Module org.eclipse.persistence.sdo

Package org.eclipse.persistence.sdo.helper.extension

Class XPathHelper

java.lang.Object

org.eclipse.persistence.sdo.helper.extension.XPathHelper

public class XPathHelper
extends Object

This singleton provides support for querying DataObjects via xpath expression where the result is a List containing one or more simple types or DataObjects.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	XPathHelper.QueryPart	A QueryPart knows the name of the property to be queried against on a given DataObject, as well as the value to be used in the comparison.

Constructor Summary

Constructors

Constructor	Description
XPathHelper()

Method Summary

Modifier and Type	Method	Description
protected List	addResultsToList(Object obj, List results)	Convenience method that will add the provided object to the 'results' list if the object is non-null.
List	evaluate(String expression, DataObject dataObject)	Evaluate an XPath expression in the specified context and return a List containing any types or DataObjects that match the search criteria.
static XPathHelper	getInstance()	Returns the one and only instance of this singleton.
protected String	getPathWithAtRemoved(String expression)	Convenience method that strips off '@' portion, if one exists.
protected String	getPathWithPrefixRemoved(String expression)	Convenience method that strips off 'ns0:' portion, if one exists.
XPathExpression	prepareExpression(String expression)	Create and return an XPathExpression, using the provided string to create the expression.
protected boolean	shouldCallXPathEngine(String expression)	Convenience method for determining if XPathEngine should be called, i.e.

Methods inherited from class java.lang.Object

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

Constructor Details

XPathHelper

public XPathHelper()

Method Details

getInstance

public static XPathHelper getInstance()

Returns the one and only instance of this singleton.

prepareExpression

public XPathExpression prepareExpression(String expression)

Create and return an XPathExpression, using the provided string to create the expression.

Parameters:

expression -

Returns:

evaluate

public List evaluate(String expression,
 DataObject dataObject)

Evaluate an XPath expression in the specified context and return a List containing any types or DataObjects that match the search criteria.

Parameters:

expression -

dataObject -

Returns:

List containing zero or more entries

addResultsToList

protected List addResultsToList(Object obj,
 List results)

Convenience method that will add the provided object to the 'results' list if the object is non-null. If the object represents a list, each non-null entry will be added to the results list.

Parameters:

obj -

results -

Returns:

getPathWithAtRemoved

protected String getPathWithAtRemoved(String expression)

Convenience method that strips off '@' portion, if one exists.

Parameters:

expression -

Returns:

getPathWithPrefixRemoved

protected String getPathWithPrefixRemoved(String expression)

Convenience method that strips off 'ns0:' portion, if one exists.

Parameters:

expression -

Returns:

shouldCallXPathEngine

protected boolean shouldCallXPathEngine(String expression)

Convenience method for determining if XPathEngine should be called, i.e. the XPath expression contains functionality not yet supported.

Parameters:

expression -

Returns: