org.gcube.data.tr.neo.nodes

Class PersistentNode

java.lang.Object

org.gcube.data.trees.data.Node

org.gcube.data.trees.data.InnerNode

org.gcube.data.tr.neo.nodes.PersistentNode

public class PersistentNode
extends org.gcube.data.trees.data.InnerNode

An InnerNode with persistent state.

Persistent nodes load their state on demand, i.e. when access is required. This optimises partial tree traversals, such as those performed to prune the results of read operations or to update trees in place.

Persistent nodes that are created in READ mode, do not persist state changes. Those that are created in UPDATE mode do. This side-effect is visible to clients to the extent that new nodes acquire identifiers. The following example captures the implications:

 PersistentNode node =..
 Edge e = ....
 node.add(e);
 assertFalse(node.remove(e));
 

Author:

Fabio Simeoni

Nested Class Summary

Nested classes/interfaces inherited from class org.gcube.data.trees.data.Node

org.gcube.data.trees.data.Node.State

Constructor Summary

Constructors

Constructor and Description
PersistentNode(org.neo4j.graphdb.GraphDatabaseService db, org.gcube.data.trees.data.InnerNode node) Creates an instance in BindingMode.ADD that persists an InnerNode, assigning an identifier to it and its descendants.
PersistentNode(org.neo4j.graphdb.GraphDatabaseService db, org.neo4j.graphdb.Node dbnode, BindingMode mode) Creates an instance over a database node, in a given binding mode.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(org.gcube.data.trees.data.Edge e)
Map<QName,String>	attributes()
org.neo4j.graphdb.Node	dbnode() Returns the database node that acts as the entry point to the persistent state of this node
void	delete()
List<org.gcube.data.trees.data.Edge>	edges()
boolean	equals(Object obj)
int	hashCode()
boolean	remove(org.gcube.data.trees.data.Edge e)
String	removeAttribute(QName name)
String	setAttribute(QName name, String value)

Methods inherited from class org.gcube.data.trees.data.InnerNode

add, add, child, child, child, child, child, child, children, children, children, children, children, children, children, children, clearState, delta, descendant, descendant, descendants, descendants, descendants, descendants, edge, edge, edge, edges, edges, edges, find, find, hasEdge, hasEdge, hasEdge, labels, labels, markAsNew, remove, remove, remove, remove, size, toString, update

Methods inherited from class org.gcube.data.trees.data.Node

ancestors, ancestorsAndSelf, attribute, attribute, hasAttribute, hasAttribute, id, parent, removeAttribute, setAttribute, setParent, state, state, uri, uri

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

PersistentNode

public PersistentNode(org.neo4j.graphdb.GraphDatabaseService db,
              org.gcube.data.trees.data.InnerNode node)
               throws IllegalArgumentException

Creates an instance in BindingMode.ADD that persists an InnerNode, assigning an identifier to it and its descendants.

This works as a copy constructor with side-effects in the database. As it clones the node in memory, it also serialises its state in the database.

Parameters:

the - database

node - the node

Throws:

IllegalArgumentException - if the input has already an identifier.

PersistentNode

public PersistentNode(org.neo4j.graphdb.GraphDatabaseService db,
              org.neo4j.graphdb.Node dbnode,
              BindingMode mode)

Creates an instance over a database node, in a given binding mode.

Parameters:

db - the database

dbnode - the database node

mode - the binding mode

Method Detail

dbnode

public org.neo4j.graphdb.Node dbnode()

Returns the database node that acts as the entry point to the persistent state of this node

Returns:

the database node

attributes

public Map<QName,String> attributes()

Overrides:

attributes in class org.gcube.data.trees.data.Node

setAttribute

public String setAttribute(QName name,
                  String value)

Overrides:

setAttribute in class org.gcube.data.trees.data.Node

removeAttribute

public String removeAttribute(QName name)

Overrides:

removeAttribute in class org.gcube.data.trees.data.Node

edges

public List<org.gcube.data.trees.data.Edge> edges()

Overrides:

edges in class org.gcube.data.trees.data.InnerNode

add

public boolean add(org.gcube.data.trees.data.Edge e)

Overrides:

add in class org.gcube.data.trees.data.InnerNode

remove

public boolean remove(org.gcube.data.trees.data.Edge e)

Overrides:

remove in class org.gcube.data.trees.data.InnerNode

delete

public void delete()

Overrides:

delete in class org.gcube.data.trees.data.InnerNode

equals

public boolean equals(Object obj)

Overrides:

equals in class org.gcube.data.trees.data.InnerNode

hashCode

public int hashCode()

Overrides:

hashCode in class org.gcube.data.trees.data.InnerNode