groovy.util
Class Node

java.lang.Object
  groovy.util.Node

All Implemented Interfaces:

Serializable

public class Node
extends Object
implements Serializable

Represents an arbitrary tree node which can be used for structured metadata or any arbitrary XML-like tree. A node can have a name, a value and an optional Map of attributes. Typically the name is a String and a value is either a String or a List of other Nodes, though the types are extensible to provide a flexible structure, e.g. you could use a QName as the name which includes a namespace URI and a local name. Or a JMX ObjectName etc. So this class can represent metadata like {foo a=1 b="abc"} or nested metadata like {foo a=1 b="123" { bar x=12 text="hello" }}

Author:

James Strachan, Paul King

See Also:

Serialized Form

Constructor Summary

Node(Node parent, Object name)
Creates a new Node named name and if a parent is supplied, adds the newly created node as a child of the parent.

Node(Node parent, Object name, Map attributes)
Creates a new Node named name with attributes specified in the attributes Map.

Node(Node parent, Object name, Map attributes, Object value)
Creates a new Node named name with value value and with attributes specified in the attributes Map.

Node(Node parent, Object name, Object value)
Creates a new Node named name with value value and if a parent is supplied, adds the newly created node as a child of the parent.

Method Summary

boolean	append(Node child) Appends a child to the current node.
Node	appendNode(Object name) Creates a new node as a child of the current node.
Node	appendNode(Object name, Map attributes) Creates a new node as a child of the current node.
Node	appendNode(Object name, Map attributes, Object value) Creates a new node as a child of the current node.
Node	appendNode(Object name, Object value) Creates a new node as a child of the current node.
Object	attribute(Object key) Provides lookup of attributes by key.
Map	attributes() Returns a Map of the attributes of the node or an empty Map if the node does not have any attributes.
List	breadthFirst() Provides a collection of all the nodes in the tree using a breadth-first traversal.
List	children() Returns a List of the nodes children.
List	depthFirst() Provides a collection of all the nodes in the tree using a depth first traversal.
Object	get(String key) Provides lookup of elements by non-namespaced name
NodeList	getAt(QName name) Provides lookup of elements by QName.
Iterator	iterator() Returns an Iterator of the children of the node.
Object	name() Returns an Object representing the name of the node.
Node	parent() Returns the parent of the node.
void	plus(Closure c) Adds sibling nodes (defined using builder-style notation via a Closure) after the current node.
void	print(PrintWriter out) Writes the node to the specified PrintWriter.
boolean	remove(Node child) Removes a child of the current node.
Node	replaceNode(Closure c) Replaces the current node with nodes defined using builder-style notation via a Closure.
protected static void	setMetaClass(MetaClass metaClass, Class nodeClass) Extension point for subclasses to override the metaclass.
protected void	setParent(Node parent) Adds or replaces the parent of the node.
void	setValue(Object value) Adds or replaces the value of the node.
String	text() Returns the textual representation of the current node and all its child nodes.
String	toString()
Object	value() Returns an Object representing the value of the node.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Node

public Node(Node parent,
            Object name)

Creates a new Node named name and if a parent is supplied, adds the newly created node as a child of the parent.

Parameters:

parent - the parent node or null if no parent

name - the name of the node

Node

public Node(Node parent,
            Object name,
            Object value)

Creates a new Node named name with value value and if a parent is supplied, adds the newly created node as a child of the parent.

Parameters:

parent - the parent node or null if no parent

name - the name of the node

value - the Node value, e.g. some text but in general any Object

Node

public Node(Node parent,
            Object name,
            Map attributes)

Creates a new Node named name with attributes specified in the attributes Map. If a parent is supplied, the newly created node is added as a child of the parent.

Parameters:

parent - the parent node or null if no parent

name - the name of the node

attributes - a Map of name-value pairs

Node

public Node(Node parent,
            Object name,
            Map attributes,
            Object value)

Creates a new Node named name with value value and with attributes specified in the attributes Map. If a parent is supplied, the newly created node is added as a child of the parent.

