public abstract class XPathFactory extends Object
An XPathFactory instance can be used to create
XPath objects.
See newInstance(String uri) for lookup mechanism.
The XPathFactory class is not thread-safe. In other words,
it is the application's responsibility to ensure that at most
one thread is using a XPathFactory object at any
given moment. Implementations are encouraged to mark methods
as synchronized to protect themselves from broken clients.
XPathFactory is not re-entrant. While one of the
newInstance methods is being invoked, applications
may not attempt to recursively invoke a newInstance method,
even from the same thread.
| Modifier and Type | Field and Description |
|---|---|
static String |
DEFAULT_OBJECT_MODEL_URI
Default Object Model URI.
|
static String |
DEFAULT_PROPERTY_NAME
The default property name according to the JAXP spec.
|
| Modifier | Constructor and Description |
|---|---|
protected |
XPathFactory()
Protected constructor as
newInstance() or newInstance(String uri)
or newInstance(String uri, String factoryClassName, ClassLoader classLoader)
should be used to create a new instance of an XPathFactory. |
| Modifier and Type | Method and Description |
|---|---|
abstract boolean |
getFeature(String name)
Get the state of the named feature.
|
abstract boolean |
isObjectModelSupported(String objectModel)
Is specified object model supported by this
XPathFactory? |
static XPathFactory |
newInstance()
Get a new
XPathFactory instance using the default object model,
DEFAULT_OBJECT_MODEL_URI,
the W3C DOM. |
static XPathFactory |
newInstance(String uri)
Get a new
XPathFactory instance using the specified object model. |
static XPathFactory |
newInstance(String uri,
String factoryClassName,
ClassLoader classLoader)
Obtain a new instance of a
XPathFactory from a factory class name. |
abstract XPath |
newXPath()
Return a new
XPath using the underlying object
model determined when the XPathFactory was instantiated. |
abstract void |
setFeature(String name,
boolean value)
Set a feature for this
XPathFactory and
XPaths created by this factory. |
abstract void |
setXPathFunctionResolver(XPathFunctionResolver resolver)
Establish a default function resolver.
|
abstract void |
setXPathVariableResolver(XPathVariableResolver resolver)
Establish a default variable resolver.
|
public static final String DEFAULT_PROPERTY_NAME
The default property name according to the JAXP spec.
public static final String DEFAULT_OBJECT_MODEL_URI
Default Object Model URI.
protected XPathFactory()
Protected constructor as newInstance() or newInstance(String uri)
or newInstance(String uri, String factoryClassName, ClassLoader classLoader)
should be used to create a new instance of an XPathFactory.
public static XPathFactory 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.
XPathFactory.RuntimeException - When there is a failure in creating an
XPathFactory for the default object model.public static XPathFactory newInstance(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:
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.
ServiceLoader class, to attempt to locate and load an
implementation of the service using the default loading mechanism:
the service-provider loading facility will use the current thread's context class loader
to attempt to load the service. If the context class
loader is null, the system class loader will be used.
isObjectModelSupported(String objectModel).
The first service provider found that supports the specified object
model is returned.
ServiceConfigurationError an
XPathFactoryConfigurationException will be thrown.
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
uri - Identifies the underlying object model.
The specification only defines the URI DEFAULT_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.XPathFactory.XPathFactoryConfigurationException - If the specified object model
is unavailable, or if there is a configuration error.NullPointerException - If uri is null.IllegalArgumentException - If uri is null
or uri.length() == 0.public static XPathFactory newInstance(String uri, String factoryClassName, ClassLoader classLoader) throws XPathFactoryConfigurationException
Obtain a new instance of a XPathFactory from a factory class name. XPathFactory
is returned if specified factory class supports the specified object model.
This function is useful when there are multiple providers in the classpath.
It gives more control to the application as it can specify which provider
should be loaded.
Setting the jaxp.debug system property will cause
this method to print a lot of debug messages
to System.err about what it is doing and where it is looking at.
If you have problems try:
java -Djaxp.debug=1 YourProgram ....
uri - Identifies the underlying object model. The specification only defines the URI
DEFAULT_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.factoryClassName - fully qualified factory class name that provides implementation of javax.xml.xpath.XPathFactory.classLoader - ClassLoader used to load the factory class. If null
current Thread's context classLoader is used to load the factory class.XPathFactoryXPathFactoryConfigurationException - if factoryClassName is null, or
the factory class cannot be loaded, instantiated
or the factory class does not support the object model specified
in the uri parameter.NullPointerException - If uri is null.IllegalArgumentException - If uri is null
or uri.length() == 0.newInstance(),
newInstance(String uri)public abstract boolean isObjectModelSupported(String objectModel)
Is specified object model supported by this XPathFactory?
objectModel - Specifies the object model which the returned XPathFactory will understand.true if XPathFactory supports objectModel, else false.NullPointerException - If objectModel is null.IllegalArgumentException - If objectModel.length() == 0.public abstract void setFeature(String name, boolean value) throws XPathFactoryConfigurationException
Set a feature for this XPathFactory and
XPaths created by this factory.
Feature names are fully qualified URIs.
Implementations may define their own features.
An XPathFactoryConfigurationException is thrown if this
XPathFactory or the XPaths
it creates cannot support the feature.
It is possible for an XPathFactory 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 is true, any reference to an external function is an error.
Under these conditions, the implementation must not call the XPathFunctionResolver
and must throw an XPathFunctionException.
name - Feature name.value - Is feature state true or false.XPathFactoryConfigurationException - if this XPathFactory or the XPaths
it creates cannot support this feature.NullPointerException - if name is null.public abstract boolean getFeature(String name) throws XPathFactoryConfigurationException
Get the state of the named feature.
Feature names are fully qualified URIs.
Implementations may define their own features.
An XPathFactoryConfigurationException is thrown if this
XPathFactory or the XPaths
it creates cannot support the feature.
It is possible for an XPathFactory to expose a feature value
but be unable to change its state.
name - Feature name.XPathFactoryConfigurationException - if this
XPathFactory or the XPaths
it creates cannot support this feature.NullPointerException - if name is null.public abstract void setXPathVariableResolver(XPathVariableResolver resolver)
Establish a default variable resolver.
Any XPath objects constructed from this factory will use
the specified resolver by default.
A NullPointerException is thrown if resolver
is null.
resolver - Variable resolver.NullPointerException - If resolver is
null.public abstract void setXPathFunctionResolver(XPathFunctionResolver resolver)
Establish a default function resolver.
Any XPath objects constructed from this factory will
use the specified resolver by default.
A NullPointerException is thrown if
resolver is null.
resolver - XPath function resolver.NullPointerException - If resolver is
null.public abstract XPath newXPath()
Return a new XPath using the underlying object
model determined when the XPathFactory was instantiated.
XPath. Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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