org.apache.tinkerpop.gremlin.process.traversal

Interface TraversalSideEffects

All Superinterfaces:

Cloneable, Serializable

All Known Implementing Classes:

DefaultTraversalSideEffects, EmptyTraversalSideEffects, VertexTraversalSideEffects

public interface TraversalSideEffects
extends Cloneable, Serializable

Author:

Marko A. Rodriguez (http://markorodriguez.com)

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	TraversalSideEffects.Exceptions

Field Summary

Fields

Modifier and Type	Field and Description
static String	SIDE_EFFECTS

Method Summary

Modifier and Type	Method and Description
TraversalSideEffects	clone() Cloning is used to duplicate the sideEffects typically in OLAP environments.
default boolean	exists(String key) Determines if the TraversalSideEffects contains the respective key.
default <V> void	forEach(BiConsumer<String,V> biConsumer)
<V> V	get(String key) Get the sideEffect associated with the provided key.
default <V> V	getOrCreate(String key, Supplier<V> orCreate) If the sideEffect contains an object associated with the key, return it.
<V> Optional<Supplier<V>>	getRegisteredSupplier(String key) Get the registered Supplier associated with the specified key.
<S> Optional<Supplier<S>>	getSackInitialValue()
<S> Optional<UnaryOperator<S>>	getSackSplitOperator()
default <V> void	ifPresent(String key, Consumer<V> consumer) If a value or registered Supplier exists for the provided key, consume it with the provided consumer.
Set<String>	keys() The keys of the sideEffect which includes registered Supplier keys.
void	mergeInto(TraversalSideEffects sideEffects) Add the current TraversalSideEffects data and suppliers to the provided TraversalSideEffects.
default <V> V	orElse(String key, V otherValue) Return the value associated with the key or return the provided otherValue.
void	registerSupplier(String key, Supplier supplier) Register a Supplier with the provided key.
default void	registerSupplierIfAbsent(String key, Supplier supplier) A helper method to register a Supplier if it has not already been registered.
void	remove(String key) Remove both the value and registered Supplier associated with provided key.
void	set(String key, Object value) Set the specified key to the specified value.
void	setLocalVertex(Vertex vertex) In a distributed GraphComputer traversal, the sideEffects of the traversal are not a single object within a single JVM.
<S> void	setSack(Supplier<S> initialValue, Optional<UnaryOperator<S>> splitOperator)

Field Detail

SIDE_EFFECTS

static final String SIDE_EFFECTS

See Also:

Constant Field Values

Method Detail

exists

default boolean exists(String key)

Determines if the TraversalSideEffects contains the respective key. If the key references a stored Supplier, then it should return true as it will be dynamically created on get().

Parameters:

key - the key to check for

Returns:

whether the key exists in the sideEffects

set

void set(String key,
         Object value)

Set the specified key to the specified value. If a Supplier is provided, it is NOT assumed to be a supplier as set by registerSupplier().

Parameters:

key - the key

value - the value

get

<V> V get(String key)
   throws IllegalArgumentException

Get the sideEffect associated with the provided key. If the sideEffect contains an object for the key, return it. Else if the sideEffect has a registered Supplier for that key, generate the object, store the object in the sideEffects, and return it.

Type Parameters:

V - the type of the value to retrieve

Parameters:

key - the key to get the value for

Returns:

the value associated with key

Throws:

IllegalArgumentException - if the key does not reference an object or a registered supplier.

orElse

default <V> V orElse(String key,
                     V otherValue)

Return the value associated with the key or return the provided otherValue. The otherValue will not be stored in the sideEffect.

Type Parameters:

V - the type of the value to get

Parameters:

key - the key to get the value for

otherValue - if not value is associated with key, return the other value.

Returns:

the value associated with the key or the otherValue

ifPresent

default <V> void ifPresent(String key,
                           Consumer<V> consumer)

If a value or registered Supplier exists for the provided key, consume it with the provided consumer.

Type Parameters:

V - the type of the value to consume

Parameters:

key - the key to the value

consumer - the consumer to process the value

remove

void remove(String key)

Remove both the value and registered Supplier associated with provided key.

Parameters:

key - the key of the value and registered supplier to remove

keys

Set<String> keys()

The keys of the sideEffect which includes registered Supplier keys. In essence, that which is possible to get().

Returns:

the keys of the sideEffect

registerSupplier

void registerSupplier(String key,
                      Supplier supplier)

Register a Supplier with the provided key. When sideEffects get() are called, if no object exists and there exists a registered supplier for the key, the object is generated. Registered suppliers are used for the lazy generation of sideEffect data.

Parameters:

key - the key to register the supplier with

supplier - the supplier that will generate an object when get() is called if it hasn't already been created

getRegisteredSupplier

<V> Optional<Supplier<V>> getRegisteredSupplier(String key)

Get the registered Supplier associated with the specified key.

Type Parameters:

V - The object type of the supplier

Parameters:

key - the key associated with the supplier

Returns:

A non-empty optional if the supplier exists

registerSupplierIfAbsent

default void registerSupplierIfAbsent(String key,
                                      Supplier supplier)

A helper method to register a Supplier if it has not already been registered.

Parameters:

key - the key of the supplier to register

supplier - the supplier to register if the key has not already been registered

setSack

<S> void setSack(Supplier<S> initialValue,
                 Optional<UnaryOperator<S>> splitOperator)

getSackInitialValue

<S> Optional<Supplier<S>> getSackInitialValue()

getSackSplitOperator

<S> Optional<UnaryOperator<S>> getSackSplitOperator()

getOrCreate

default <V> V getOrCreate(String key,
                          Supplier<V> orCreate)

If the sideEffect contains an object associated with the key, return it. Else if a "with" supplier exists for the key, generate the object, store it in the sideEffects and return the object. Else use the provided supplier to generate the object, store it in the sideEffects and return the object. Note that if the orCreate supplier is used, it is NOT registered as a Supplier.

Type Parameters:

V - the return type of the object

Parameters:

key - the key of the object to get

orCreate - if the object doesn't exist as an object or suppliable object, then generate it with the specified supplier

Returns:

the object that is either retrieved, generated, or supplier via orCreate

forEach

default <V> void forEach(BiConsumer<String,V> biConsumer)

setLocalVertex

void setLocalVertex(Vertex vertex)

In a distributed GraphComputer traversal, the sideEffects of the traversal are not a single object within a single JVM. Instead, the sideEffects are distributed across the graph and the pieces are stored on the computing vertices. This method is necessary to call when the Traversal is processing the Traversers at a particular Vertex.

Parameters:

vertex - the vertex where the traversal is currently executing.

clone

TraversalSideEffects clone()

Cloning is used to duplicate the sideEffects typically in OLAP environments.

Returns:

The cloned sideEffects

mergeInto

void mergeInto(TraversalSideEffects sideEffects)

Add the current TraversalSideEffects data and suppliers to the provided TraversalSideEffects.

Parameters:

sideEffects - the sideEffects to add this traversal's sideEffect data to.