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Difference between revisions of "EclipseLink/UserGuide/JPA/Basic JPA Development/Mapping/Basic Mappings/Default Conversions and Converters/TypeConverter"
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− | + | {{EclipseLink_AttributeTable | |
− | + | |captioni=<span id="Table 19-8">@TypeConverter Attributes</span> | |
− | <span id="Table 19-8"></span> | + | |content= |
− | + | <tr> | |
− | + | <td>'''<tt>name</tt>'''</td> | |
− | + | <td>Set this attribute to the <tt>String</tt> name for your converter. Ensure that this name is unique across the persistence unit.</td> | |
− | + | <td></td> | |
− | + | <td>Yes</td> | |
− | + | </tr> | |
− | + | <tr> | |
− | + | <td>'''<tt>dataType</tt>'''</td> | |
− | <tt>name</tt> | + | <td>Set this attribute to the type stored in the database.</td> |
− | + | <td><tt>void.class</tt><sup>1</sup></td> | |
− | Set this attribute to the <tt>String</tt> name for your converter. Ensure that this name is unique across the persistence unit. | + | <td>No</td> |
− | + | </tr> | |
− | + | <tr> | |
− | + | <td>'''<tt>objectType</tt>'''</td> | |
− | + | <td>Set the value of this attribute to the type stored on the entity.</td> | |
− | + | <td><tt>void.class</tt><sup>1</sup></td> | |
− | + | <td>No</td> | |
− | <tt>dataType</tt> | + | </tr> |
− | + | }} | |
− | Set this attribute to the type stored in the database. | + | <sup>1</sup> The default is inferred from the type of the persistence field or property. |
− | + | ||
− | <tt>void.class</tt><sup>1</sup> | + | |
− | + | ||
− | + | ||
− | + | ||
− | + | ||
− | <tt>objectType</tt> | + | |
− | + | ||
− | Set the value of this attribute to the type stored on the entity. | + | |
− | + | ||
− | <tt>void.class</tt><sup>1</sup> | + | |
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Revision as of 14:20, 17 June 2010
Key API {{{apis}}}
@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; }
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.
This 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.
Usage of the @TypeConverter Annotation
@Entity public class Employee implements Serializable{ ... @TypeConverter ( name="doubleToFloat", dataType=Double.class, objectType=Float.class, ) @Convert("doubleToFloat") public Number getGradePointAverage() { return gradePointAverage; } ... }