Class XPathFactory
An XPathFactory
instance can be used to create
XPath
objects.
See newInstance(String uri)
for lookup mechanism.
- Since:
- 1.5
- Version:
- $Revision: 888889 $, $Date: 2009-12-09 19:43:18 +0200 (Wed, 09 Dec 2009) $
- Author:
- Norman Walsh, Jeff Suttor
-
Field Summary
FieldsModifier and TypeFieldDescriptionstatic final java.lang.String
Default Object Model URI.static final java.lang.String
The default property name according to the JAXP spec. -
Constructor Summary
ConstructorsModifierConstructorDescriptionprotected
Protected constructor asnewInstance()
,newInstance(String uri)
ornewInstance(String uri, String factoryClassName, ClassLoader classLoader)
should be used to create a new instance of anXPathFactory
. -
Method Summary
Modifier and TypeMethodDescriptionabstract boolean
getFeature
(java.lang.String name) Get the state of the named feature.abstract boolean
isObjectModelSupported
(java.lang.String objectModel) Is specified object model supported by thisXPathFactory
?static final XPathFactory
Get a newXPathFactory
instance using the default object model,DEFAULT_OBJECT_MODEL_URI
, the W3C DOM.static final XPathFactory
newInstance
(java.lang.String uri) Get a newXPathFactory
instance using the specified object model.static XPathFactory
newInstance
(java.lang.String uri, java.lang.String factoryClassName, java.lang.ClassLoader classLoader) abstract XPath
newXPath()
Return a newXPath
using the underlying object model determined when theXPathFactory
was instantiated.abstract void
setFeature
(java.lang.String name, boolean value) Set a feature for thisXPathFactory
andXPath
s created by this factory.abstract void
Establish a default function resolver.abstract void
Establish a default variable resolver.Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Field Details
-
DEFAULT_PROPERTY_NAME
public static final java.lang.String DEFAULT_PROPERTY_NAMEThe default property name according to the JAXP spec.
- See Also:
-
DEFAULT_OBJECT_MODEL_URI
public static final java.lang.String DEFAULT_OBJECT_MODEL_URIDefault Object Model URI.
- See Also:
-
-
Constructor Details
-
XPathFactory
protected XPathFactory()Protected constructor as
newInstance()
,newInstance(String uri)
ornewInstance(String uri, String factoryClassName, ClassLoader classLoader)
should be used to create a new instance of anXPathFactory
.
-
-
Method Details
-
newInstance
Get a new
XPathFactory
instance using the default object model,DEFAULT_OBJECT_MODEL_URI
, the W3C DOM.This method is functionally equivalent to:
newInstance(DEFAULT_OBJECT_MODEL_URI)
Since the implementation for the W3C DOM is always available, this method will never fail.
- Returns:
- Instance of an
XPathFactory
.
-
newInstance
public static final XPathFactory newInstance(java.lang.String uri) throws XPathFactoryConfigurationException Get a new
XPathFactory
instance using the specified object model.To find a
XPathFactory
object, this method looks the following places in the following order where "the class loader" refers to the context class loader:-
If the system property
DEFAULT_PROPERTY_NAME
+ ":uri" is present, where uri is the parameter to this method, then its value is read as a class name. The method will try to create a new instance of this class by using the class loader, and returns it if it is successfully created. - ${java.home}/lib/jaxp.properties is read and the value associated with the key being the system property above is looked for. If present, the value is processed just like above.
-
The class loader is asked for service provider provider-configuration files matching
javax.xml.xpath.XPathFactory
in the resource directory META-INF/services. See the JAR File Specification for file format and parsing rules. Each potential service provider is required to implement the method:isObjectModelSupported(String objectModel)
-
Platform default
XPathFactory
is located in a platform specific way. There must be a platform default XPathFactory for the W3C DOM, i.e.DEFAULT_OBJECT_MODEL_URI
.
