Class XPathImpl
- java.lang.Object
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- org.apache.xpath.jaxp.XPathImpl
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- All Implemented Interfaces:
javax.xml.xpath.XPath
public class XPathImpl extends java.lang.Object implements javax.xml.xpath.XPath
The XPathImpl class provides implementation for the methods defined in javax.xml.xpath.XPath interface. This provide simple access to the results of an XPath expression.- Version:
- $Revision: 1225280 $
- Author:
- Ramesh Mandava
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description javax.xml.xpath.XPathExpression
compile(java.lang.String expression)
Compile an XPath expression for later evaluation.java.lang.String
evaluate(java.lang.String expression, java.lang.Object item)
Evaluate an XPath expression in the specified context and return the result as aString
.java.lang.Object
evaluate(java.lang.String expression, java.lang.Object item, javax.xml.namespace.QName returnType)
Evaluate anXPath
expression in the specified context and return the result as the specified type.java.lang.String
evaluate(java.lang.String expression, org.xml.sax.InputSource source)
Evaluate an XPath expression in the context of the specifiedInputSource
and return the result as aString
.java.lang.Object
evaluate(java.lang.String expression, org.xml.sax.InputSource source, javax.xml.namespace.QName returnType)
Evaluate an XPath expression in the context of the specifiedInputSource
and return the result as the specified type.javax.xml.namespace.NamespaceContext
getNamespaceContext()
Returns the current namespace context.javax.xml.xpath.XPathFunctionResolver
getXPathFunctionResolver()
Returns the current function resolver.javax.xml.xpath.XPathVariableResolver
getXPathVariableResolver()
Returns the current variable resolver.void
reset()
Reset thisXPath
to its original configuration.void
setNamespaceContext(javax.xml.namespace.NamespaceContext nsContext)
Establishes a namespace context.void
setXPathFunctionResolver(javax.xml.xpath.XPathFunctionResolver resolver)
Establishes a function resolver.void
setXPathVariableResolver(javax.xml.xpath.XPathVariableResolver resolver)
Establishes a variable resolver.
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Method Detail
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setXPathVariableResolver
public void setXPathVariableResolver(javax.xml.xpath.XPathVariableResolver resolver)
Establishes a variable resolver.
- Specified by:
setXPathVariableResolver
in interfacejavax.xml.xpath.XPath
- Parameters:
resolver
- Variable Resolver
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getXPathVariableResolver
public javax.xml.xpath.XPathVariableResolver getXPathVariableResolver()
Returns the current variable resolver.
- Specified by:
getXPathVariableResolver
in interfacejavax.xml.xpath.XPath
- Returns:
- Current variable resolver
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setXPathFunctionResolver
public void setXPathFunctionResolver(javax.xml.xpath.XPathFunctionResolver resolver)
Establishes a function resolver.
- Specified by:
setXPathFunctionResolver
in interfacejavax.xml.xpath.XPath
- Parameters:
resolver
- XPath function resolver
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getXPathFunctionResolver
public javax.xml.xpath.XPathFunctionResolver getXPathFunctionResolver()
Returns the current function resolver.
- Specified by:
getXPathFunctionResolver
in interfacejavax.xml.xpath.XPath
- Returns:
- Current function resolver
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setNamespaceContext
public void setNamespaceContext(javax.xml.namespace.NamespaceContext nsContext)
Establishes a namespace context.
- Specified by:
setNamespaceContext
in interfacejavax.xml.xpath.XPath
- Parameters:
nsContext
- Namespace context to use
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getNamespaceContext
public javax.xml.namespace.NamespaceContext getNamespaceContext()
Returns the current namespace context.
- Specified by:
getNamespaceContext
in interfacejavax.xml.xpath.XPath
- Returns:
- Current Namespace context
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evaluate
public java.lang.Object evaluate(java.lang.String expression, java.lang.Object item, javax.xml.namespace.QName returnType) throws javax.xml.xpath.XPathExpressionException
Evaluate an
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 inXPathConstants
(NUMBER
,STRING
,BOOLEAN
,NODE
orNODESET
) then anIllegalArgumentException
is thrown.If a
null
value is provided foritem
, an empty document will be used for the context. Ifexpression
orreturnType
isnull
, then aNullPointerException
is thrown.- Specified by:
evaluate
in interfacejavax.xml.xpath.XPath
- Parameters:
expression
- The XPath expression.item
- The starting context (node or node list, for example).returnType
- The desired return type.- Returns:
- Result of evaluating an XPath expression as an
Object
ofreturnType
. - Throws:
javax.xml.xpath.XPathExpressionException
- Ifexpression
cannot be evaluated.java.lang.IllegalArgumentException
- IfreturnType
is not one of the types defined inXPathConstants
.java.lang.NullPointerException
- Ifexpression
orreturnType
isnull
.
