org.gcube.data.trees.data
Class Node

java.lang.Object
  org.gcube.data.trees.data.Node

Direct Known Subclasses:

InnerNode, Leaf

public abstract class Node
extends Object

A tree node.

Author:

Fabio Simeoni

Nested Class Summary

static class

Node.State Enumerates the state of the node with respect to remote storage.

Constructor Summary

	Node() Creates an instance.
protected	Node(String id)
protected	Node(String i, Node.State s, Map<QName,String> as)

Method Summary

List<InnerNode>	ancestors() Returns the ancestors of the node.
List<Node>	ancestorsAndSelf() Returns the ancestors of the node along with the node itself.
String	attribute(QName name) Returns the value of an attribute with a given name.
String	attribute(String name) Returns the value of an attribute with a given name.
Map<QName,String>	attributes() Returns (a copy of) the node attributes.
void	delete() Marks the node as Node.State.DELETED, removing all its attributes.
protected Node	delta(Node future) Returns a node that reflects the delta between this node and a given input node.
boolean	equals(Object obj)
boolean	hasAttribute(QName name) Indicates whether the node has an attribute with a given name.
boolean	hasAttribute(String name) Indicates whether the node has an attribute with a given name.
int	hashCode()
String	id() Returns the node identifier.
InnerNode	parent() Returns the parent of the node.
String	removeAttribute(QName name) Removes an attribute from the node, if it exists.
String	removeAttribute(String name) Removes an attribute from the node, if it exists.
String	setAttribute(QName name, String value) Sets the value of a given node attribute, or adds the attribute if it does not exist already.
String	setAttribute(String name, String value) Sets the value of a given node attribute, or adds the attribute if it does not exist already.
protected void	setParent(InnerNode p) Sets the parent of the node.
abstract long	size() Returns the size of the tree rooted in this node, in bytes.
Node.State	state() Returns the node state.
protected void	state(Node.State s)
void	update(Node delta) Applies the changes captured by the delta node in input..

Methods inherited from class java.lang.Object

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

Constructor Detail

Node

public Node()

Creates an instance.

Node

protected Node(String id)

Node

protected Node(String i,
               Node.State s,
               Map<QName,String> as)

Method Detail

size

public abstract long size()

Returns the size of the tree rooted in this node, in bytes.

Returns:

the size.

id

public String id()

Returns the node identifier.

Returns:

the identifier.

attributes

public Map<QName,String> attributes()

Returns (a copy of) the node attributes.

Returns:

the attributes.

setAttribute

public String setAttribute(QName name,
                           String value)

Sets the value of a given node attribute, or adds the attribute if it does not exist already.

Parameters:

name - the name of the attribute.

value - the value of the attribute.

Returns:

the previous value of the attribute, or null if the attribute does not exist already.

setAttribute

public String setAttribute(String name,
                           String value)
                    throws IllegalArgumentException

Sets the value of a given node attribute, or adds the attribute if it does not exist already.

Parameters:

name - the local name of the attribute.

value - the value of the attribute.

Returns:

the previous value of the attribute, or null if the attribute does not exist already.

Throws:

IllegalArgumentException - if the local name of the attribute is null.

removeAttribute

public String removeAttribute(QName name)

Removes an attribute from the node, if it exists.

Parameters:

name - the name of the attribute.

Returns:

the value of the attribute, or null if the attribute does not exist.

Throws:

IllegalStateException - if the nodes does not have an attribute with the given name.

removeAttribute

public String removeAttribute(String name)
                       throws IllegalStateException,
                              IllegalArgumentException

Removes an attribute from the node, if it exists.

Parameters:

name - the local name of the attribute.

Returns:

the value of the attribute, or null if the attribute does not exist.

Throws:

IllegalStateException - if the nodes does not have an attribute with the given name.

IllegalArgumentException - if the local name of the attribute is null.

attribute

public String attribute(QName name)
                 throws IllegalStateException

Returns the value of an attribute with a given name.

Parameters:

name - the name.

Returns:

the value.

Throws:

IllegalStateException - if an attribute with the given name does not exist.

attribute

public String attribute(String name)
                 throws IllegalStateException,
                        IllegalArgumentException

Returns the value of an attribute with a given name.

Parameters:

name - the local name of the attribute.

Returns:

the value.

Throws:

IllegalStateException - if an attribute with the given name does not exist.

IllegalArgumentException - if the local name of the attribute is null.

hasAttribute

public boolean hasAttribute(QName name)

Indicates whether the node has an attribute with a given name.

Parameters:

name - the name.

Returns:

true if it does, false otherwise.

hasAttribute

public boolean hasAttribute(String name)
                     throws IllegalArgumentException

Indicates whether the node has an attribute with a given name.

Parameters:

name - the name.

Returns:

true if it does, false otherwise.

Throws:

IllegalArgumentException - if the local name of the attribute is null.

state

public Node.State state()

Returns the node state.

Returns:

the state.

state

protected void state(Node.State s)

delete

public void delete()

Marks the node as Node.State.DELETED, removing all its attributes.

update

public void update(Node delta)
            throws IllegalStateException,
                   IllegalArgumentException

Applies the changes captured by the delta node in input..

This operation acts as the inverse of delta(Node). In particular:

removes all the attributes of the delta node with a value of null;

adds all the attributes of the delta node with a non-null value which do no exist in this node;

modifies all the attributes of the delta node that differ in value from those in this node;

Parameters:

delta - the delta node

Throws:

IllegalStateException - if this node has no identifier

IllegalArgumentException - if the delta node has an unexpected state, or its identifier differs form this node's, or more generally its attributes do not relate to those of this node as expected

delta

protected Node delta(Node future)
              throws IllegalStateException,
                     IllegalArgumentException

Returns a node that reflects the delta between this node and a given input node.

The delta node can only be computed if the input node has the same identifier as this node. For all purposes, in fact, the input node is expected to be (or simply look like) a future version of this node, as if it was originally cloned from this node and had evolved since.

Under this assumption, the delta node has:

all the attributes that no longer exist in the input node, but with a null value;

all the attributes of the input node that do not exist in this node;

all the attributes of the input node that differ in value from those in this node;

a state of Node.State.MODIFIED if the attributes of the two nodes are not identical.

Subclasses that extend the comparison to additional pieces of state, must:

• invoke this method via super;
• extend them to the additional pieces of state.

Parameters:

future - the input node.

Throws:

IllegalStateException - if this node has no identifier.

IllegalArgumentException - if this node has no identifier, or a different identifier's from the input node.

setParent

protected void setParent(InnerNode p)

Sets the parent of the node.

Parameters:

p - the parent.

parent

public InnerNode parent()

Returns the parent of the node.

Returns:

the parent.

ancestors

public List<InnerNode> ancestors()

Returns the ancestors of the node.

Returns:

the ancestors.

ancestorsAndSelf

public List<Node> ancestorsAndSelf()

Returns the ancestors of the node along with the node itself.

Returns:

the ancestors.

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object