com.eibus.xml.xpath

Class XPathReader

java.lang.Object

com.eibus.xml.xpath.XPathReader

public class XPathReader
extends java.lang.Object

This class provides the methods to select elements in stream based way. This provides a facility to use XPath on a file/URI without actually parsing the complete source XML. With this, we first intialize the XPathReader with the filename or URI and XPath object. After initializing the XPathReader, we can use methods to get the next matched element. The parsing of XML will take place after identifying the exact matching element and it will parse only the next matched content only.
This stream based selection of elements will save memory and increase performance. This will support only forward navigation across matched elements.

The usage methodology of XPathReader is as follows :
Document oDocument = new Document();
String fileName = "BookStore.xml";
XPathMetaInfo oMeta = new XPathMetaInfo();
oMeta.addNamespaceBinding("cordys", "http://schemas.cordys.com/bookstore");
XPath oXPath = new XPath("/cordys:book/chapter/lesson");
XPathReader oXPathReader = XPathReader.getXPathReader(oXPath, oMeta, oDocument, fileName);
//If the reader is to be created from an InputStream object, use :
//XPathReader oXPathReader = XPathReader.getXPathReaderFromStream(oXPath, oXPathMetaInfo, oDocument, inputStream);
oXPathReader.open();
int node = oXPathReader.loadNextNode();
while (nods != 0)
{
// process node
//Call 'getNextMatchInLoadedNode()' for finding any further matching node in the loaded node.
//'getNextMatchInLoadedNode()' can potentially select nodes, if the search pattern
// contains descendant or descendant-or-self axes.
Node.delete(node);
node = oXPathReader.loadNextNode();
}
oXPathReader.close();


Method Summary

Modifier and Type	Method and Description
boolean	close() Closes the XPathReader.
NodeSet	getNextMatch() Deprecated. , please use 'loadNextNode' and 'getNextMatchInLoadedNode'
int	getNextMatchInLoadedNode() Return the next matching node in the loaded NOM tree returned by loadNextNode() method.
int	getNextNode() Deprecated. , please use 'loadNextNode' and 'getNextMatchInLoadedNode'
ResourceOwner	getResourceOwner() Deprecated.
static XPathReader	getXPathReader(XPath xpath, XPathMetaInfo meta, Document doc, java.lang.String uri) Creates the XPathReader instance for URI.
static XPathReader	getXPathReaderFromStream(XPath xpath, XPathMetaInfo meta, Document doc, java.io.InputStream input) Creates the XPathReader instance for the InputStream
int	loadNextNode() Loads the next NOM node from the stream.
boolean	open() Opens the XPathReader for processing.

Methods inherited from class java.lang.Object

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

Method Detail

getResourceOwner

public ResourceOwner getResourceOwner()

Deprecated.

This method is used for internal purposes.

getXPathReader

public static XPathReader getXPathReader(XPath xpath,
                                         XPathMetaInfo meta,
                                         Document doc,
                                         java.lang.String uri)

Creates the XPathReader instance for URI.

Parameters:

xpath - The XPath object for identifying the pattern

meta - The XPath meta information

doc - The NOM Document required for parsing the target/selected XML content

uri - The source xml location

Returns:

The XPathReader instance or null if the input data is invalid.

getXPathReaderFromStream

public static XPathReader getXPathReaderFromStream(XPath xpath,
                                                   XPathMetaInfo meta,
                                                   Document doc,
                                                   java.io.InputStream input)

Creates the XPathReader instance for the InputStream

Parameters:

xpath - The XPath object for identifying the pattern

meta - The XPath meta information

doc - The NOM Document required for parsing the target/selected XML content

inputStream - The InputStream object representing the source xml.

Returns:

The XPathReader instance or null if the input data is invalid.

open

public boolean open()

Opens the XPathReader for processing.

Returns:

True if the reader open is success, otherwise it returns false

getNextMatch

public NodeSet getNextMatch()

Deprecated. , please use 'loadNextNode' and 'getNextMatchInLoadedNode'

Returns the next matched XML content as a nodeset

Returns:

Returns the next matched XML as a NodeSet

getNextNode

public int getNextNode()

Deprecated. , please use 'loadNextNode' and 'getNextMatchInLoadedNode'

Returns the next node of the XPath match The returned node is for consumption only. Consumers should not alter the returned node. Consumers have to duplicate the returned node if they want to persist it

Returns:

Returns the next matched NOM node

close

public boolean close()

Closes the XPathReader.

Returns:

True if the reader close is success, otherwise it returns false

loadNextNode

public int loadNextNode()

Loads the next NOM node from the stream. The loaded node will be an orphan node. The loaded node may contain other node which also matches the pattern.

Returns:

- The loaded NOM node

See Also:

getNextMatchInLoadedNode()

getNextMatchInLoadedNode

public int getNextMatchInLoadedNode()

Return the next matching node in the loaded NOM tree returned by loadNextNode() method.

Returns:

next match NOM node in the node loaded