PlacementPluginFactory (Solr 9.0.0 core API)

All Superinterfaces:

ConfigurablePlugin<T>

All Known Implementing Classes:

AffinityPlacementFactory, DelegatingPlacementPluginFactory, MinimizeCoresPlacementFactory, RandomPlacementFactory, SimplePlacementFactory
```
public interface PlacementPluginFactory<T extends PlacementPluginConfig>
extends ConfigurablePlugin<T>
```
Factory implemented by client code and configured in container plugins (see ContainerPluginsApi.editAPI) allowing the creation of instances of PlacementPlugin to be used for replica placement computation.
Note: configurable factory implementations should also implement ConfigurablePlugin with the appropriate configuration bean type.

Nested Class Summary

Nested Classes
Modifier and Type Interface Description

static class PlacementPluginFactory.NoConfig
Useful type for plugins that don't use any configuration.

Field Summary

Fields
Modifier and Type Field Description

static String PLUGIN_NAME
The key in the plugins registry under which this plugin and its configuration are defined.

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`default void`	`configure(T cfg)`	Default implementation is a no-op.
`PlacementPlugin`	`createPluginInstance()`	Returns an instance of the plugin that will be repeatedly (and concurrently) called to compute placement.
`default T`	`getConfig()`	Return the configuration of the plugin.

- Field Detail
  - PLUGIN_NAME
```
static final String PLUGIN_NAME
```
    The key in the plugins registry under which this plugin and its configuration are defined.
    
    See Also:
    
    Constant Field Values
- Method Detail
  - createPluginInstance
```
PlacementPlugin createPluginInstance()
```
    Returns an instance of the plugin that will be repeatedly (and concurrently) called to compute placement. Multiple instances of a plugin can be used in parallel (for example if configuration has to change, but plugin instances with the previous configuration are still being used).
    If this method returns null then a simple default assignment strategy will be used (see SimplePlacementFactory).
  - configure
```
default void configure(T cfg)
```
    Default implementation is a no-op. Override to provide meaningful behavior if needed.
    
    Specified by:
    
    configure in interface ConfigurablePlugin<T extends PlacementPluginConfig>
    
    Parameters:
    
    cfg - value deserialized from JSON, not null.
  - getConfig
```
default T getConfig()
```
    Return the configuration of the plugin. Default implementation returns null.