ConstantTransformer (EclipseLink Core 4.0.2 API)

java.lang.Object
- org.eclipse.persistence.mappings.transformers.FieldTransformerAdapter
- - org.eclipse.persistence.mappings.transformers.ConstantTransformer

All Implemented Interfaces:

Serializable, CoreFieldTransformer<Session>, FieldTransformer
```
public class ConstantTransformer
extends FieldTransformerAdapter
```
Purpose: Allows a field to always be mapped to a constant value. This allows default values to be provided for un-mapped fields.

Since:

10.1.3

Author:

James Sutherland

See Also:

FieldTransformer, Serialized Form

Field Summary

Fields
Modifier and Type Field Description

protected Object value
- Fields inherited from interface org.eclipse.persistence.core.mappings.transformers.CoreFieldTransformer
  BUILD_FIELD_VALUE_METHOD

Constructor Summary

Constructors
Constructor Description

ConstantTransformer()

ConstantTransformer(Object value)
PUBLIC: Return a constant transformer for the constant value.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Object`	`buildFieldValue(Object object, String fieldName, Session session)`	INTERNAL: Always return the constant value.
`Object`	`getValue()`	PUBLIC: Return the value of the constant.
`void`	`setValue(Object value)`	PUBLIC: Set the value of the constant.

Methods inherited from class org.eclipse.persistence.mappings.transformers.FieldTransformerAdapter
initialize

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

- Field Detail
  - value
```
protected Object value
```
- Constructor Detail
  - ConstantTransformer
```
public ConstantTransformer()
```
  - ConstantTransformer
```
public ConstantTransformer(Object value)
```
    PUBLIC: Return a constant transformer for the constant value.
- Method Detail
  - getValue
```
public Object getValue()
```
    PUBLIC: Return the value of the constant.
  - setValue
```
public void setValue(Object value)
```
    PUBLIC: Set the value of the constant.
  - buildFieldValue
```
public Object buildFieldValue(Object object,
                              String fieldName,
                              Session session)
```
    INTERNAL: Always return the constant value.
    
    Specified by:
    
    buildFieldValue in interface CoreFieldTransformer<Session>
    
    Specified by:
    
    buildFieldValue in interface FieldTransformer
    
    Overrides:
    
    buildFieldValue in class FieldTransformerAdapter
    
    Parameters:
    
    object - - an instance of the domain class which contains the attribute
    
    fieldName - - the name of the field being transformed. Used if the user wants to use this transformer for multiple fields.
    
    session - - the current session
    
    Returns:
    
    - The value to be written for the field associated with this transformer