Package org.apache.openjpa.jdbc.meta

Interface ValueHandler

All Superinterfaces:

java.io.Serializable

All Known Implementing Classes:

AbstractValueHandler, BlobValueHandler, ByteArrayValueHandler, CharArrayStreamValueHandler, CharArrayValueHandler, ClobValueHandler, ElementEmbedValueHandler, EmbedValueHandler, EnumValueHandler, ImmutableValueHandler, ObjectIdValueHandler, UntypedPCValueHandler, XMLValueHandler

public interface ValueHandler
extends java.io.Serializable

Maps a value to a relational schema. Value handler are stateless.

Since:

0.4.0

Author:

Abe White

Method Summary

Modifier and Type	Method	Description
java.lang.Object	getResultArgument(ValueMapping vm)	Return the argument to pass to the result set when loading data via Result.getObject(java.lang.Object, int, java.lang.Object), or null if none.
boolean	isVersionable(ValueMapping vm)	Return whether the values managed by this handler can be used in state image versioning.
Column[]	map(ValueMapping vm, java.lang.String name, ColumnIO io, boolean adapt)	Map the given value and return all mapped columns, or simply return an array of unmapped default columns.
boolean	objectValueRequiresLoad(ValueMapping vm)	Return whether this handler potentially must load extra data to extract the object value from its datastore representation.
java.lang.Object	toDataStoreValue(ValueMapping vm, java.lang.Object val, JDBCStore store)	Translate the given value to its datastore equivalent.
java.lang.Object	toObjectValue(ValueMapping vm, java.lang.Object val)	Translate the given datastore value into its Java equivalent.
java.lang.Object	toObjectValue(ValueMapping vm, java.lang.Object val, OpenJPAStateManager sm, JDBCStore store, JDBCFetchConfiguration fetch)	Translate the given datastore value into its Java equivalent.

Method Detail

map

Column[] map(ValueMapping vm,
             java.lang.String name,
             ColumnIO io,
             boolean adapt)

Map the given value and return all mapped columns, or simply return an array of unmapped default columns. The columns should have at least their Name and JavaType properties set.

Parameters:

name - use as a base to form column name(s); the column names of unmapped columns will automatically be made to fit database limitations

io - I/O information about mapped columns; you do not have to set this information if returning templates

adapt - whether to adapt the mapping or schema

isVersionable

boolean isVersionable(ValueMapping vm)

Return whether the values managed by this handler can be used in state image versioning.

objectValueRequiresLoad

boolean objectValueRequiresLoad(ValueMapping vm)

Return whether this handler potentially must load extra data to extract the object value from its datastore representation.

getResultArgument

java.lang.Object getResultArgument(ValueMapping vm)

Return the argument to pass to the result set when loading data via Result.getObject(java.lang.Object, int, java.lang.Object), or null if none. If this value occupies multiple columns, return an array with one element per column. You may return null if all array elements would be null.

toDataStoreValue

java.lang.Object toDataStoreValue(ValueMapping vm,
                                  java.lang.Object val,
                                  JDBCStore store)

Translate the given value to its datastore equivalent. If this value occupies multiple columns, return an object array with one element per column. For relation id columns, return the state manager the column depends on.

toObjectValue

java.lang.Object toObjectValue(ValueMapping vm,
                               java.lang.Object val)

Translate the given datastore value into its Java equivalent. If the value occupies multiple columns, the given object will be an object array with one entry per column. This method is only called if objectValueRequiresLoad(org.apache.openjpa.jdbc.meta.ValueMapping) returns false.

toObjectValue

java.lang.Object toObjectValue(ValueMapping vm,
                               java.lang.Object val,
                               OpenJPAStateManager sm,
                               JDBCStore store,
                               JDBCFetchConfiguration fetch)
                        throws java.sql.SQLException

Translate the given datastore value into its Java equivalent. If the value occupies multiple columns, the given object will be an object array with one entry per column. This method is only called if objectValueRequiresLoad(org.apache.openjpa.jdbc.meta.ValueMapping) returns true.

Parameters:

sm - the state manager that owns the value; may be null if loading a projection

Throws:

java.sql.SQLException