ch.jalu.configme.properties

Interface Property<T>

Type Parameters:

T - the property type

All Known Implementing Classes:

BaseProperty, BeanProperty, BooleanProperty, DoubleProperty, EnumProperty, IntegerProperty, LowercaseStringSetProperty, OptionalProperty, StringListProperty, StringProperty

public interface Property<T>

Property interface. A property knows its path, its type, and can convert the values from a property reader to a value of its type (if the values of the reader are valid). Properties define their path and their behavior but do not keep track of their value.

Property implementations should always extend from BaseProperty instead of implementing this interface directly.

Method Summary

Modifier and Type	Method and Description
T	determineValue(PropertyReader propertyReader) Returns the value, based on the given reader, which should be used for this property.
T	getDefaultValue() Returns the default value of this property.
String	getPath()
boolean	isPresent(PropertyReader propertyReader) Returns true if a valid value for this property is present in the property reader, i.e.
boolean	isValidValue(T value) Returns whether the value can be associated to the given property, i.e.
Object	toExportValue(T value) Converts the given value to a representation that is suitable for exporting by a property resource.

Method Detail

getPath

String getPath()

Returns:

the path of the property

determineValue

T determineValue(PropertyReader propertyReader)

Returns the value, based on the given reader, which should be used for this property. By default this is the value as constructed from the reader, and otherwise the default value. Implementations of BaseProperty never return null. The return value must be in sync with isValidValue(Object).

Parameters:

propertyReader - the reader to construct the value from (if possible)

Returns:

the value to associate to this property

getDefaultValue

T getDefaultValue()

Returns the default value of this property.

Returns:

the default value

isPresent

boolean isPresent(PropertyReader propertyReader)

Returns true if a valid value for this property is present in the property reader, i.e. true if and only if there is a value at the property's path in the reader and it can be used to construct a value for the property.

Parameters:

propertyReader - the reader to use

Returns:

true if a valid value is present in the reader, false otherwise

isValidValue

boolean isValidValue(T value)

Returns whether the value can be associated to the given property, i.e. whether it fulfills all requirements which may be imposed by the property type.

This method is used in ConfigurationDataImpl.setValue(ch.jalu.configme.properties.Property<T>, T), which throws an exception if this method returns false. Therefore, this method is intended as a last catch for invalid values and to ensure that programmatically no invalid value can be set. Extended validation of values encountered in the property reader should be preferably handled determineValue(ch.jalu.configme.resource.PropertyReader) or in a MigrationService.

Parameters:

value - the value to check

Returns:

true if the value can be used for the property, false otherwise

toExportValue

@Nullable
Object toExportValue(T value)

Converts the given value to a representation that is suitable for exporting by a property resource. The return value should contain the data in the given value represented with only basic types (String, Number, Boolean), as well as lists and maps thereof.

The values which are suitable for returning depend on the support of the used property resource. By default, the supported types include null, String, Integer, Double, Boolean; Collection of the aforementioned types; Map with String keys and values of any of the aforementioned types. Maps and collections can be nested at any arbitrary level. Null signifies that the property/value should be skipped in the export.

Parameters:

value - the value to convert to an export value

Returns:

value to use for export, null to skip the property