org.apache.lucene.util

Class SPIClassIterator<S>

java.lang.Object

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

All Implemented Interfaces:

Iterator<Class<? extends S>>

public final class SPIClassIterator<S>
extends Object
implements Iterator<Class<? extends S>>

Helper class for loading SPI classes from classpath (META-INF files). This is a light impl of ServiceLoader but is guaranteed to be bug-free regarding classpath order and does not instantiate or initialize the classes found.

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Method Summary

Modifier and Type	Method and Description
static <S> SPIClassIterator<S>	get(Class<S> clazz) Creates a new SPI iterator to lookup services of type clazz using the same ClassLoader as the argument.
static <S> SPIClassIterator<S>	get(Class<S> clazz, ClassLoader loader) Creates a new SPI iterator to lookup services of type clazz using the given classloader.
boolean	hasNext()
static boolean	isParentClassLoader(ClassLoader parent, ClassLoader child) Utility method to check if some class loader is a (grand-)parent of or the same as another one.
Class<? extends S>	next()
void	remove()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Method Detail

get

public static <S> SPIClassIterator<S> get(Class<S> clazz)

Creates a new SPI iterator to lookup services of type clazz using the same ClassLoader as the argument.

get

public static <S> SPIClassIterator<S> get(Class<S> clazz,
                                          ClassLoader loader)

Creates a new SPI iterator to lookup services of type clazz using the given classloader.

isParentClassLoader

public static boolean isParentClassLoader(ClassLoader parent,
                                          ClassLoader child)

Utility method to check if some class loader is a (grand-)parent of or the same as another one. This means the child will be able to load all classes from the parent, too.

If caller's codesource doesn't have enough permissions to do the check, false is returned (this is fine, because if we get a SecurityException it is for sure no parent).

hasNext

public boolean hasNext()

Specified by:

hasNext in interface Iterator<Class<? extends S>>

next

public Class<? extends S> next()

Specified by:

next in interface Iterator<Class<? extends S>>

remove

public void remove()

Specified by:

remove in interface Iterator<Class<? extends S>>