org.apache.mahout.cf.taste.impl.model.file

Class FileIDMigrator

java.lang.Object

org.apache.mahout.cf.taste.impl.model.AbstractIDMigrator

org.apache.mahout.cf.taste.impl.model.file.FileIDMigrator

All Implemented Interfaces:

Refreshable, IDMigrator

public class FileIDMigrator
extends AbstractIDMigrator

An IDMigrator backed by a file. This class typically expects a file where each line contains a single stringID to be stored in this migrator.

This class will reload data from the data file when refresh(Collection) is called, unless the file has been reloaded very recently already.

Field Summary

Fields

Modifier and Type	Field and Description
static long	DEFAULT_MIN_RELOAD_INTERVAL_MS

Constructor Summary

Constructors

Constructor and Description
FileIDMigrator(File dataFile)
FileIDMigrator(File dataFile, long minReloadIntervalMS)

Method Summary

Modifier and Type	Method and Description
void	refresh(Collection<Refreshable> alreadyRefreshed) Triggers "refresh" -- whatever that means -- of the implementation.
String	toString()
String	toStringID(long longID)

Methods inherited from class org.apache.mahout.cf.taste.impl.model.AbstractIDMigrator

hash, toLongID

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_MIN_RELOAD_INTERVAL_MS

public static final long DEFAULT_MIN_RELOAD_INTERVAL_MS

See Also:

Constant Field Values

Constructor Detail

FileIDMigrator

public FileIDMigrator(File dataFile)
               throws FileNotFoundException

Throws:

FileNotFoundException

FileIDMigrator

public FileIDMigrator(File dataFile,
                      long minReloadIntervalMS)
               throws FileNotFoundException

Throws:

FileNotFoundException

Method Detail

toStringID

public String toStringID(long longID)

Returns:

the string ID most recently associated with the given long ID, or null if doesn't exist

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

Overrides:

refresh in class AbstractIDMigrator

Parameters:

alreadyRefreshed - Refreshables that are known to have already been refreshed as a result of an initial call to a {#refresh(Collection)} method on some object. This ensure that objects in a refresh dependency graph aren't refreshed twice needlessly.

toString

public String toString()

Overrides:

toString in class Object