com.sparsity.dex.algorithms
Class Traversal

java.lang.Object
  extended by com.sparsity.dex.algorithms.Traversal
All Implemented Interfaces:
java.io.Closeable
Direct Known Subclasses:
TraversalBFS, TraversalDFS

public class Traversal
extends java.lang.Object
implements java.io.Closeable

Traversal class.

Any class implementing this abstract class can be used to traverse a graph.

Once the instance has been created and the allowed node and edge types has been set, it can be used as an iterator, retrieving the next object identifier of the traversal until there are no more.

Check out the 'Algorithms' section in the DEX User Manual for more details on this.

Author:
Sparsity Technologies http://www.sparsity-technologies.com

Method Summary
 void addAllEdgeTypes(EdgesDirection d)
          Allows for traversing all edge types of the graph.
 void addAllNodeTypes()
          Allows for traversing all node types of the graph.
 void addEdgeType(int t, EdgesDirection d)
          Allows for traversing edges of the given type.
 void addNodeType(int t)
          Allows for traversing nodes of the given type.
 void close()
          Closes the Traversal instance.
 void excludeEdges(Objects edges)
          Set which edges can't be used.
 void excludeNodes(Objects nodes)
          Set which nodes can't be used.
 int getCurrentDepth()
          Returns the depth of the current node.
 boolean hasNext()
          Gets if there are more objects to be traversed.
 boolean isClosed()
          Gets if Traversal instance has been closed or not.
 long next()
          Gets the next object of the traversal.
 void setMaximumHops(int maxhops)
          Sets the maximum hops restriction.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Method Detail

hasNext

public boolean hasNext()
Gets if there are more objects to be traversed.

Returns:
TRUE if there are more objects, FALSE otherwise.

addEdgeType

public void addEdgeType(int t,
                        EdgesDirection d)
Allows for traversing edges of the given type.

Parameters:
t - [in] Edge type.
d - [in] Edge direction.

addNodeType

public void addNodeType(int t)
Allows for traversing nodes of the given type.

Parameters:
t - null

getCurrentDepth

public int getCurrentDepth()
Returns the depth of the current node.

That is, it returns the depth of the node returned in the last call to Next().

Returns:
The depth of the current node.

excludeEdges

public void excludeEdges(Objects edges)
Set which edges can't be used.

This will replace any previously specified set of excluded edges. Should only be used to exclude the usage of specific edges from allowed edge types because it's less efficient than not allowing an edge type.

Parameters:
edges - [in] A set of edge identifiers that must be kept intact until the destruction of the class.

close

public void close()
Closes the Traversal instance.

It must be called to ensure the integrity of all data.

Specified by:
close in interface java.io.Closeable

addAllNodeTypes

public void addAllNodeTypes()
Allows for traversing all node types of the graph.


addAllEdgeTypes

public void addAllEdgeTypes(EdgesDirection d)
Allows for traversing all edge types of the graph.

Parameters:
d - [in] Edge direction.

excludeNodes

public void excludeNodes(Objects nodes)
Set which nodes can't be used.

This will replace any previously specified set of excluded nodes. Should only be used to exclude the usage of specific nodes from allowed node types because it's less efficient than not allowing a node type.

Parameters:
nodes - [in] A set of node identifiers that must be kept intact until the destruction of the class.

next

public long next()
Gets the next object of the traversal.

Returns:
A node or edge identifier.

setMaximumHops

public void setMaximumHops(int maxhops)
Sets the maximum hops restriction.

All paths longer than the maximum hops restriction will be ignored.

Parameters:
maxhops - [in] The maximum hops restriction. It must be positive or zero. Zero, the default value, means unlimited.

isClosed

public boolean isClosed()
Gets if Traversal instance has been closed or not.

Returns:
TRUE if the Traversal instance has been closed, FALSE otherwise.
See Also:
close()