org.junit.jupiter.api.extension

Interface ParameterResolver

All Superinterfaces:

Extension

@API(status=STABLE,
     since="5.0")
public interface ParameterResolver
extends Extension

ParameterResolver defines the API for Extensions that wish to dynamically resolve arguments for parameters at runtime.

If a constructor for a test class or a @Test, @BeforeEach, @AfterEach, @BeforeAll, or @AfterAll method declares a parameter, an argument for the parameter must be resolved at runtime by a ParameterResolver.

Implementations must provide a no-args constructor.

Since:

5.0

See Also:

supportsParameter(ParameterContext, ExtensionContext), resolveParameter(ParameterContext, ExtensionContext), ParameterContext

Method Summary

Modifier and Type	Method and Description
Object	resolveParameter(ParameterContext parameterContext, ExtensionContext extensionContext) Resolve an argument for the Parameter in the supplied ParameterContext for the supplied ExtensionContext.
boolean	supportsParameter(ParameterContext parameterContext, ExtensionContext extensionContext) Determine if this resolver supports resolution of an argument for the Parameter in the supplied ParameterContext for the supplied ExtensionContext.

Method Detail

supportsParameter

boolean supportsParameter(ParameterContext parameterContext,
                          ExtensionContext extensionContext)
                   throws ParameterResolutionException

Determine if this resolver supports resolution of an argument for the Parameter in the supplied ParameterContext for the supplied ExtensionContext.

The Method or Constructor in which the parameter is declared can be retrieved via ParameterContext.getDeclaringExecutable().

Parameters:

parameterContext - the context for the parameter for which an argument should be resolved; never null

extensionContext - the extension context for the Executable about to be invoked; never null

Returns:

true if this resolver can resolve an argument for the parameter

Throws:

ParameterResolutionException

See Also:

resolveParameter(org.junit.jupiter.api.extension.ParameterContext, org.junit.jupiter.api.extension.ExtensionContext), ParameterContext

resolveParameter

Object resolveParameter(ParameterContext parameterContext,
                        ExtensionContext extensionContext)
                 throws ParameterResolutionException

Resolve an argument for the Parameter in the supplied ParameterContext for the supplied ExtensionContext.

This method is only called by the framework if supportsParameter(org.junit.jupiter.api.extension.ParameterContext, org.junit.jupiter.api.extension.ExtensionContext) previously returned true for the same ParameterContext and ExtensionContext.

The Method or Constructor in which the parameter is declared can be retrieved via ParameterContext.getDeclaringExecutable().

Parameters:

parameterContext - the context for the parameter for which an argument should be resolved; never null

extensionContext - the extension context for the Executable about to be invoked; never null

Returns:

the resolved argument for the parameter; may only be null if the parameter type is not a primitive

Throws:

ParameterResolutionException

See Also:

supportsParameter(org.junit.jupiter.api.extension.ParameterContext, org.junit.jupiter.api.extension.ExtensionContext), ParameterContext