org.eclipse.jet.xpath
Interface XPathExpression

public interface XPathExpression

Interface to a compiled XPath expression.

Note: Once JET moves to Java 1.5 or later only, this interface will be migrated to javax.xml.xpath.XPathExpression

Method Summary

java.lang.Object	evaluate(java.lang.Object contextObject) Evaluate the expression and return the 'natural' result of the expression.
boolean	evaluateAsBoolean(java.lang.Object contextObject) Evaluate the expression and convert the result to a boolean using the XPath boolean function.
NodeSet	evaluateAsNodeSet(java.lang.Object contextObject) Evaluate the expression and return the result as a Node set.
double	evaluateAsNumber(java.lang.Object contextObject) Evaluate the expression and convert the result to a number using the XPath number function.
java.lang.Object	evaluateAsSingleNode(java.lang.Object contextObject) Evaluate the expression using evaluateAsNodeSet(Object) and then return the first object in the node set.
java.lang.String	evaluateAsString(java.lang.Object contextObject) Evaluate the expression and convert the result to a String using the XPath String function

Method Detail

evaluateAsString

java.lang.String evaluateAsString(java.lang.Object contextObject)
                                  throws XPathRuntimeException

Evaluate the expression and convert the result to a String using the XPath String function

Parameters:

contextObject - the context object for the expression

Returns:

the expression result.

Throws:

XPathRuntimeException - if an evaluation error occures

See Also:

XPathUtil.xpathString(Object)

evaluateAsBoolean

boolean evaluateAsBoolean(java.lang.Object contextObject)
                          throws XPathRuntimeException

Evaluate the expression and convert the result to a boolean using the XPath boolean function.

Parameters:

contextObject - the context object for the expression

Returns:

the expression result.

Throws:

XPathRuntimeException - if an evaluation error occures

See Also:

XPathUtil.xpathBoolean(Object)

evaluateAsNumber

double evaluateAsNumber(java.lang.Object contextObject)
                        throws XPathRuntimeException

Evaluate the expression and convert the result to a number using the XPath number function.

Parameters:

contextObject - the context object for the expression.

Returns:

the expression result

Throws:

XPathRuntimeException - if an evaluation error occures

See Also:

XPathUtil.xpathNumber(Object)

evaluateAsNodeSet

NodeSet evaluateAsNodeSet(java.lang.Object contextObject)
                          throws XPathRuntimeException

Evaluate the expression and return the result as a Node set. If the result cannot be converted to a node set, then an exception is thrown.

Parameters:

contextObject - the context object for the expression.

Returns:

the expression result

Throws:

XPathRuntimeException - if an evaluation error occures

evaluateAsSingleNode

java.lang.Object evaluateAsSingleNode(java.lang.Object contextObject)
                                      throws XPathRuntimeException

Evaluate the expression using evaluateAsNodeSet(Object) and then return the first object in the node set. An exception is thrown if the expression cannot be converted to a node set. If the resulting node set is empty, then null is returned.

Parameters:

contextObject - the context object for the expression.

Returns:

the first element in the node set or null if the node set is empty.

Throws:

XPathRuntimeException - if an evaluation error occures

evaluate

java.lang.Object evaluate(java.lang.Object contextObject)
                          throws XPathRuntimeException

Evaluate the expression and return the 'natural' result of the expression. The result may be any of:

• String
• Boolean
• Number
• NodeSet

Parameters:

contextObject - the context object for the expression.

Returns:

the expression result

Throws:

XPathRuntimeException - if an evaluation error occures