Package com.google.gerrit.extensions.registration

Class DynamicItem<T>

java.lang.Object
com.google.gerrit.extensions.registration.DynamicItem<T>
public class DynamicItem<T> extends Object
A single item that can be modified as plugins reload.

DynamicItems are always mapped as singletons in Guice. Items store a Provider internally, and resolve the provider to an instance on demand. This enables registrations to decide between singleton and non-singleton members. If multiple plugins try to provide the same Provider, an exception is thrown.

  • Method Summary

    Modifier and Type
    Method
    Description
    static <T> com.google.inject.binder.LinkedBindingBuilder<T>
    bind(com.google.inject.Binder binder, com.google.inject.TypeLiteral<T> type)
    Bind one implementation as the item.
    static <T> com.google.inject.binder.LinkedBindingBuilder<T>
    bind(com.google.inject.Binder binder, Class<T> type)
    Bind one implementation as the item using a unique annotation.
    T
    get()
    Get the configured item, or null.
    Extension<T>
    getEntry()
     
    String
    getPluginName()
    Get the name of the plugin that has bound the configured item, or null.
    static <T> void
    itemOf(com.google.inject.Binder binder, com.google.inject.TypeLiteral<T> member)
    Declare a singleton DynamicItem<T> with a binder.
    static <T> void
    itemOf(com.google.inject.Binder binder, Class<T> member)
    Declare a singleton DynamicItem<T> with a binder.
    static <T> DynamicItem<T>
    itemOf(Class<T> member, T item)
    Construct a single DynamicItem<T> with a fixed value.
    ReloadableRegistrationHandle<T>
    set(com.google.inject.Key<T> key, com.google.inject.Provider<T> impl, String pluginName)
    Set the element that may be hot-replaceable in the future.
    RegistrationHandle
    set(com.google.inject.Provider<T> impl, String pluginName)
    Set the element to provide.
    RegistrationHandle
    set(T item, String pluginName)
    Set the element to provide.

    Methods inherited from class java.lang.Object

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

  • Method Details

    • itemOf

      public static <T> void itemOf(com.google.inject.Binder binder, Class<T> member)
      Declare a singleton DynamicItem<T> with a binder.

      Items must be defined in a Guice module before they can be bound: 

         DynamicItem.itemOf(binder(), Interface.class);
   DynamicItem.bind(binder(), Interface.class).to(Impl.class);
      Parameters:
      binder - a new binder created in the module.
      member - type of entry to store.

    • itemOf

      public static <T> void itemOf(com.google.inject.Binder binder, com.google.inject.TypeLiteral<T> member)
      Declare a singleton DynamicItem<T> with a binder.

      Items must be defined in a Guice module before they can be bound: 

         DynamicSet.itemOf(binder(), new TypeLiteral<Thing<Foo>>() {});
      Parameters:
      binder - a new binder created in the module.
      member - type of entry to store.

    • itemOf

      public static <T> DynamicItem<T> itemOf(Class<T> member, T item)
      Construct a single DynamicItem<T> with a fixed value.

      Primarily useful for passing DynamicItems to constructors in tests.

      Parameters:
      member - type of item.
      item - item to store.

    • bind

      public static <T> com.google.inject.binder.LinkedBindingBuilder<T> bind(com.google.inject.Binder binder, Class<T> type)
      Bind one implementation as the item using a unique annotation.
      Parameters:
      binder - a new binder created in the module.
      type - type of entry to store.
      Returns:
      a binder to continue configuring the new item.

    • bind

      public static <T> com.google.inject.binder.LinkedBindingBuilder<T> bind(com.google.inject.Binder binder, com.google.inject.TypeLiteral<T> type)
      Bind one implementation as the item.
      Parameters:
      binder - a new binder created in the module.
      type - type of entry to store.
      Returns:
      a binder to continue configuring the new item.

    • getEntry

      public Extension<T> getEntry()

    • get

      public T get()
      Get the configured item, or null.
      Returns:
      the configured item instance; null if no implementation has been bound to the item. This is common if no plugin registered an implementation for the type.

    • getPluginName

      public String getPluginName()
      Get the name of the plugin that has bound the configured item, or null.
      Returns:
      the name of the plugin that has bound the configured item; null if no implementation has been bound to the item. This is common if no plugin registered an implementation for the type.

    • set

      public RegistrationHandle set(T item, String pluginName)
      Set the element to provide.
      Parameters:
      item - the item to use. Must not be null.
      pluginName - the name of the plugin providing the item.
      Returns:
      handle to remove the item at a later point in time.

    • set

      public RegistrationHandle set(com.google.inject.Provider<T> impl, String pluginName)
      Set the element to provide.
      Parameters:
      impl - the item to add to the collection. Must not be null.
      pluginName - name of the source providing the implementation.
      Returns:
      handle to remove the item at a later point in time.

    • set

      public ReloadableRegistrationHandle<T> set(com.google.inject.Key<T> key, com.google.inject.Provider<T> impl, String pluginName)
      Set the element that may be hot-replaceable in the future.
      Parameters:
      key - unique description from the item's Guice binding. This can be later obtained from the registration handle to facilitate matching with the new equivalent instance during a hot reload.
      impl - the item to set as our value right now. Must not be null.
      pluginName - the name of the plugin providing the item.
      Returns:
      a handle that can remove this item later, or hot-swap the item.