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evaluate
public java.lang.String evaluate(java.lang.String expression, java.lang.Object item) throws javax.xml.xpath.XPathExpressionException
Evaluate an XPath expression in the specified context and return the result as a
String
.This method calls
evaluate(String expression, Object item, QName returnType)
with areturnType
ofXPathConstants.STRING
.See "Evaluation of XPath Expressions" of JAXP 1.3 spec for context item evaluation, variable, function and QName resolution and return type conversion.
If a
null
value is provided foritem
, an empty document will be used for the context. Ifexpression
isnull
, then aNullPointerException
is thrown.- Specified by:
evaluate
in interfacejavax.xml.xpath.XPath
- Parameters:
expression
- The XPath expression.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 aString
. - Throws:
javax.xml.xpath.XPathExpressionException
- Ifexpression
cannot be evaluated.java.lang.NullPointerException
- Ifexpression
isnull
.
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compile
public javax.xml.xpath.XPathExpression compile(java.lang.String expression) throws javax.xml.xpath.XPathExpressionException
Compile an XPath expression for later evaluation.
If
expression
contains anyXPathFunction
s, they must be available via theXPathFunctionResolver
. AnXPathExpressionException
will be thrown if theXPathFunction
cannot be resovled with theXPathFunctionResolver
.If
expression
isnull
, aNullPointerException
is thrown.- Specified by:
compile
in interfacejavax.xml.xpath.XPath
- Parameters:
expression
- The XPath expression.- Returns:
- Compiled XPath expression.
- Throws:
javax.xml.xpath.XPathExpressionException
- Ifexpression
cannot be compiled.java.lang.NullPointerException
- Ifexpression
isnull
.
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evaluate
public java.lang.Object evaluate(java.lang.String expression, org.xml.sax.InputSource source, javax.xml.namespace.QName returnType) throws javax.xml.xpath.XPathExpressionException
Evaluate an 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 callsevaluate(String expression, 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 inXPathConstants
, then anIllegalArgumentException
is thrown.If
expression
,source
orreturnType
isnull
, then aNullPointerException
is thrown.- Specified by:
evaluate
in interfacejavax.xml.xpath.XPath
- Parameters:
expression
- The XPath expression.source
- The input source of the document to evaluate over.returnType
- The desired return type.- Returns:
- The
Object
that encapsulates the result of evaluating the expression. - Throws:
javax.xml.xpath.XPathExpressionException
- If expression cannot be evaluated.java.lang.IllegalArgumentException
- IfreturnType
is not one of the types defined inXPathConstants
.java.lang.NullPointerException
- Ifexpression
,source
orreturnType
isnull
.
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evaluate
public java.lang.String evaluate(java.lang.String expression, org.xml.sax.InputSource source) throws javax.xml.xpath.XPathExpressionException
Evaluate an XPath expression in the context of the specified
InputSource
and return the result as aString
.This method calls
evaluate(String expression, InputSource source, QName returnType)
with areturnType
ofXPathConstants.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
expression
orsource
isnull
, then aNullPointerException
is thrown.- Specified by:
evaluate
in interfacejavax.xml.xpath.XPath
- Parameters:
expression
- The XPath expression.source
- TheInputSource
of the document to evaluate over.- Returns:
- The
String
that is the result of evaluating the expression and converting the result to aString
. - Throws:
javax.xml.xpath.XPathExpressionException
- If expression cannot be evaluated.java.lang.NullPointerException
- Ifexpression
orsource
isnull
.
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reset
public void reset()
Reset this
XPath
to its original configuration.XPath
is reset to the same state as when it was created withXPathFactory#newXPath()
.reset()
is designed to allow the reuse of existingXPath
s thus saving resources associated with the creation of newXPath
s.The reset
XPath
is not guaranteed to have the sameXPathFunctionResolver
,XPathVariableResolver
orNamespaceContext
Object
s, e.g.Object.equals(Object obj)
. It is guaranteed to have a functionally equalXPathFunctionResolver
,XPathVariableResolver
andNamespaceContext
.- Specified by:
reset
in interfacejavax.xml.xpath.XPath
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