org.w3c.dom.traversal
Interface NodeFilter

public interface NodeFilter

Filters are objects that know how to "filter out" nodes. If a NodeIterator or TreeWalker is given a NodeFilter, it applies the filter before it returns the next node. If the filter says to accept the node, the traversal logic returns it; otherwise, traversal looks for the next node and pretends that the node that was rejected was not there.

The DOM does not provide any filters. NodeFilter is just an interface that users can implement to provide their own filters.

NodeFilters do not need to know how to traverse from node to node, nor do they need to know anything about the data structure that is being traversed. This makes it very easy to write filters, since the only thing they have to know how to do is evaluate a single node. One filter may be used with a number of different kinds of traversals, encouraging code reuse.

See also the Document Object Model (DOM) Level 2 Traversal and Range Specification.

Since:

DOM Level 2

Field Summary

static short	FILTER_ACCEPT Accept the node.
static short	FILTER_REJECT Reject the node.
static short	FILTER_SKIP Skip this single node.
static int	SHOW_ALL Show all Nodes.
static int	SHOW_ATTRIBUTE Show Attr nodes.
static int	SHOW_CDATA_SECTION Show CDATASection nodes.
static int	SHOW_COMMENT Show Comment nodes.
static int	SHOW_DOCUMENT Show Document nodes.
static int	SHOW_DOCUMENT_FRAGMENT Show DocumentFragment nodes.
static int	SHOW_DOCUMENT_TYPE Show DocumentType nodes.
static int	SHOW_ELEMENT Show Element nodes.
static int	SHOW_ENTITY Show Entity nodes.
static int	SHOW_ENTITY_REFERENCE Show EntityReference nodes.
static int	SHOW_NOTATION Show Notation nodes.
static int	SHOW_PROCESSING_INSTRUCTION Show ProcessingInstruction nodes.
static int	SHOW_TEXT Show Text nodes.

Method Summary

short

acceptNode(Node n) Test whether a specified node is visible in the logical view of a TreeWalker or NodeIterator.

Field Detail

FILTER_ACCEPT

public static final short FILTER_ACCEPT

Accept the node. Navigation methods defined for NodeIterator or TreeWalker will return this node.

FILTER_REJECT

public static final short FILTER_REJECT

Reject the node. Navigation methods defined for NodeIterator or TreeWalker will not return this node. For TreeWalker, the children of this node will also be rejected. NodeIterators treat this as a synonym for FILTER_SKIP.

FILTER_SKIP

public static final short FILTER_SKIP

Skip this single node. Navigation methods defined for NodeIterator or TreeWalker will not return this node. For both NodeIterator and TreeWalker, the children of this node will still be considered.

SHOW_ALL

public static final int SHOW_ALL

Show all Nodes.

SHOW_ATTRIBUTE

public static final int SHOW_ATTRIBUTE

Show Attr nodes. This is meaningful only when creating an NodeIterator or TreeWalker with an attribute node as its root; in this case, it means that the attribute node will appear in the first position of the iteration or traversal. Since attributes are never children of other nodes, they do not appear when traversing over the document tree.

SHOW_CDATA_SECTION

public static final int SHOW_CDATA_SECTION

Show CDATASection nodes.

SHOW_COMMENT

public static final int SHOW_COMMENT

Show Comment nodes.

SHOW_DOCUMENT

public static final int SHOW_DOCUMENT

Show Document nodes.

SHOW_DOCUMENT_FRAGMENT

public static final int SHOW_DOCUMENT_FRAGMENT

Show DocumentFragment nodes.

SHOW_DOCUMENT_TYPE

public static final int SHOW_DOCUMENT_TYPE

Show DocumentType nodes.

SHOW_ELEMENT

public static final int SHOW_ELEMENT

Show Element nodes.

SHOW_ENTITY

public static final int SHOW_ENTITY

Show Entity nodes. This is meaningful only when creating an NodeIterator or TreeWalker with an Entity node as its root; in this case, it means that the Entity node will appear in the first position of the traversal. Since entities are not part of the document tree, they do not appear when traversing over the document tree.

SHOW_ENTITY_REFERENCE

public static final int SHOW_ENTITY_REFERENCE

Show EntityReference nodes.

SHOW_NOTATION

public static final int SHOW_NOTATION

Show Notation nodes. This is meaningful only when creating an NodeIterator or TreeWalker with a Notation node as its root; in this case, it means that the Notation node will appear in the first position of the traversal. Since notations are not part of the document tree, they do not appear when traversing over the document tree.

SHOW_PROCESSING_INSTRUCTION

public static final int SHOW_PROCESSING_INSTRUCTION

Show ProcessingInstruction nodes.

SHOW_TEXT

public static final int SHOW_TEXT

Show Text nodes.

Method Detail

acceptNode

public short acceptNode(Node n)

Test whether a specified node is visible in the logical view of a TreeWalker or NodeIterator. This function will be called by the implementation of TreeWalker and NodeIterator; it is not normally called directly from user code. (Though you could do so if you wanted to use the same filter to guide your own application logic.)

Parameters:

n - The node to check to see if it passes the filter or not.

Returns:

A constant to determine whether the node is accepted, rejected, or skipped, as defined above.