org.apache.geode.pdx

## Interface WritablePdxInstance

- All Superinterfaces:
    PdxInstance, java.io.Serializable

      public interface WritablePdxInstance
      extends PdxInstance

  WritablePdxInstance is a `PdxInstance` that also supports field modification using the `setField` method. To get a WritablePdxInstance call `createWriter`.
  Since:
    GemFire 6.6

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `setField(java.lang.String fieldName, java.lang.Object value)` Set the existing named field to the given value.

    - ### Methods inherited from interface org.apache.geode.pdx.PdxInstance

      `createWriter, equals, getClassName, getField, getFieldNames, getObject, hasField, hashCode, isEnum, isIdentityField, toString`

- - ### Method Detail

    - #### setField

          void setField(java.lang.String fieldName,
                        java.lang.Object value)

      Set the existing named field to the given value. The setField method has copy-on-write semantics. So for the modifications to be stored in the cache the WritablePdxInstance must be put into a region after setField has been called one or more times.
      Parameters:
        `fieldName` - name of the field whose value will be set
        `value` - value that will be assigned to the field
      Throws:
        `PdxFieldDoesNotExistException` - if the named field does not exist
        `PdxFieldTypeMismatchException` - if the type of the value is not compatible with the field