Module org.apache.lucene.core

Package org.apache.lucene.util

Class NamedSPILoader<S extends NamedSPILoader.NamedSPI>

java.lang.Object

org.apache.lucene.util.NamedSPILoader<S>

All Implemented Interfaces:

Iterable<S>

public final class NamedSPILoader<S extends NamedSPILoader.NamedSPI>
extends Object
implements Iterable<S>

Helper class for loading named SPIs from classpath (e.g. Codec, PostingsFormat).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	NamedSPILoader.NamedSPI	Interface to support lookup(String) by name.

Field Summary

Fields

Modifier and Type	Field	Description
private final Class<S>	clazz
private Map<String,S>	services

Constructor Summary

Constructors

Constructor	Description
NamedSPILoader(Class<S> clazz)
NamedSPILoader(Class<S> clazz, ClassLoader classloader)

Method Summary

Modifier and Type	Method	Description
Set<String>	availableServices()
static void	checkServiceName(String name)	Validates that a service name meets the requirements of NamedSPILoader.NamedSPI
private static boolean	isLetterOrDigit(char c)	Checks whether a character is a letter or digit (ascii) which are defined in the spec.
Iterator<S>	iterator()
S	lookup(String name)
void	reload(ClassLoader classloader)	Reloads the internal SPI list from the given ClassLoader.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Details

services

private volatile Map<String,S extends NamedSPILoader.NamedSPI> services

clazz

private final Class<S extends NamedSPILoader.NamedSPI> clazz

Constructor Details

NamedSPILoader

public NamedSPILoader(Class<S> clazz)

NamedSPILoader

public NamedSPILoader(Class<S> clazz,
 ClassLoader classloader)

Method Details

reload

public void reload(ClassLoader classloader)

Reloads the internal SPI list from the given ClassLoader. Changes to the service list are visible after the method ends, all iterators (iterator(),...) stay consistent.

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

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

checkServiceName

public static void checkServiceName(String name)

Validates that a service name meets the requirements of NamedSPILoader.NamedSPI

isLetterOrDigit

private static boolean isLetterOrDigit(char c)

Checks whether a character is a letter or digit (ascii) which are defined in the spec.

lookup

public S lookup(String name)

availableServices

public Set<String> availableServices()

iterator

public Iterator<S> iterator()

Specified by:

iterator in interface Iterable<S extends NamedSPILoader.NamedSPI>