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 and Description
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.
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.
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, Class<T> member) Declare a singleton DynamicItem<T> with a binder.
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> 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 Detail

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.