org.sormula.translator.standard

Class EnumTranslator<T extends java.lang.Enum<T>>

java.lang.Object

org.sormula.translator.standard.EnumTranslator<T>

All Implemented Interfaces:

TypeTranslator<java.lang.Enum<T>>

Direct Known Subclasses:

EnumToStringTranslator

public class EnumTranslator<T extends java.lang.Enum<T>>
extends java.lang.Object
implements TypeTranslator<java.lang.Enum<T>>

TypeTranslator to use for Enum fields. Writes Enum name (Enum.name()) to column as a String. Reads column as a String Enum name (Enum.name()) and converts name to Enum with Enum.valueOf(Class, String).

Column should be a sql type that is compatible with java String (like varchar) and wide enough for the longest Enum name.

This class and subclasses may be used as a TypeTranslator for Enum fields in one of two ways:

• by specifying with ImplicitType.translator() or ExplicitType.translator().
• by specifying in EnumType.translator().

This class is the default translator to use for Enum types when no annotation is specified for an Enum field within a row class.

Create a subclass for a custom TypeTranslator for Enum fields. Override read(ResultSet, int) and write(PreparedStatement, int, Enum) if column is some type other than a String. Override enumToColumn(Enum) and columnToEnum(Object) to store something other than Enum name in database.

Since:

3.3

Author:

Jeff Miller

Constructor Summary

Constructors

Constructor and Description
EnumTranslator()

Method Summary

Modifier and Type	Method and Description
protected java.lang.Enum<T>	columnToEnum(java.lang.Object columnValue) Converts a table column value to an Enum with Enum.valueOf(Class, String).
protected java.lang.Object	enumToColumn(java.lang.Enum<T> enumValue) Converts an Enum constant to a value that will be stored in the table column.
T	getDefaultEnum() Gets the default Enum associated with getDefaultEnumName().
java.lang.String	getDefaultEnumName() Gets the name of the Enum to use in read(ResultSet, int) when the value read from database cannot be found in Class.getEnumConstants() of class getEnumClass().
java.lang.Class<T>	getEnumClass() Gets the class of Enum that is translated.
java.lang.Enum<T>	read(java.sql.ResultSet resultSet, int columnIndex) Reads the column as a String and returns columnToEnum(Object).
void	setDefaultEnumName(java.lang.String defaultEnumName) Sets the name of the Enum to use in read(ResultSet, int) when the value read from the database is not a valid Enum.
void	setEnumClass(java.lang.Class<T> enumClass) Sets the class of Enum to translate.
void	write(java.sql.PreparedStatement preparedStatement, int parameterIndex, java.lang.Enum<T> parameter) Writes the return of enumToColumn(Enum) for Enum parameter to database as a String.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

EnumTranslator

public EnumTranslator()

Method Detail

getEnumClass

public java.lang.Class<T> getEnumClass()

Gets the class of Enum that is translated.

Returns:

Class of Enum to be translated

setEnumClass

public void setEnumClass(java.lang.Class<T> enumClass)

Sets the class of Enum to translate. This method is typically invoked by RowTranslator to initialize this translator when Table object is initialized that contains an Enum field.

Parameters:

enumClass - Class of Enum to be translated

getDefaultEnumName

public java.lang.String getDefaultEnumName()

Gets the name of the Enum to use in read(ResultSet, int) when the value read from database cannot be found in Class.getEnumConstants() of class getEnumClass().

Returns:

default name of Enum to use; empty string for no default (null Enum)

setDefaultEnumName

public void setDefaultEnumName(java.lang.String defaultEnumName)

Sets the name of the Enum to use in read(ResultSet, int) when the value read from the database is not a valid Enum. If no default has been set then read(ResultSet, int) will return null.

setEnumClass(Class) must be invoked prior to invoking this method. This method is invoked by RowTranslator when Table object is initialized.

Parameters:

defaultEnumName - default name of Enum to use or empty string for no default

getDefaultEnum

public T getDefaultEnum()

Gets the default Enum associated with getDefaultEnumName().

Returns:

default Enum; null if no default

write

public void write(java.sql.PreparedStatement preparedStatement,
                  int parameterIndex,
                  java.lang.Enum<T> parameter)
           throws java.lang.Exception

Writes the return of enumToColumn(Enum) for Enum parameter to database as a String. By default enumToColumn(Enum) returns Enum.name(). Override this method if a type other than String is to be written.

See enumToColumn(Enum) for details about what will be written. Sets parameter value in the prepared statement.

Specified by:

write in interface TypeTranslator<java.lang.Enum<T extends java.lang.Enum<T>>>

Parameters:

preparedStatement - set column value as parameter in this statement

parameterIndex - set parameter at this index

parameter - value to set in prepared statement

Throws:

java.lang.Exception - if error

read

public java.lang.Enum<T> read(java.sql.ResultSet resultSet,
                              int columnIndex)
                       throws java.lang.Exception

Reads the column as a String and returns columnToEnum(Object). If column is null then null is returned. If no Enum can be found, then the getDefaultEnum() is returned.

See columnToEnum(Object) for details about what will be returned. Reads value from result set.

Specified by:

read in interface TypeTranslator<java.lang.Enum<T extends java.lang.Enum<T>>>

Parameters:

resultSet - read value from this result set

columnIndex - read value at this column index from result set

Returns:

result set value at parameter index

Throws:

java.lang.Exception - if error

enumToColumn

protected java.lang.Object enumToColumn(java.lang.Enum<T> enumValue)

Converts an Enum constant to a value that will be stored in the table column. This method returns Enum.name(). Override this method to use a custom value.

Parameters:

enumValue - the Enum constant to convert

Returns:

Enum.name(); null if enumValue is null

Since:

4.1

columnToEnum

protected java.lang.Enum<T> columnToEnum(java.lang.Object columnValue)

Converts a table column value to an Enum with Enum.valueOf(Class, String). Override this method if you returned a custom value for enumToColumn(Enum).

Parameters:

columnValue - value read from table column that stores Enum

Returns:

Enum where enumToColumn(Enum) equals columnValue; null if columnValue is null; getDefaultEnum() if columnValue cannot be found using Enum.valueOf(Class, String).

Since:

4.1