com.persistit.encoding

Interface KeyRenderer

All Superinterfaces:

KeyCoder

All Known Subinterfaces:

ObjectCoder

All Known Implementing Classes:

DefaultObjectCoder

public interface KeyRenderer
extends KeyCoder

An extended KeyCoder that can populate a supplied Object with data that was formerly written to a Key by the KeyCoder .

A KeyRenderer implements an additional method called renderKeySegment(com.persistit.Key, java.lang.Object, java.lang.Class<?>, com.persistit.encoding.CoderContext) that populates a supplied target object rather than creating a new object instance.

Version:

1.0

Method Summary

Modifier and Type	Method and Description
void	renderKeySegment(Key key, Object target, Class<?> clazz, CoderContext context) Populate the state of the supplied target Object by decoding the next key segment of the supplied Key.

Methods inherited from interface com.persistit.encoding.KeyCoder

appendKeySegment, decodeKeySegment, isZeroByteFree

Method Detail

renderKeySegment

void renderKeySegment(Key key,
                      Object target,
                      Class<?> clazz,
                      CoderContext context)
               throws ConversionException

Populate the state of the supplied target Object by decoding the next key segment of the supplied Key. This method will be called only if this KeyRenderer has been registered with the current CoderManager to encode objects having the supplied Class value. In addition, Persistit will never call this method to decode a value that was null when written because null values are handled by built-in encoding logic.

When this method is called the value Key.getIndex() will be the offset within the key of the first encoded byte. The key segment is zero-byte terminated.

Parameters:

key - The Key from which interior fields of the object are to be retrieved

target - An object into which the key segment is to be written

clazz - The class of the object that was originally encoded into Value.

context - An arbitrary object that can optionally be supplied by the application to convey an application-specific context for the operation. (See CoderContext.) The default value is null.

Throws:

ConversionException