com.holonplatform.vaadin.flow.navigator.annotations

Annotation Type QueryParameter

@Retention(value=RUNTIME)
 @Target(value=FIELD)
 @Documented
 @Inherited
public @interface QueryParameter

Annotation which can be used on a navigation target class field to inject the URL query parameter value which corresponds to the parameter name declared using the annotation value().

The the parameter name (i.e. the annotation value()) is blank or empty, the annotated field name will be used as parameter name.

This annotation supports a required() attribute to require a parameter value and the defaultValue() attribute to provide a default parameter value when the value is not available from the navigation URL.

The default supported parameter value types are:

• String.
• Number. The . (dot) character must be used as decimal separator for decimal numbers.
• Boolean. The true and false String values are admitted as parameter values.
• Enum. The enumeration value name must be used as parameter value.
• Date. The ISO-8601 standard format must be used as parameter value representation.
• LocalDate. The ISO-8601 standard format must be used as parameter value representation.
• LocalTime. The ISO-8601 standard format must be used as parameter value representation.
• LocalDateTime. The ISO-8601 standard format must be used as parameter value representation.

The Set and List collection types are also supported as parameter value type, in order to obtain multiple parameter values.

At last, the Optional type is supported as parameter value type.

One or more NavigationParameterTypeMapper can be registered using the Java ServiceLoader extensions to provide support to further parameter value types.

Since:

5.2.0

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
String	defaultValue Get the default parameter value if no value is provided.
boolean	required Declares this parameter as required.
String	value The name of the URL query parameter which value has to be injected into the annotated navigation target class field.

Element Detail

value

public abstract String value

The name of the URL query parameter which value has to be injected into the annotated navigation target class field.

If the parameter name is blank or empty, the annotated field name will be used as parameter name.

Returns:

the parameter name, or empty to use the annotated field name

Default:

""

required

public abstract boolean required

Declares this parameter as required. If the parameter value is not available and no defaultValue() is defined, an error will be thrown.

Default is false.

Returns:

true if parameter is required, false (default) otherwise

Default:

false

defaultValue

public abstract String defaultValue

Get the default parameter value if no value is provided.

According to the parameter value type, a suitable String representation must be provided for the default value:

• For numeric values, the . (dot) character must be used as decimal separator.
• For boolean values, only the words true and false are admitted.
• For Enum type values, the enumeration name must be used as parameter value.
• For temporal (date and time) type values, the ISO-8601 standard format must be used for the parameter value.

Returns:

the default parameter value, or an empty String for none

Default:

""