Difference between revisions of "EclipseLink/UserGuide/JPA/Basic JPA Development/Mapping/Basic Mappings/Default Conversions and Converters/TypeConverter"

From Eclipsepedia

Jump to: navigation, search
m
m
Line 16: Line 16:
 
</source>
 
</source>
 
{{EclipseLink_AttributeTable
 
{{EclipseLink_AttributeTable
|caption=<span>@TypeConverter Attributes</span>
+
|caption=<span>@TypeConverter Annotation Attributes</span>
 
|content=
 
|content=
 
<tr>
 
<tr>
Line 40: Line 40:
  
  
This example shows how to use the <tt>@TypeConverter</tt> annotation to convert the <tt>Double</tt> value stored in the database to a <tt>Float</tt> value stored in the entity.
+
The following example shows how to use the <tt>@TypeConverter</tt> annotation to convert the <tt>Double</tt> value stored in the database to a <tt>Float</tt> value stored in the entity.
  
 
<span id="Example 19-8"></span>
 
<span id="Example 19-8"></span>
''''' Usage of the @TypeConverter Annotation'''''
+
======'' Example: @TypeConverter Annotation''======
 
<source lang="java">
 
<source lang="java">
 
  @Entity
 
  @Entity

Revision as of 13:49, 29 March 2011


link="http://wiki.eclipse.org/EclipseLink"
EclipseLink
Website
Download
Community
Mailing ListForumsIRC
Bugzilla
Open
Help Wanted
Bug Day
Contribute
Browse Source

Elug api package icon.png Key API TypeConverter

@TypeConverter Annotation

The @TypeConverter is an EclipseLink-specific annotation. You can use it to specify an org.eclipse.persistence.mappings.converters.TypeConversionConverter for modification of the data value(s) during the reading and writing of a mapped attribute.

 
 @Target({TYPE, METHOD, FIELD})
 @Retention(RUNTIME)
 public @interface TypeConverter {
    String name();
    Class dataType() default void.class;
    Class objectType() default void.class;
 }
@TypeConverter Annotation Attributes
Attribute Description Default Required?
name Set this attribute to the String name for your converter. Ensure that this name is unique across the persistence unit. Yes
dataType Set this attribute to the type stored in the database. void.class1 No
objectType Set the value of this attribute to the type stored on the entity. void.class1 No

1 The default is inferred from the type of the persistence field or property.


The following example shows how to use the @TypeConverter annotation to convert the Double value stored in the database to a Float value stored in the entity.

Example: @TypeConverter Annotation
 @Entity
 public class Employee implements Serializable{
     ...
     @TypeConverter (
         name="doubleToFloat",
         dataType=Double.class,
         objectType=Float.class,
     )
     @Convert("doubleToFloat")
     public Number getGradePointAverage() {
         return gradePointAverage;
     }
     ...
 }



Eclipselink-logo.gif
Version: 2.1.0
Other versions...