org.apache.xpath.jaxp
Class XPathExpressionImpl

java.lang.Object
  |
  +--org.apache.xpath.jaxp.XPathExpressionImpl

public class XPathExpressionImpl

extends java.lang.Object

implements XPathExpression

The XPathExpression interface encapsulates a (compiled) XPath expression.

Method Summary

java.lang.Object	eval(java.lang.Object item, QName returnType)
java.lang.String	evaluate(InputSource source) Evaluate the compiled XPath expression in the context of the specified InputSource and return the result as a String.
java.lang.Object	evaluate(InputSource source, QName returnType) Evaluate the compiled XPath expression in the context of the specified InputSource and return the result as the specified type.
java.lang.String	evaluate(java.lang.Object item) Evaluate the compiled XPath expression in the specified context and return the result as a String.
java.lang.Object	evaluate(java.lang.Object item, QName returnType) Evaluate the compiled XPath expression in the specified context and return the result as the specified type.
void	setXPath(XPath xpath)

Methods inherited from class java.lang.Object

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

Method Detail

setXPath

public void setXPath(XPath xpath)

eval

public java.lang.Object eval(java.lang.Object item,
                             QName returnType)
                      throws TransformerException

evaluate

public java.lang.Object evaluate(java.lang.Object item,
                                 QName returnType)
                          throws XPathExpressionException

Evaluate the compiled XPath expression in the specified context and return the result as the specified type.

See "Evaluation of XPath Expressions" section of JAXP 1.3 spec for context item evaluation, variable, function and QName resolution and return type conversion.

If returnType is not one of the types defined in XPathConstants, then an IllegalArgumentException is thrown.

If a null value is provided for item, an empty document will be used for the context. If returnType is null, then a NullPointerException is thrown.

Specified by:

evaluate in interface XPathExpression

Parameters:

item - The starting context (node or node list, for example).

returnType - The desired return type.

Returns:

The Object that is the result of evaluating the expression and converting the result to returnType.

Throws:

XPathExpressionException - If the expression cannot be evaluated.

java.lang.IllegalArgumentException - If returnType is not one of the types defined in XPathConstants.

java.lang.NullPointerException - If returnType is null.

evaluate

public java.lang.String evaluate(java.lang.Object item)
                          throws XPathExpressionException

Evaluate the compiled XPath expression in the specified context and return the result as a String.

This method calls evaluate(Object item, QName returnType) with a returnType of XPathConstants.STRING.

See "Evaluation of XPath Expressions" section of JAXP 1.3 spec for context item evaluation, variable, function and QName resolution and return type conversion.

If a null value is provided for item, an empty document will be used for the context.

Specified by:

evaluate in interface XPathExpression

Parameters:

item - The starting context (node or node list, for example).

Returns:

The String that is the result of evaluating the expression and converting the result to a String.

Throws:

XPathExpressionException - If the expression cannot be evaluated.

evaluate

public java.lang.Object evaluate(InputSource source,
                                 QName returnType)
                          throws XPathExpressionException

Evaluate the compiled XPath expression in the context of the specified InputSource and return the result as the specified type.

This method builds a data model for the InputSource and calls evaluate(Object item, QName returnType) on the resulting document object.

See "Evaluation of XPath Expressions" section of JAXP 1.3 spec for context item evaluation, variable, function and QName resolution and return type conversion.

If returnType is not one of the types defined in XPathConstants, then an IllegalArgumentException is thrown.

If source or returnType is null, then a NullPointerException is thrown.

Specified by:

evaluate in interface XPathExpression

Parameters:

source - The InputSource of the document to evaluate over.

returnType - The desired return type.

Returns:

The Object that is the result of evaluating the expression and converting the result to returnType.

Throws:

XPathExpressionException - If the expression cannot be evaluated.

java.lang.IllegalArgumentException - If returnType is not one of the types defined in XPathConstants.

java.lang.NullPointerException - If source or returnType is null.

evaluate

public java.lang.String evaluate(InputSource source)
                          throws XPathExpressionException

Evaluate the compiled XPath expression in the context of the specified InputSource and return the result as a String.

This method calls evaluate(InputSource source, QName returnType) with a returnType of XPathConstants.STRING.

See "Evaluation of XPath Expressions" section of JAXP 1.3 spec for context item evaluation, variable, function and QName resolution and return type conversion.

If source is null, then a NullPointerException is thrown.

Specified by:

evaluate in interface XPathExpression

Parameters:

source - The InputSource of the document to evaluate over.

Returns:

The String that is the result of evaluating the expression and converting the result to a String.

Throws:

XPathExpressionException - If the expression cannot be evaluated.

java.lang.NullPointerException - If source is null.