javax.xml.xpath.XPathExpression |
XPathExpression
provides access to compiled XPath expressions.
Evaluation of XPath Expressions. | |
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context | If a request is made to evaluate the expression in the absence of a context item, an empty document node will be used for the context. For the purposes of evaluating XPath expressions, a DocumentFragment is treated like a Document node. |
variables |
If the expression contains a variable reference, its value will be found through the
XPathVariableResolver
.
An
XPathExpressionException
is raised if the variable resolver is undefined or
the resolver returns
null
for the variable.
The value of a variable must be immutable through the course of any single evaluation.
|
functions |
If the expression contains a function reference, the function will be found through the
XPathFunctionResolver
.
An
XPathExpressionException
is raised if the function resolver is undefined or
the function resolver returns
null
for the function.
|
QNames | QNames in the expression are resolved against the XPath namespace context. |
result |
This result of evaluating an expression is converted to an instance of the desired return type.
Valid return types are defined in
XPathConstants
.
Conversion to the return type follows XPath conversion rules.
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Public Methods | |||||||||||
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Evaluate the compiled XPath expression in the specified context and return the result as the specified type. |
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Evaluate the compiled XPath expression in the context of the specified
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Evaluate the compiled XPath expression in the context of the specified
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Evaluate the compiled XPath expression in the specified context and return the result as a
|
Evaluate the compiled XPath expression in the specified context and return the result as the specified type.
See Evaluation of XPath Expressions 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.
item | The starting context (node or node list, for example). |
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returnType | The desired return type. |
Object
that is the result of evaluating the expression and converting the result to
returnType
.
XPathExpressionException | If the expression cannot be evaluated. |
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IllegalArgumentException |
If
returnType
is not one of the types defined in
XPathConstants
.
|
NullPointerException |
If
returnType
is
null
.
|
Evaluate the compiled XPath expression in the context of the specified
InputSource
and return the result as a
String
.
This method calls
evaluate(InputSource, QName)
with a
returnType
of
STRING
.
See Evaluation of XPath Expressions for context item evaluation, variable, function and QName resolution and return type conversion.
If
source
is
null
, then a
NullPointerException
is thrown.
source |
The
InputSource
of the document to evaluate over.
|
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String
that is the result of evaluating the expression and converting the result to a
String
.
XPathExpressionException | If the expression cannot be evaluated. |
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NullPointerException |
If
source
is
null
.
|
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, QName)
on the resulting document object.
See Evaluation of XPath Expressions 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.
source |
The
InputSource
of the document to evaluate over.
|
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returnType | The desired return type. |
Object
that is the result of evaluating the expression and converting the result to
returnType
.
XPathExpressionException | If the expression cannot be evaluated. |
---|---|
IllegalArgumentException |
If
returnType
is not one of the types defined in
XPathConstants
.
|
NullPointerException |
If
source
or
returnType
is
null
.
|
Evaluate the compiled XPath expression in the specified context and return the result as a
String
.
This method calls
evaluate(Object, QName)
with a
returnType
of
STRING
.
See Evaluation of XPath Expressions 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.
item | The starting context (node or node list, for example). |
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String
that is the result of evaluating the expression and converting the result to a
String
.
XPathExpressionException | If the expression cannot be evaluated. |
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