Extension (Protocol Buffers [Core] 3.21.12 API)

java.lang.Object
- com.google.protobuf.ExtensionLite<ContainingType,Type>
- - com.google.protobuf.Extension<ContainingType,Type>

Direct Known Subclasses:

GeneratedMessage.GeneratedExtension
```
public abstract class Extension<ContainingType extends MessageLite,Type>
extends ExtensionLite<ContainingType,Type>
```
Interface that generated extensions implement.

Author:

liujisi@google.com (Jisi Liu)

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`protected static class`	`Extension.ExtensionType`	The API type that the extension is used for.
`static class`	`Extension.MessageType`	Type of a message extension.

Constructor Summary

Constructors
Constructor Description

Extension()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`protected abstract Object`	`fromReflectionType(Object value)`
`abstract Descriptors.FieldDescriptor`	`getDescriptor()`	Returns the descriptor of the extension.
`protected abstract Extension.ExtensionType`	`getExtensionType()`
`abstract Message`	`getMessageDefaultInstance()`	Returns the default instance of the extension field, if it's a message extension.
`Extension.MessageType`	`getMessageType()`	If the extension is a message extension (i.e., getLiteType() == MESSAGE), returns the type of the message, otherwise undefined.
`protected abstract Object`	`singularFromReflectionType(Object value)`
`protected abstract Object`	`singularToReflectionType(Object value)`
`protected abstract Object`	`toReflectionType(Object value)`

Methods inherited from class com.google.protobuf.ExtensionLite
getDefaultValue, getLiteType, getNumber, isRepeated

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - Extension
```
public Extension()
```
- Method Detail
  - getMessageDefaultInstance
```
public abstract Message getMessageDefaultInstance()
```
    Returns the default instance of the extension field, if it's a message extension. Overridden to return Message instead of MessageLite.
    
    Specified by:
    
    getMessageDefaultInstance in class ExtensionLite<ContainingType extends MessageLite,Type>
  - getDescriptor
```
public abstract Descriptors.FieldDescriptor getDescriptor()
```
    Returns the descriptor of the extension.
  - getExtensionType
```
protected abstract Extension.ExtensionType getExtensionType()
```
  - getMessageType
```
public Extension.MessageType getMessageType()
```
    If the extension is a message extension (i.e., getLiteType() == MESSAGE), returns the type of the message, otherwise undefined.
  - fromReflectionType
```
protected abstract Object fromReflectionType(Object value)
```
  - singularFromReflectionType
```
protected abstract Object singularFromReflectionType(Object value)
```
  - toReflectionType
```
protected abstract Object toReflectionType(Object value)
```
  - singularToReflectionType
```
protected abstract Object singularToReflectionType(Object value)
```