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 shortFILTER_ACCEPT
Accept the node.
static shortFILTER_REJECT
Reject the node.
static shortFILTER_SKIP
Skip this single node.
static intSHOW_ALL
Show all Nodes.
static intSHOW_ATTRIBUTE
Show Attr nodes.
static intSHOW_CDATA_SECTION
Show CDATASection nodes.
static intSHOW_COMMENT
Show Comment nodes.
static intSHOW_DOCUMENT
Show Document nodes.
static intSHOW_DOCUMENT_FRAGMENT
Show DocumentFragment nodes.
static intSHOW_DOCUMENT_TYPE
Show DocumentType nodes.
static intSHOW_ELEMENT
Show Element nodes.
static intSHOW_ENTITY
Show Entity nodes.
static intSHOW_ENTITY_REFERENCE
Show EntityReference nodes.
static intSHOW_NOTATION
Show Notation nodes.
static intSHOW_PROCESSING_INSTRUCTION
Show ProcessingInstruction nodes.
static intSHOW_TEXT
Show Text nodes.
Method Summary
shortacceptNode(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.