Package org.instancio.internal.generator.util

Class CollectionGenerator<T>

java.lang.Object

org.instancio.internal.generator.AbstractGenerator<Collection<T>>

org.instancio.internal.generator.util.CollectionGenerator<T>

All Implemented Interfaces:

Generator<Collection<T>>, GeneratorSpec<Collection<T>>, CollectionGeneratorSpec<T>, NullableGeneratorSpec<Collection<T>>, SubtypeGeneratorSpec<Collection<T>>

Direct Known Subclasses:

CollectionGeneratorSpecImpl

public class CollectionGenerator<T>
extends AbstractGenerator<Collection<T>>
implements CollectionGeneratorSpec<T>

Field Summary

Fields

Modifier and Type	Field	Description
protected Class<?>	collectionType
protected boolean	isDelegating
protected int	maxSize
protected int	minSize
protected boolean	nullableElements
protected boolean	unique
protected List<Object>	withElements

Constructor Summary

Constructors

Constructor	Description
CollectionGenerator(GeneratorContext context)

Method Summary

Modifier and Type	Method	Description
String	apiMethod()	Returns the public API method name of the generator spec.
Collection<T>	generate(Random random)	Returns a generated value.
Hints	hints()	Hints provided by the generator to the engine.
CollectionGeneratorSpec<T>	maxSize(int size)	Maximum size of collection to generate.
CollectionGeneratorSpec<T>	minSize(int size)	Minimum size of collection to generate.
CollectionGeneratorSpec<T>	nullable()	Indicates that null value can be generated.
CollectionGeneratorSpec<T>	nullable(boolean isNullable)
CollectionGeneratorSpec<T>	nullableElements()	Indicates that null values can be generated for collection elements.
CollectionGeneratorSpec<T>	size(int size)	Size of collection to generate.
CollectionGeneratorSpec<T>	subtype(Class<?> type)	Specifies the type of collection that should be generated.
CollectionGeneratorSpec<T>	unique()	Specifies that a collection containing unique elements should be generated.
final CollectionGeneratorSpec<T>	with(T... elements)	Adds given elements to the generated collection at random positions.

Methods inherited from class org.instancio.internal.generator.AbstractGenerator

getContext, isNullable

Methods inherited from class java.lang.Object

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

Field Details

minSize

protected int minSize

maxSize

protected int maxSize

nullableElements

protected boolean nullableElements

unique

protected boolean unique

withElements

protected List<Object> withElements

collectionType

protected Class<?> collectionType

isDelegating

protected boolean isDelegating

Constructor Details

CollectionGenerator

public CollectionGenerator(GeneratorContext context)

Method Details

apiMethod

public String apiMethod()

Description copied from class: AbstractGenerator

Returns the public API method name of the generator spec. The returned name is used for reporting validation errors.

Specified by:

apiMethod in class AbstractGenerator<Collection<T>>

Returns:

spec name if defined, or null otherwise

size

public CollectionGeneratorSpec<T> size(int size)

Description copied from interface: CollectionGeneratorSpec

Size of collection to generate.

Specified by:

size in interface CollectionGeneratorSpec<T>

Parameters:

size - of collection

Returns:

spec builder

minSize

public CollectionGeneratorSpec<T> minSize(int size)

Description copied from interface: CollectionGeneratorSpec

Minimum size of collection to generate.

Specified by:

minSize in interface CollectionGeneratorSpec<T>

Parameters:

size - minimum size (inclusive)

Returns:

spec builder

maxSize

public CollectionGeneratorSpec<T> maxSize(int size)

Description copied from interface: CollectionGeneratorSpec

Maximum size of collection to generate.

Specified by:

maxSize in interface CollectionGeneratorSpec<T>

Parameters:

size - maximum size (inclusive)

Returns:

spec builder

nullable

public CollectionGeneratorSpec<T> nullable()

Description copied from interface: NullableGeneratorSpec

Indicates that null value can be generated.

Specified by:

nullable in interface CollectionGeneratorSpec<T>

Specified by:

nullable in interface NullableGeneratorSpec<T>

Overrides:

nullable in class AbstractGenerator<Collection<T>>

Returns:

spec builder

nullable

public CollectionGeneratorSpec<T> nullable(boolean isNullable)

Overrides:

nullable in class AbstractGenerator<Collection<T>>

nullableElements

public CollectionGeneratorSpec<T> nullableElements()

Description copied from interface: CollectionGeneratorSpec

Indicates that null values can be generated for collection elements.

Specified by:

nullableElements in interface CollectionGeneratorSpec<T>

Returns:

spec builder

subtype

public CollectionGeneratorSpec<T> subtype(Class<?> type)

Description copied from interface: CollectionGeneratorSpec

Specifies the type of collection that should be generated.

Specified by:

subtype in interface CollectionGeneratorSpec<T>

Specified by:

subtype in interface SubtypeGeneratorSpec<T>

Parameters:

type - of collection to generate

Returns:

spec builder

unique

public CollectionGeneratorSpec<T> unique()

Description copied from interface: CollectionGeneratorSpec

Specifies that a collection containing unique elements should be generated.

Special care must be taken when using this method and CollectionGeneratorSpec.size(int). Consider the following example where the favourite numbers field is of type Set<Integer>:

   Person person = Instancio.of(Person.class)
       .generate(allInts(), gen -> gen.ints().range(1, 5))
       .generate(field(Person::getFavouriteNumbers), gen -> gen.collection().unique().size(10))
       .create();
 

Since the integer range is restricted to 1..5, it is impossible to generate a collection of 10 unique elements. In this case, a collection of size 5 will be generated.

Specified by:

unique in interface CollectionGeneratorSpec<T>

Returns:

spec builder

with

@SafeVarargs
public final CollectionGeneratorSpec<T> with(T... elements)

Description copied from interface: CollectionGeneratorSpec

Adds given elements to the generated collection at random positions. Note that the elements are added after the collection has been generated.

Example:

  // will generate a collection of size 5
  generate(field("someList"), gen -> gen.collection().size(3).with("element1", "element2")
 

Specified by:

with in interface CollectionGeneratorSpec<T>

Parameters:

elements - to add

Returns:

spec builder

generate

public Collection<T> generate(Random random)

Description copied from interface: Generator

Returns a generated value.

If this method produces random data, the data needs to be generated using the provided Random instance. This ensures generated values are reproducible for a given seed value.

Specified by:

generate in interface Generator<T>

Parameters:

random - provider for generating random values

Returns:

generated value or null if value is nullable, could not be generated, or generation is delegated to the engine

hints

public Hints hints()

Description copied from interface: Generator

Hints provided by the generator to the engine.

The most important hint for custom generators is AfterGenerate. This hint indicates whether the object created by this generator:

• should be populated (for example, if it has null fields)
• can be modified using selectors

For example, setting the hint to AfterGenerate.POPULATE_NULLS will cause Instancio to populate null fields on the object returned by this generator:

   @Override
   public Hints hints() {
       return Hints.afterGenerate(AfterGenerate.POPULATE_NULLS);
   }
 

If the action is not specified, default behaviour will be based on the AfterGenerate value configured in the Settings using the key Keys.AFTER_GENERATE_HINT.

In addition, the following hints can be provided for populating data structures:

• ArrayHint
• CollectionHint
• MapHint

Specified by:

hints in interface Generator<T>

Overrides:

hints in class AbstractGenerator<Collection<T>>

Returns:

hints from this generator to the engine

See Also:

• Hint
• Hints
• AfterGenerate