NodeIterator (Common DOM API) - JDK 5 Documentation v6.0, Java 2 SDK 英文文档

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org.w3c.dom.traversal
Interface NodeIterator

public interface NodeIterator

NodeIterators are used to step through a set of nodes, e.g. the set of nodes in a NodeList, the document subtree governed by a particular Node, the results of a query, or any other set of nodes. The set of nodes to be iterated is determined by the implementation of the NodeIterator. DOM Level 2 specifies a single NodeIterator implementation for document-order traversal of a document subtree. Instances of these NodeIterators are created by calling DocumentTraversal.createNodeIterator().

Since:: DOM Level 2

Method Summary

void detach()
          Detaches the NodeIterator from the set which it iterated over, releasing any computational resources and placing the NodeIterator in the INVALID state.

boolean getExpandEntityReferences()
          The value of this flag determines whether the children of entity reference nodes are visible to the NodeIterator.

NodeFilter getFilter()
          The NodeFilter used to screen nodes.

Node getRoot()
          The root node of the NodeIterator, as specified when it was created.

int getWhatToShow()
          This attribute determines which node types are presented via the NodeIterator.

Node nextNode()
          Returns the next node in the set and advances the position of the NodeIterator in the set.

Node previousNode()
          Returns the previous node in the set and moves the position of the NodeIterator backwards in the set.

Method Summary
`void`	`detach()` Detaches the `NodeIterator` from the set which it iterated over, releasing any computational resources and placing the `NodeIterator` in the INVALID state.
`boolean`	`getExpandEntityReferences()` The value of this flag determines whether the children of entity reference nodes are visible to the `NodeIterator`.
`NodeFilter`	`getFilter()` The `NodeFilter` used to screen nodes.
`Node`	`getRoot()` The root node of the `NodeIterator`, as specified when it was created.
`int`	`getWhatToShow()` This attribute determines which node types are presented via the `NodeIterator`.
`Node`	`nextNode()` Returns the next node in the set and advances the position of the `NodeIterator` in the set.
`Node`	`previousNode()` Returns the previous node in the set and moves the position of the `NodeIterator` backwards in the set.

Method Detail

getRoot

Node getRoot()

The root node of the NodeIterator, as specified when it was created.

getWhatToShow

int getWhatToShow()

This attribute determines which node types are presented via the NodeIterator. The available set of constants is defined in the NodeFilter interface. Nodes not accepted by whatToShow will be skipped, but their children may still be considered. Note that this skip takes precedence over the filter, if any.

getFilter

NodeFilter getFilter()

The NodeFilter used to screen nodes.

getExpandEntityReferences

boolean getExpandEntityReferences()

The value of this flag determines whether the children of entity reference nodes are visible to the NodeIterator. If false, these children and their descendants will be rejected. Note that this rejection takes precedence over whatToShow and the filter. Also note that this is currently the only situation where NodeIterators may reject a complete subtree rather than skipping individual nodes.

To produce a view of the document that has entity references expanded and does not expose the entity reference node itself, use the whatToShow flags to hide the entity reference node and set expandEntityReferences to true when creating the NodeIterator. To produce a view of the document that has entity reference nodes but no entity expansion, use the whatToShow flags to show the entity reference node and set expandEntityReferences to false.

nextNode

Node nextNode()
              throws DOMException

Returns the next node in the set and advances the position of the NodeIterator in the set. After a NodeIterator is created, the first call to nextNode() returns the first node in the set.

Returns:: The next Node in the set being iterated over, or null if there are no more members in that set.
Throws:: DOMException - INVALID_STATE_ERR: Raised if this method is called after the detach method was invoked.

previousNode

Node previousNode()
                  throws DOMException

Returns the previous node in the set and moves the position of the NodeIterator backwards in the set.

Returns:: The previous Node in the set being iterated over, or null if there are no more members in that set.
Throws:: DOMException - INVALID_STATE_ERR: Raised if this method is called after the detach method was invoked.

detach

void detach()

Detaches the NodeIterator from the set which it iterated over, releasing any computational resources and placing the NodeIterator in the INVALID state. After detach has been invoked, calls to nextNode or previousNode will raise the exception INVALID_STATE_ERR.