Parameters:

parent - the parent node or null if no parent

name - the name of the node

attributes - a Map of name-value pairs

value - the Node value, e.g. some text but in general any Object

Method Detail

append

public boolean append(Node child)

Appends a child to the current node.

Parameters:

child - the child to append

Returns:

true

remove

public boolean remove(Node child)

Removes a child of the current node.

Parameters:

child - the child to remove

Returns:

true if the param was a child of the current node

appendNode

public Node appendNode(Object name,
                       Map attributes)

Creates a new node as a child of the current node.

Parameters:

name - the name of the new node

attributes - the attributes of the new node

Returns:

the newly created Node

appendNode

public Node appendNode(Object name)

Creates a new node as a child of the current node.

Parameters:

name - the name of the new node

Returns:

the newly created Node

appendNode

public Node appendNode(Object name,
                       Object value)

Creates a new node as a child of the current node.

Parameters:

name - the name of the new node

value - the value of the new node

Returns:

the newly created Node

appendNode

public Node appendNode(Object name,
                       Map attributes,
                       Object value)

Creates a new node as a child of the current node.

Parameters:

name - the name of the new node

attributes - the attributes of the new node

value - the value of the new node

Returns:

the newly created Node

replaceNode

public Node replaceNode(Closure c)

Replaces the current node with nodes defined using builder-style notation via a Closure.

Parameters:

c - A Closure defining the new nodes using builder-style notation.

Returns:

the last appended node

plus

public void plus(Closure c)

Adds sibling nodes (defined using builder-style notation via a Closure) after the current node.

Parameters:

c - A Closure defining the new sibling nodes to add using builder-style notation.

setMetaClass

protected static void setMetaClass(MetaClass metaClass,
                                   Class nodeClass)

Extension point for subclasses to override the metaclass. The default one supports the property and @ attribute notations.

Parameters:

metaClass - the original metaclass

nodeClass - the class whose metaclass we wish to override (this class or a subclass)

text

public String text()

Returns the textual representation of the current node and all its child nodes.

Returns:

the text value of the node including child text

iterator

public Iterator iterator()

Returns an Iterator of the children of the node.

Returns:

the iterator of the nodes children

children

public List children()

Returns a List of the nodes children.

Returns:

the nodes children

attributes

public Map attributes()

Returns a Map of the attributes of the node or an empty Map if the node does not have any attributes.

Returns:

the attributes of the node

attribute

public Object attribute(Object key)

Provides lookup of attributes by key.

Parameters:

key - the key of interest

Returns:

the attribute matching the key or null if no match exists

name

public Object name()

Returns an Object representing the name of the node.

Returns:

the name or null if name is empty

value

public Object value()

Returns an Object representing the value of the node.

Returns:

the value or null if value is empty

setValue

public void setValue(Object value)

Adds or replaces the value of the node.

Parameters:

value - the new value of the node

parent

public Node parent()

Returns the parent of the node.

Returns:

the parent or null for the root node

setParent

protected void setParent(Node parent)

Adds or replaces the parent of the node.

Parameters:

parent - the new parent of the node

get

public Object get(String key)

Provides lookup of elements by non-namespaced name

Parameters:

key - the name (or shortcut key) of the node(s) of interest

Returns:

the nodes which match key

getAt

public NodeList getAt(QName name)

Provides lookup of elements by QName.

Parameters:

name - the QName of interest

Returns:

the nodes matching name

depthFirst

public List depthFirst()

Provides a collection of all the nodes in the tree using a depth first traversal.

Returns:

the list of (depth-first) ordered nodes

breadthFirst

public List breadthFirst()

Provides a collection of all the nodes in the tree using a breadth-first traversal.

Returns:

the list of (breadth-first) ordered nodes

toString

public String toString()

Overrides:

toString in class Object

print

public void print(PrintWriter out)

Writes the node to the specified PrintWriter.

Parameters:

out - the writer receiving the output