Package org.apache.commons.digester

Class NodeCreateRule

java.lang.Object

org.apache.commons.digester.Rule

org.apache.commons.digester.NodeCreateRule

public class NodeCreateRule
extends Rule

A rule implementation that creates a DOM Node containing the XML at the element that matched the rule. Two concrete types of nodes can be created by this rule:

• the default is to create an Element node. The created element will correspond to the element that matched the rule, containing all XML content underneath that element.
• alternatively, this rule can create nodes of type DocumentFragment, which will contain only the XML content under the element the rule was trigged on.

The created node will be normalized, meaning it will not contain text nodes that only contain white space characters.

The created Node will be pushed on Digester's object stack when done. To use it in the context of another DOM Document, it must be imported first, using the Document method importNode().

Important Note: This is implemented by replacing the SAX ContentHandler in the parser used by Digester, and resetting it when the matched element is closed. As a side effect, rules that would match XML nodes under the element that matches a NodeCreateRule will never be triggered by Digester, which usually is the behavior one would expect.

Note that the current implementation does not set the namespace prefixes in the exported nodes. The (usually more important) namespace URIs are set, of course.

Since:

Digester 1.4

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private class	NodeCreateRule.NodeBuilder	The SAX content handler that does all the actual work of assembling the DOM node tree from the SAX events.

Field Summary

Fields

Modifier and Type	Field	Description
private DocumentBuilder	documentBuilder	The JAXP DocumentBuilder to use.
private int	nodeType	The type of the node that should be created.

Fields inherited from class org.apache.commons.digester.Rule

digester, namespaceURI

Constructor Summary

Constructors

Constructor	Description
NodeCreateRule()	Default constructor.
NodeCreateRule(int nodeType)	Constructor.
NodeCreateRule(int nodeType, DocumentBuilder documentBuilder)	Constructor.
NodeCreateRule(DocumentBuilder documentBuilder)	Constructor.

Method Summary

Modifier and Type	Method	Description
void	begin(String namespaceURI, String name, Attributes attributes)	When this method fires, the digester is told to forward all SAX ContentHandler events to the builder object, resulting in a DOM being built instead of normal digester rule-handling occurring.
void	end()	Pop the Node off the top of the stack.

Methods inherited from class org.apache.commons.digester.Rule

begin, body, body, end, finish, getDigester, getNamespaceURI, setDigester, setNamespaceURI

Methods inherited from class java.lang.Object

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

Field Details

documentBuilder

private DocumentBuilder documentBuilder

The JAXP DocumentBuilder to use.

nodeType

private int nodeType

The type of the node that should be created. Must be one of the constants defined in Node, but currently only Node.ELEMENT_NODE and Node.DOCUMENT_FRAGMENT_NODE are allowed values.

Constructor Details

NodeCreateRule

public NodeCreateRule()
               throws ParserConfigurationException

Default constructor. Creates an instance of this rule that will create a DOM Element.

Throws:

ParserConfigurationException

NodeCreateRule

public NodeCreateRule(DocumentBuilder documentBuilder)

Constructor. Creates an instance of this rule that will create a DOM Element, but lets you specify the JAXP DocumentBuilder that should be used when constructing the node tree.

Parameters:

documentBuilder - the JAXP DocumentBuilder to use

NodeCreateRule

public NodeCreateRule(int nodeType)
               throws ParserConfigurationException

Constructor. Creates an instance of this rule that will create either a DOM Element or a DOM DocumentFragment, depending on the value of the nodeType parameter.

Parameters:

nodeType - the type of node to create, which can be either Node.ELEMENT_NODE or Node.DOCUMENT_FRAGMENT_NODE

Throws:

IllegalArgumentException - if the node type is not supported

ParserConfigurationException

NodeCreateRule

public NodeCreateRule(int nodeType,
 DocumentBuilder documentBuilder)

Constructor. Creates an instance of this rule that will create either a DOM Element or a DOM DocumentFragment, depending on the value of the nodeType parameter. This constructor lets you specify the JAXP DocumentBuilder that should be used when constructing the node tree.

Parameters:

nodeType - the type of node to create, which can be either Node.ELEMENT_NODE or Node.DOCUMENT_FRAGMENT_NODE

documentBuilder - the JAXP DocumentBuilder to use

Throws:

IllegalArgumentException - if the node type is not supported

Method Details

begin

public void begin(String namespaceURI,
 String name,
 Attributes attributes)
           throws Exception

When this method fires, the digester is told to forward all SAX ContentHandler events to the builder object, resulting in a DOM being built instead of normal digester rule-handling occurring. When the end of the current xml element is encountered, the original content handler is restored (expected to be NULL, allowing normal Digester operations to continue).

Overrides:

begin in class Rule

Parameters:

namespaceURI - the namespace URI of the matching element, or an empty string if the parser is not namespace aware or the element has no namespace

name - the local name if the parser is namespace aware, or just the element name otherwise

attributes - The attribute list of this element

Throws:

Exception - indicates a JAXP configuration problem

end

public void end()
         throws Exception

Pop the Node off the top of the stack.

Overrides:

end in class Rule

Throws:

Exception