org.apache.tinkerpop.gremlin.structure

Interface Property<V>

All Known Subinterfaces:

VertexProperty<V>

All Known Implementing Classes:

DetachedProperty, DetachedVertexProperty, EmptyProperty, EmptyVertexProperty, HadoopProperty, HadoopVertexProperty, ReferenceProperty, ReferenceVertexProperty, StarGraph.StarProperty, StarGraph.StarVertexProperty, TinkerProperty, TinkerVertexProperty

public interface Property<V>

A Property denotes a key/value pair associated with an Edge. A property is much like a Java8 Optional in that a property can be not present (i.e. empty). The key of a property is always a String and the value of a property is an arbitrary Java object. Each underlying graph engine will typically have constraints on what Java objects are allowed to be used as values.

Author:

Marko A. Rodriguez (http://markorodriguez.com), Stephen Mallette (http://stephen.genoprime.com)

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Property.Exceptions Common exceptions to use with a property.

Method Summary

Modifier and Type	Method and Description
Element	element() Get the element that this property is associated with.
static <V> Property<V>	empty() Create an empty property that is not present.
default void	ifPresent(Consumer<? super V> consumer) If the property is present, the consume the value as specified by the Consumer.
boolean	isPresent() Whether the property is empty or not.
String	key() The key of the property.
default V	orElse(V otherValue) If the value is present, return the value, else return the provided value.
default V	orElseGet(Supplier<? extends V> valueSupplier) If the value is present, return the value, else generate a value given the Supplier.
default <E extends Throwable> V	orElseThrow(Supplier<? extends E> exceptionSupplier) If the value is present, return the value, else throw the exception generated by the Supplier.
void	remove() Remove the property from the associated element.
V	value() The value of the property.

Method Detail

key

String key()

The key of the property.

Returns:

The property key

value

V value()
 throws NoSuchElementException

The value of the property.

Returns:

The property value

Throws:

NoSuchElementException - thrown if the property is empty

isPresent

boolean isPresent()

Whether the property is empty or not.

Returns:

True if the property exists, else false

ifPresent

default void ifPresent(Consumer<? super V> consumer)

If the property is present, the consume the value as specified by the Consumer.

Parameters:

consumer - The consumer to process the existing value.

orElse

default V orElse(V otherValue)

If the value is present, return the value, else return the provided value.

Parameters:

otherValue - The value to return if the property is not present

Returns:

A value

orElseGet

default V orElseGet(Supplier<? extends V> valueSupplier)

If the value is present, return the value, else generate a value given the Supplier.

Parameters:

valueSupplier - The supplier to use to generate a value if the property is not present

Returns:

A value

orElseThrow

default <E extends Throwable> V orElseThrow(Supplier<? extends E> exceptionSupplier)
                                     throws E extends Throwable

If the value is present, return the value, else throw the exception generated by the Supplier.

Type Parameters:

E - The exception type

Parameters:

exceptionSupplier - The supplier to generate an exception if the property is not present

Returns:

A value

Throws:

E - if the property is not present, the exception is thrown

E extends Throwable

element

Element element()

Get the element that this property is associated with.

Returns:

The element associated with this property (i.e. Vertex, Edge, or VertexProperty).

remove

void remove()

Remove the property from the associated element.

empty

static <V> Property<V> empty()

Create an empty property that is not present.

Type Parameters:

V - The value class of the empty property

Returns:

A property that is not present