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PropertyService

PropertyService#

About#

The PropertyService gets and sets the values for your application’s properties in a typesafe manner. These might be stored in *.properties files (being “immutable” properties) or in database (“mutable” properties).

Architecture#

Properties are referenced to using their id, which may have one of two types:

  • ImmutablePropertyId for immutable properties that are linked to configuration.properties.

  • MutablePropertyId for mutable properties that are stored in database in table Parameter as String. Beware that the other columns of this table are deprecated.

Here are the basic principles:

  • Properties are first registered using their ID during the application initialization. The registration involves telling to the PropertyService how to convert the property value to and from its string representation, which is done by providing a Converter (a Guava type), or (for immutable properties that don’t need to be converter back to string) a Function.

  • During the execution of the application, the property values may be retrived using the service’s get method, or altered using the set method.

Using it in your application#

Declare the IDs#

You must first declare constants for your property ids. You’d better have two sets of property ids: one for you core (non-UI) project and the other for you webapp (UI) project.

The keys passed as parameters to AbstractPropertyIds’s methods are the one used to retrieve the values, either in the configuration.properties file or in database.

public final class YourAppCorePropertyIds extends AbstractPropertyIds {

	public static final ImmutablePropertyId<Integer> CORE_IMMUTABLE_INTEGER_PROPERTY = immutable("core.immutable.integer.property");
	public static final ImmutablePropertyId<MyType> CORE_IMMUTABLE_MYTYPE_PROPERTY = immutable("core.immutable.mytype.property");

	public static final MutablePropertyId<String> CORE_MUTABLE_STRING_PROPERTY = mutable("core.mutable.string.property");

}

public final class YourAppWebappPropertyIds {

	public static final ImmutablePropertyId<Long> WEBAPP_IMMUTABLE_LONG_PROPERTY = immutable("webapp.immutable.long.property");
	public static final ImmutablePropertyId<MyType> WEBAPP_IMMUTABLE_MYTYPE_PROPERTY = immutable("webapp.immutable.mytype.property");

	public static final MutablePropertyId<String> WEBAPP_MUTABLE_STRING_PROPERTY = mutable("webapp.mutable.string.property");

}

Register the properties#

In your core module set up a JavaConfig as follows.

Beware that AbstractApplicationPropertyConfig also declares the property service, which is a singleton. Thus it must only be used once (in your core module).

@Configuration
public class YourAppCoreApplicationPropertyConfig extends AbstractApplicationPropertyConfig {

	@Override
	public IMutablePropertyDao mutablePropertyDao() {
		return new ParameterDaoImpl();
	}

	@Override
	public void register(IPropertyRegistry registry) {
		// register core properties here
	}

}

In your webapp module set up a JavaConfig as follows:

@Configuration
public class YourAppWebappApplicationPropertyRegisterConfig extends AbstractApplicationPropertyRegistryConfig {

	@Override
	public void register(IPropertyRegistry registry) {
		// register webapp properties here
	}

}

IPropertyRegistry provides a bunch of methods to register properties. See details below.

Access the properties#

Anywhere an IPropertyService is available (it can be injected), do the following:

@Autowired
private IPropertyService propertyService;

// Get a value
propertyService.get(YourAppCorePropertyIds.CORE_IMMUTABLE_MYTYPE_PROPERTY);

// Set a value (only for mutable properties)
propertyService.set(YourAppCorePropertyIds.CORE_MUTABLE_STRING_PROPERTY, "NewValue");

Details about registration#

Important note#

It is strongly recommended to define a default value for collection properties in order to always get a collection even if the value is null.

Examples#

Basic immutable property

public static final ImmutablePropertyId<String> MAINTENANCE_URL = immutable("maintenance.url");

propertyService.registerString(MAINTENANCE_URL);

Immutable property with custom converter/function

public static final ImmutablePropertyId<Date> DATE_PICKER_RANGE_MAX_DATE = immutable("datePicker.range.max.yearsFromNow");

propertyService.registerImmutable(DATE_PICKER_RANGE_MAX_DATE, new Function<String, Date>() {
	@Override
	public Date apply(String input) {
		Integer years = Ints.stringConverter().convert(input);
		if (years == null) {
			return null;
		}
		return DateUtils.truncate(
				DateUtils.addYears(new Date(), years),
				Calendar.DAY_OF_MONTH
		);
	}
});

Mutable property with dynamic key with default value

public static final MutablePropertyIdTemplate<Boolean> DATA_UPGRADE_DONE_TEMPLATE = mutableTemplate("dataUpgrade.%1s");
public static final MutablePropertyId<Boolean> dataUpgrade(IDataUpgrade dataUpgrade) {
	return DATA_UPGRADE_DONE_TEMPLATE.create(dataUpgrade.getName());
}

propertyService.registerBoolean(DATA_UPGRADE_DONE_TEMPLATE, false);

Property - enum

public static final ImmutablePropertyId<Environment> ENVIRONMENT = immutable("environment");

propertyService.registerEnum(ENVIRONMENT, Environment.class, Environment.production);

Property - collection

public static final ImmutablePropertyId<List<MediaType>> FICHIER_PIECE_JOINTE_MEDIA_TYPES = immutable("fichier.pieceJointe.mediaTypes");

propertyService.register(FICHIER_PIECE_JOINTE_MEDIA_TYPES, new StringCollectionConverter<>(Enums.stringConverter(MediaType.class), Suppliers2.<MediaType>arrayList()));
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