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

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static interface` | `NamedSPILoader.NamedSPI` Interface to support `lookup(String)` by name.

  - ### Constructor Summary

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

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `Set<String>` | `availableServices()`
    `static void` | `checkServiceName(String name)` Validates that a service name meets the requirements of `NamedSPILoader.NamedSPI`
    `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`

- - ### Constructor Detail

    - #### NamedSPILoader

          public NamedSPILoader(Class<S> clazz)

    - #### NamedSPILoader

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

  - ### Method Detail

    - #### 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`

    - #### 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>`

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