nu.xom

Class ParentNode

Object

nu.xom.Node

nu.xom.ParentNode

Direct Known Subclasses:

Document, Element

public abstract class ParentNode
extends Node

The generic superclass for nodes that have children. Not counting subclasses, there are exactly two such public classes in XOM:

• Document
• Element

This class provides methods to add and remove child nodes.

Version:

1.3.0

Author:

Elliotte Rusty Harold

Method Summary

Modifier and Type	Method and Description
void	appendChild(Node child) Appends a node to the children of this node.
Node	getChild(int position) Returns the child of this node at the specified position.
int	getChildCount() Returns the number of child nodes this node contains.
int	indexOf(Node child) Returns the position of a node within the children of this node.
void	insertChild(Node child, int position) Inserts a child node at the specified position.
Node	removeChild(int position) Removes the child of this node at the specified position.
Node	removeChild(Node child) Removes the specified child of this node.
void	replaceChild(Node oldChild, Node newChild) Replaces an existing child with a new child node.
abstract void	setBaseURI(String URI) Sets the URI against which relative URIs in this node will be resolved.

Methods inherited from class nu.xom.Node

copy, detach, equals, getBaseURI, getDocument, getParent, getValue, hashCode, query, query, toXML

Methods inherited from class Object

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

Method Detail

getChildCount

public int getChildCount()

Returns the number of child nodes this node contains. This is always greater than or equal to 0.

Specified by:

getChildCount in class Node

Returns:

the number of children of this node

insertChild

public void insertChild(Node child,
                        int position)

Inserts a child node at the specified position. The child node previously at that position (if any) and all subsequent child nodes are moved up by one. That is, when inserting a node at 2, the old node at 2 is moved to 3, the old child at 3 is moved to 4, and so forth. Inserting at position 0 makes the child the first child of this node. Inserting at the position getChildCount() makes the child the last child of the node.

All the other methods that add a node to the tree ultimately invoke this method.

Parameters:

position - where to insert the child

child - the node to insert

Throws:

IllegalAddException - if this node cannot have a child of the argument's type

MultipleParentException - if child already has a parent

NullPointerException - if child is null

IndexOutOfBoundsException - if the position is negative or greater than the number of children of this node

appendChild

public void appendChild(Node child)

Appends a node to the children of this node.

Parameters:

child - node to append to this node

Throws:

IllegalAddException - if this node cannot have children of this type

MultipleParentException - if child already has a parent

NullPointerException - if child is null

getChild

public Node getChild(int position)

Returns the child of this node at the specified position. Indexes begin at 0 and count up to one less than the number of children in this node.

Specified by:

getChild in class Node

Parameters:

position - index of the node to return

Returns:

the node at the requested position

Throws:

IndexOutOfBoundsException - if the index is negative or greater than or equal to the number of children of this node

indexOf

public int indexOf(Node child)

Returns the position of a node within the children of this node. This is a number between 0 and one less than the number of children of this node. It returns -1 if child does not have this node as a parent.

This method does a linear search through the node's children. On average, it executes in O(N) where N is the number of children of the node.

Parameters:

child - the node whose position is desired

Returns:

the position of the argument node among the children of this node

removeChild

public Node removeChild(int position)

Removes the child of this node at the specified position. Indexes begin at 0 and count up to one less than the number of children in this node.

Parameters:

position - index of the node to remove

Returns:

the node which was removed

Throws:

IndexOutOfBoundsException - if the index is negative or greater than or equal to the number of children of this node

removeChild

public Node removeChild(Node child)

Removes the specified child of this node.

Parameters:

child - child node to remove

Returns:

the node which was removed

Throws:

NoSuchChildException - if child is not in fact a child of this node

replaceChild

public void replaceChild(Node oldChild,
                         Node newChild)

Replaces an existing child with a new child node. If oldChild is not a child of this node, then a NoSuchChildException is thrown.

Parameters:

oldChild - the node removed from the tree

newChild - the node inserted into the tree

Throws:

MultipleParentException - if newChild already has a parent

NoSuchChildException - if oldChild is not a child of this node

NullPointerException - if either argument is null

IllegalAddException - if this node cannot have children of the type of newChild

setBaseURI

public abstract void setBaseURI(String URI)

Sets the URI against which relative URIs in this node will be resolved. Generally, it's only necessary to set this property if it's different from a node's parent's base URI, as it may be in a document assembled from multiple entities or by XInclude.

Relative URIs are not allowed here. Base URIs must be absolute. However, the base URI may be set to null or the empty string to indicate that the node has no explicit base URI. In this case, it inherits the base URI of its parent node, if any.

URIs with fragment identifiers are also not allowed. The value passed to this method must be a pure URI, not a URI reference.

You can also add an xml:base attribute to an element in the same way you'd add any other namespaced attribute to an element. If an element's base URI conflicts with its xml:base attribute, then the value found in the xml:base attribute is used.

If the base URI is null or the empty string and there is no xml:base attribute, then the base URI is determined by the nearest ancestor node which does have a base URI. Moving such a node from one location to another can change its base URI.

Parameters:

URI - the new base URI for this node

Throws:

MalformedURIException - if URI is not a legal RFC 3986 absolute URI