com.chemaxon.apidiscovery

Class Discovery

java.lang.Object

com.chemaxon.apidiscovery.Discovery

@Beta
 @PublicAPI
public final class Discovery
extends Object

Utility methods for parameter discovery.

Please note that this class is marked with Beta annotation, so it can be subject of incompatible changes or removal in later releases.

Method Summary

Modifier and Type	Method and Description
static <T extends Annotation> T	getAnnotation(Class<T> a, Object o) Retrieve an annotation on an object.
static <T extends Annotation> T	getAnnotationForClass(Class<T> annotationClass, Class<?> clazz) Retrieve annotation for a class.
static <T extends Annotation> Optional<T>	getAnnotationIfPresent(Class<T> a, Object o) Retrieve an annotation on an object if present.
static Description	getDescriptionAnnotation(Object o) Retrieve the description annotation on an object.
static <T> Optional<ParameterBuilder<T>>	initializeBuilderIfExists(T o) Create initial Builder if possible.
static boolean	isParametrized(Object o) Check if an object is parametrized.
static <T> List<CreatorWrapper<T>>	listCreators(Object o, Class<T> targetType) CreatorWrapper acts as a type-dependent service loader.
static <T> List<InstanceWrapper<T>>	listInstances(Class<T> type) Collect instances of a specific type.
static List<ParameterWrapper>	listParameters(Object o) Retrieve parameters for a mutable parameter object.
static <T> Optional<InstanceWrapper<T>>	selectInstance(Class<T> type, String shortName) Look up an instance by its short name.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

listInstances

@Beta
public static <T> List<InstanceWrapper<T>> listInstances(Class<T> type)

Collect instances of a specific type.

Type Parameters:

T - Type to collect

Parameters:

type - Type to collect

Returns:

One or more instances of the specified type. Interfaces are retrieved as services; classes are instantiated with their nullary constructors; enums are enumerated

selectInstance

public static <T> Optional<InstanceWrapper<T>> selectInstance(Class<T> type,
                                                              String shortName)

Look up an instance by its short name.

Type Parameters:

T - Type to collect

Parameters:

type - Type to collect (by listInstances(java.lang.Class)

shortName - Short name of the instance to select

Returns:

The first matching instance if found

isParametrized

@Beta
public static boolean isParametrized(Object o)

Check if an object is parametrized.

Parameters:

o - Object in question

Returns:

true if o is parametrized

listParameters

@Beta
public static List<ParameterWrapper> listParameters(Object o)

Retrieve parameters for a mutable parameter object. Parameter set mode is specified by Parametrized.parameterSetMode() on the objects Parametrized annotation.

Parameters:

o - Mutable parametrized object annotated with Parametrized

Returns:

Parameters of o wrapped

Throws:

IllegalArgumentException - when o is not annotated with Parametrized or no parameters found

getAnnotationForClass

@Beta
public static <T extends Annotation> T getAnnotationForClass(Class<T> annotationClass,
                                                                   Class<?> clazz)

Retrieve annotation for a class. Note that enum constants are not handled by this method.

Type Parameters:

T - Annotation class

Parameters:

annotationClass - Annotation class

clazz - Target class

Returns:

Annotation retrieved

Throws:

IllegalArgumentException - when no Description annotation found

getAnnotationIfPresent

@Beta
public static <T extends Annotation> Optional<T> getAnnotationIfPresent(Class<T> a,
                                                                              Object o)

Retrieve an annotation on an object if present.

Type Parameters:

T - Annotation class

Parameters:

a - Annotation class

o - Object to examine

Returns:

The description annotation if exist

getAnnotation

@Beta
public static <T extends Annotation> T getAnnotation(Class<T> a,
                                                           Object o)

Retrieve an annotation on an object.

Type Parameters:

T - Annotation class

Parameters:

a - Annotation class

o - Object to examine

Returns:

The annotation if exists or null; If o is an instance of an enum then enum constant annotation is retrieved

Throws:

IllegalArgumentException - when no annotation found

getDescriptionAnnotation

@Beta
public static Description getDescriptionAnnotation(Object o)

Retrieve the description annotation on an object.

Parameters:

o - Object to examine

Returns:

The description annotation if exists or null; If o is an instance of an enum then enum constant annotation is retrieved

Throws:

IllegalArgumentException - when no Description annotation found

listCreators

@Beta
public static <T> List<CreatorWrapper<T>> listCreators(Object o,
                                                             Class<T> targetType)

CreatorWrapper acts as a type-dependent service loader.

Note that the order of the returned list is defined by

Type Parameters:

T - type to be created

Parameters:

targetType - type to be created

o - Instance on which the creators should be called

Returns:

All distinct creator parameters

initializeBuilderIfExists

@Beta
public static <T> Optional<ParameterBuilder<T>> initializeBuilderIfExists(T o)

Create initial Builder if possible.

Builder association is identified by annotation BuilderClass

Type Parameters:

T - Parameter object type

Parameters:

o - An object

Returns:

An associated builder instance if the parameter object has associated builder.