15.1 Data Conversions

Built-in Conversions

• Number with format
• Enum
• Date/Timestamp
• TemporalAccessor: e.g., LocalDate, LocalDateTime
• Locale
• ReportPeriod: e.g. 2022-M2, 2022-Q2, 2022-12-15
• Persistence Entity
• Default conversion with Constructor

Number with Format

    @Property(name="expense",
        renderStyle=@RenderStyleDef(number=@NumberDesc(type=NumberDescriptor.Type.CURRENCY)))       

    @Property(name="quantity",
        renderStyle=@RenderStyleDef(number=@NumberDesc(type=NumberDescriptor.Type.NUMBER,
            minFractionDigits=0, maxFractionDigits=0)))       
 
    @Property(name="rate",
        renderStyle=@RenderStyleDef(number=@NumberDesc(type=NumberDescriptor.Type.PERCENT,
            minFractionDigits=0, maxFractionDigits=3)))

Enum

public enum Color {
	RED,
	GREEN,
	BLUE
}

Date/Timestamp

Timestamp is converted to/from string using the time zone specified in the Parameters of the DataAccessUnit.

TemporalAccessor

Locale

ReportPeriod

Persistence Entity

• NormativeId: nid/text
• Hierarchy: hierarchyId/text
• User: username/text
• Others: id/text

Other Types

Primitive types:

	new Integer(text);

	public class Color {
		private String name;
		
		public Color(String name) {
			this.name = name;
		}
	}

Collection

Example 1: collection of enum values

public enum Color {
	RED,
	GREEN,
	BLUE
}

Example 2: collection of persistence entities

@Entity(name="Employee")
public class Employee extends PersistenceEntityBase implements NormativeId {

}

With autoComplete enabled, a list of suggestions will be shown while user is typing. Or open input dialog, user can create new entities or select existing entities.

Select Items

	@Override
	public List<SelectItem> getPropertySelectItems(EntityProperty<T> property) throws SystemException {
		// The values of select items must be String
	}
  
	@Override
	public List<SelectItem> getDynamicSelectItems(PersistenceDataBackingBean<T> backingBean, 
  		T entity, EntityProperty<T> property) throws SystemException {
		// The values of select items must be String
	}

	SelectItemListProvider.addEmptySelection(selectItems, "Select one", true);

Class SelectItemListProvider provides built-in select items such as for currency, locale and time zone. SelectItem labels are of I18NName type, which will be translated from resource bundles during render phase.

Custom Converter

	@Property(name="serialNumber", view={ViewType.ENTITY},
		converter=SerialNumberConverter.class)

public class SerialNumberConverter<T extends PersistenceEntity> implements ValueConverter<T>, Serializable {

	@Override
	public Object getValueAsObject(EntityProperty<T> ep, String value) throws SystemException {
		if (value == null)
			return null;
		
		// remove separator -
		return value.replaceAll("-", "");
	}

	@Override
	public String getValueAsString(EntityProperty<T> ep, T entity) throws SystemException {
		// split into groups of 4 chars
		String value = (String)ep.getValue(entity);
		if (value == null)
			return null;
		
		int len = value.length();
		StringBuilder sb = new StringBuilder();
		for (int i=0; i<len; i++) {
			if (i>0 && i % 4 == 0)
				sb.append('-');
			sb.append(value.charAt(i));
		}
		
		return sb.toString();
	}
}

Extends EntityProperty

public MyEntityProperty<T extends PersistenceEntity> extends EntityProperty<T> {
	@Override
	protected Object convert(Object value) throws InvalidValueException, SystemException {
		...
	}

	// convert to string
	@Override
	protected Object getValueInternal(T entity, boolean convertToString) throws SystemException {
		...
	}
}

see Extensions on how to create custom EntityProperty types and render styles for custom UI components.