or entity) using the appropriate bindings for that purpose. |
DatabaseEntry |
initData()
Creates a DatabaseEntry for the data or returns null if the data is not needed. |
DatabaseEntry |
initKey()
Creates a DatabaseEntry for the key or returns null if the key is not needed. |
DatabaseEntry |
initPKey()
Creates a DatabaseEntry for the primary key or returns null if the primary key is not needed. |
void |
valueToData(V value,
DatabaseEntry data)
Converts an entity value to a data entry using an entity binding, or throws UnsupportedOperationException if this is not appropriate. |
Method Detail |
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DatabaseEntry initKey()
DatabaseEntry initPKey()
DatabaseEntry initData()
void clearEntries(DatabaseEntry key, DatabaseEntry pkey, DatabaseEntry data)
V entryToValue(DatabaseEntry key, DatabaseEntry pkey, DatabaseEntry data)
void valueToData(V value, DatabaseEntry data)
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