If everything fails, an
XPathFactoryConfigurationException
will be thrown.Tip for Trouble-shooting:
See
Properties.load(java.io.InputStream)
for exactly how a property file is parsed. In particular, colons ':' need to be escaped in a property file, so make sure the URIs are properly escaped in it. For example:http\://java.sun.com/jaxp/xpath/dom=org.acme.DomXPathFactory
- Parameters:
uri
- Identifies the underlying object model. The specification only defines the URIDEFAULT_OBJECT_MODEL_URI
,http://java.sun.com/jaxp/xpath/dom
for the W3C DOM, the org.w3c.dom package, and implementations are free to introduce other URIs for other object models.- Returns:
- Instance of an
XPathFactory
. - Throws:
XPathFactoryConfigurationException
- If the specified object model is unavailable.java.lang.NullPointerException
- Ifuri
isnull
.java.lang.IllegalArgumentException
- Ifuri.length() == 0
.
-
If the system property
-
newInstance
public static XPathFactory newInstance(java.lang.String uri, java.lang.String factoryClassName, java.lang.ClassLoader classLoader) throws XPathFactoryConfigurationException - Returns:
- Instance of an
XPathFactory
. - Throws:
XPathFactoryConfigurationException
- If the specified object model is unavailable.java.lang.NullPointerException
- Ifuri
isnull
.java.lang.IllegalArgumentException
- Ifuri.length() == 0
.
-
isObjectModelSupported
public abstract boolean isObjectModelSupported(java.lang.String objectModel) Is specified object model supported by this
XPathFactory
?- Parameters:
objectModel
- Specifies the object model which the returnedXPathFactory
will understand.- Returns:
true
ifXPathFactory
supportsobjectModel
, elsefalse
.- Throws:
java.lang.NullPointerException
- IfobjectModel
isnull
.java.lang.IllegalArgumentException
- IfobjectModel.length() == 0
.
-
setFeature
public abstract void setFeature(java.lang.String name, boolean value) throws XPathFactoryConfigurationException Set a feature for this
XPathFactory
andXPath
s created by this factory.Feature names are fully qualified
URI
s. Implementations may define their own features. AnXPathFactoryConfigurationException
is thrown if thisXPathFactory
or theXPath
s it creates cannot support the feature. It is possible for anXPathFactory
to expose a feature value but be unable to change its state.All implementations are required to support the
XMLConstants.FEATURE_SECURE_PROCESSING
feature. When the feature istrue
, any reference to an external function is an error. Under these conditions, the implementation must not call theXPathFunctionResolver
and must throw anXPathFunctionException
.- Parameters:
name
- Feature name.value
- Is feature statetrue
orfalse
.- Throws:
XPathFactoryConfigurationException
- if thisXPathFactory
or theXPath
s it creates cannot support this feature.java.lang.NullPointerException
- ifname
isnull
.
-
getFeature
Get the state of the named feature.
Feature names are fully qualified
URI
s. Implementations may define their own features. AnXPathFactoryConfigurationException
is thrown if thisXPathFactory
or theXPath
s it creates cannot support the feature. It is possible for anXPathFactory
to expose a feature value but be unable to change its state.- Parameters:
name
- Feature name.- Returns:
- State of the named feature.
- Throws:
XPathFactoryConfigurationException
- if thisXPathFactory
or theXPath
s it creates cannot support this feature.java.lang.NullPointerException
- ifname
isnull
.
-
setXPathVariableResolver
Establish a default variable resolver.
Any
XPath
objects constructed from this factory will use the specified resolver by default.A
NullPointerException
is thrown ifresolver
isnull
.- Parameters:
resolver
- Variable resolver.- Throws:
java.lang.NullPointerException
- Ifresolver
isnull
.
-
setXPathFunctionResolver
Establish a default function resolver.
Any
XPath
objects constructed from this factory will use the specified resolver by default.A
NullPointerException
is thrown ifresolver
isnull
.- Parameters:
resolver
- XPath function resolver.- Throws:
java.lang.NullPointerException
- Ifresolver
isnull
.
-
newXPath
Return a new
XPath
using the underlying object model determined when theXPathFactory
was instantiated.- Returns:
- New instance of an
XPath
.
-