org.apache.mahout.cf.taste.impl.model
Class AbstractIDMigrator
java.lang.Object
org.apache.mahout.cf.taste.impl.model.AbstractIDMigrator
- All Implemented Interfaces:
- Refreshable, IDMigrator
- Direct Known Subclasses:
- AbstractJDBCIDMigrator, FileIDMigrator, MemoryIDMigrator
public abstract class AbstractIDMigrator
- extends Object
- implements IDMigrator
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
AbstractIDMigrator
protected AbstractIDMigrator()
hash
protected final long hash(String value)
- Returns:
- most significant 8 bytes of the MD5 hash of the string, as a long
toLongID
public long toLongID(String stringID)
- Specified by:
toLongID
in interface IDMigrator
- Returns:
- the top 8 bytes of the MD5 hash of the bytes of the given
String
's UTF-8 encoding as a
long.
refresh
public void refresh(Collection<Refreshable> alreadyRefreshed)
- Description copied from interface:
Refreshable
Triggers "refresh" -- whatever that means -- of the implementation. The general contract is that any
Refreshable
should always leave itself in a consistent, operational state, and that the refresh
atomically updates internal state from old to new.
- Specified by:
refresh
in interface Refreshable
- Parameters:
alreadyRefreshed
- Refreshable
s that are known to have already been
refreshed as a result of an initial call to a Refreshable.refresh(Collection)
method on some
object. This ensure that objects in a refresh dependency graph aren't refreshed twice
needlessly.
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