Package org.apache.lucene.index

Class SortFieldProvider

java.lang.Object

org.apache.lucene.index.SortFieldProvider

All Implemented Interfaces:

NamedSPILoader.NamedSPI

Direct Known Subclasses:

SortedNumericSortField.Provider, SortedSetSortField.Provider, SortField.Provider

public abstract class SortFieldProvider
extends Object
implements NamedSPILoader.NamedSPI

Reads/Writes a named SortField from a segment info file, used to record index sorts

Field Summary

Fields

Modifier and Type	Field	Description
protected String	name	The name this SortFieldProvider is registered under

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SortFieldProvider(String name)	Creates a new SortFieldProvider.

Method Summary

Modifier and Type	Method	Description
static Set<String>	availableSortFieldProviders()	Lists all available SortFieldProviders
static SortFieldProvider	forName(String name)	Looks up a SortFieldProvider by name
String	getName()
abstract SortField	readSortField(DataInput in)	Reads a SortField from serialized bytes
static void	reloadSortFieldProviders(ClassLoader classLoader)	Reloads the SortFieldProvider list from the given ClassLoader.
static void	write(SortField sf, DataOutput output)	Writes a SortField to a DataOutput
abstract void	writeSortField(SortField sf, DataOutput out)	Writes a SortField to a DataOutput

Methods inherited from class java.lang.Object

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

Field Detail

name

protected final String name

The name this SortFieldProvider is registered under

Constructor Detail

SortFieldProvider

protected SortFieldProvider(String name)

Creates a new SortFieldProvider.

The provided name will be written into the index segment: in order to for the segment to be read this class should be registered with Java's SPI mechanism (registered in META-INF/ of your jar file, etc).

Parameters:

name - must be all ascii alphanumeric, and less than 128 characters in length.

Method Detail

forName

public static SortFieldProvider forName(String name)

Looks up a SortFieldProvider by name

availableSortFieldProviders

public static Set<String> availableSortFieldProviders()

Lists all available SortFieldProviders

reloadSortFieldProviders

public static void reloadSortFieldProviders(ClassLoader classLoader)

Reloads the SortFieldProvider list from the given ClassLoader. Changes to the list are visible after the method ends, all iterators (availableSortFieldProviders() ()},...) stay consistent.

NOTE: Only new SortFieldProviders are added, existing ones are never removed or replaced.

This method is expensive and should only be called for discovery of new SortFieldProviders on the given classpath/classloader!

write

public static void write(SortField sf,
                         DataOutput output)
                  throws IOException

Writes a SortField to a DataOutput

Throws:

IOException

getName

public String getName()

Specified by:

getName in interface NamedSPILoader.NamedSPI

readSortField

public abstract SortField readSortField(DataInput in)
                                 throws IOException

Reads a SortField from serialized bytes

Throws:

IOException

writeSortField

public abstract void writeSortField(SortField sf,
                                    DataOutput out)
                             throws IOException

Writes a SortField to a DataOutput

This is used to record index sort information in segment headers

Throws:

IOException