Traversal (Gremlin Core: The Primary Components of TinkerPop3 3.0.0.M7 API)

All Superinterfaces:

java.lang.Cloneable, java.util.Iterator<E>

All Known Subinterfaces:

GraphTraversal<S,E>, GraphTraversal.Admin<S,E>, Traversal.Admin<S,E>

All Known Implementing Classes:

DefaultGraphTraversal, DefaultTraversal, EmptyGraphTraversal, EmptyTraversal
```
public interface Traversal<S,E>
extends java.util.Iterator<E>, java.lang.Cloneable
```
A Traversal represents a directed walk over a Graph. This is the base interface for all traversal's, where each extending interface is seen as a domain specific language. For example, GraphTraversal is a domain specific language for traversing a graph using "graph concepts" (e.g. vertices, edges). Another example may represent the graph using "social concepts" (e.g. people, cities, artifacts). A Traversal is evaluated in one of two ways: TraversalEngine.STANDARD (OLTP) and TraversalEngine.COMPUTER (OLAP). OLTP traversals leverage an iterator and are executed within a single JVM (with data access allowed to be remote). OLAP traversals leverage GraphComputer and are executed between multiple JVMs (and/or cores).

Author:

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

Nested Class Summary

Nested Classes
Modifier and Type	Interface and Description
`static interface`	`Traversal.Admin<S,E>`
`static class`	`Traversal.Exceptions` A collection of `Exception` types associated with Traversal execution.

Field Summary

Fields
Modifier and Type Field and Description

static java.lang.String OF
Used for reflection based access to the static "of" method of a Traversal.

Fields
Modifier and Type	Field and Description
`static java.lang.String`	`OF` Used for reflection based access to the static "of" method of a Traversal.

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`Traversal.Admin<S,E>`	`asAdmin()` Get access to administrative methods of the traversal via its accompanying `Traversal.Admin`.
`Traversal<S,E>`	`clone()` Cloning is used to duplicate the traversal typically in OLAP environments.
`default <C extends java.util.Collection<E>> C`	`fill(C collection)` Add all the results of the traversal to the provided collection.
`default <E2> void`	`forEachRemaining(java.lang.Class<E2> endType, java.util.function.Consumer<E2> consumer)` A traversal can be rewritten such that its defined end type E may yield objects of a different type.
`default <A,B> Traversal<A,B>`	`iterate()` Iterate all the `Traverser` instances in the traversal.
`default java.util.List<E>`	`next(int amount)` Get the next n-number of results from the traversal.
`default Traversal<S,E>`	`submit(GraphComputer computer)` Submit the traversal to a `GraphComputer` for OLAP execution.
`default BulkSet<E>`	`toBulkSet()` Put all the results into a `BulkSet`.
`default java.util.List<E>`	`toList()` Put all the results into an `ArrayList`.
`default java.util.Set<E>`	`toSet()` Put all the results into a `HashSet`.
`default java.util.Optional<E>`	`tryNext()` Return an `Optional` of the next E object in the traversal.

Methods inherited from interface java.util.Iterator
forEachRemaining, hasNext, next, remove

- Field Detail
  - OF
```
static final java.lang.String OF
```
    Used for reflection based access to the static "of" method of a Traversal.
    
    See Also:
    
    Constant Field Values
- Method Detail
  - asAdmin
```
Traversal.Admin<S,E> asAdmin()
```
    Get access to administrative methods of the traversal via its accompanying Traversal.Admin.
    
    Returns:
    
    the admin of this traversal
  - submit
```
default Traversal<S,E> submit(GraphComputer computer)
```
    Submit the traversal to a GraphComputer for OLAP execution. This method should apply the traversal strategies for TraversalEngine.COMPUTER. Then register and execute the traversal via TraversalVertexProgram. Then wrap the ComputerResult in a new Traversal containing a ComputerResultStep.
    
    Parameters:
    
    computer - the GraphComputer to execute the traversal on
    
    Returns:
    
    a new traversal with the starts being the results of the TraversalVertexProgram
  - tryNext
```
default java.util.Optional<E> tryNext()
```
    Return an Optional of the next E object in the traversal. If the traversal is empty, then an Optional.empty() is returned.
    
    Returns:
    
    an optional of the next object in the traversal
  - next
```
default java.util.List<E> next(int amount)
```
    Get the next n-number of results from the traversal.
    
    Parameters:
    
    amount - the number of results to get
    
    Returns:
    
    the n-results in a List
  - toList
```
default java.util.List<E> toList()
```
    Put all the results into an ArrayList.
    
    Returns:
    
    the results in a list
  - toSet
```
default java.util.Set<E> toSet()
```
    Put all the results into a HashSet.
    
    Returns:
    
    the results in a set
  - toBulkSet
```
default BulkSet<E> toBulkSet()
```
    Put all the results into a BulkSet. This can reduce both time and space when aggregating results by ensuring a weighted set.
    
    Returns:
    
    the results in a bulk set
  - fill
```
default <C extends java.util.Collection<E>> C fill(C collection)
```
    Add all the results of the traversal to the provided collection.
    
    Parameters:
    
    collection - the collection to fill
    
    Returns:
    
    the collection now filled
  - iterate
```
default <A,B> Traversal<A,B> iterate()
```
    Iterate all the Traverser instances in the traversal. What is returned is the empty traversal. It is assumed that what is desired from the computation is are the sideEffects yielded by the traversal.
    
    Returns:
    
    the fully drained traversal
  - forEachRemaining
```
default <E2> void forEachRemaining(java.lang.Class<E2> endType,
                                   java.util.function.Consumer<E2> consumer)
```
    A traversal can be rewritten such that its defined end type E may yield objects of a different type. This helper method allows for the casting of the output to the known the type.
    
    Type Parameters:
    
    E2 - the known output type of the traversal
    
    Parameters:
    
    endType - the true output type of the traversal
    
    consumer - a Consumer to process each output
  - clone
```
Traversal<S,E> clone()
              throws java.lang.CloneNotSupportedException
```
    Cloning is used to duplicate the traversal typically in OLAP environments.
    
    Returns:
    
    The cloned traversal
    
    Throws:
    
    java.lang.CloneNotSupportedException

Interface Traversal<S,E>

Nested Class Summary

Field Summary

Method Summary

Methods inherited from interface java.util.Iterator

Field Detail

OF

Method Detail

asAdmin

submit

tryNext

next

toList

toSet

toBulkSet

fill

iterate

forEachRemaining

clone