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javax.xml.xpath

public abstract Class XPathFactory

extends Object
Class Inheritance
Known Direct Subclasses
com.sun.org.apache.xpath.internal.jaxp.XPathFactoryImpl
Imports
com.sun.org.apache.xpath.internal.jaxp.XPathFactoryImpl, jdk.xml.internal.SecuritySupport

An XPathFactory instance can be used to create javax.xml.xpath.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.

Authors
Norman Walsh, Jeff Suttor
Since
1.5

Field Summary

Modifier and TypeField and Description
public static final String
DEFAULT_OBJECT_MODEL_URI

Default Object Model URI.

public static final String
DEFAULT_PROPERTY_NAME

The default property name according to the JAXP spec.

Constructor Summary

AccessConstructor 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.

Method Summary

Modifier and TypeMethod and Description
public abstract boolean

Returns:

State of the named feature.
getFeature(String
Feature name.
name)

Get the state of the named feature.

public String

Returns:

the value of the property.
getProperty(String
the property name
name)

Returns the value of the specified property.

public abstract boolean

Returns:

true if XPathFactory supports objectModel, else false.
isObjectModelSupported(String
Specifies the object model which the returned XPathFactory will understand.
objectModel)

Is specified object model supported by this XPathFactory?

public static XPathFactory

Returns:

A new instance of the XPathFactory builtin system-default implementation.
newDefaultInstance()

Creates a new instance of the XPathFactory builtin system-default implementation.

public static XPathFactory

Returns:

Instance of an XPathFactory.
newInstance()

Get a new XPathFactory instance using the default object model, DEFAULT_OBJECT_MODEL_URI, the W3C DOM.

public static XPathFactory

Returns:

Instance of an XPathFactory.
newInstance(final String
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.
uri)

Obtains a new XPathFactory instance using the specified object model.

public static XPathFactory

Returns:

New instance of a XPathFactory
newInstance(String
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.
uri, String
fully qualified factory class name that provides implementation of javax.xml.xpath.XPathFactory.
factoryClassName, ClassLoader
ClassLoader used to load the factory class. If null current Thread's context classLoader is used to load the factory class.
classLoader)

Obtain a new instance of a XPathFactory from a factory class name.

public abstract XPath

Returns:

New instance of an XPath.
newXPath()

Return a new XPath using the underlying object model determined when the XPathFactory was instantiated.

public abstract void
setFeature(String
Feature name.
name, boolean
Is feature state true or false.
value)

Sets a feature for this XPathFactory.

public void
setProperty(String
the property name
name, String
the value for the property
value)

Sets a property for this XPathFactory.

public abstract void
setXPathFunctionResolver(XPathFunctionResolver
XPath function resolver.
resolver)

Establish a default function resolver.

public abstract void
setXPathVariableResolver(XPathVariableResolver
Variable resolver.
resolver)

Establish a default variable resolver.

Inherited from java.lang.Object:
cloneequalsfinalizegetClasshashCodenotifynotifyAlltoStringwaitwaitwait

Field Detail

DEFAULT_OBJECT_MODEL_URIback to summary
public static final String DEFAULT_OBJECT_MODEL_URI

Default Object Model URI.

DEFAULT_PROPERTY_NAMEback to summary
public static final String DEFAULT_PROPERTY_NAME

The default property name according to the JAXP spec.

Constructor Detail

XPathFactoryback to summary
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.

Method Detail

getFeatureback to summary
public abstract boolean getFeature(String name) throws XPathFactoryConfigurationException

Get the state of the named feature.

Feature names are fully qualified java.net.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.

Parameters
name:String

Feature name.

Returns:boolean

State of the named feature.

Exceptions
XPathFactoryConfigurationException:
if this XPathFactory or the XPaths it creates cannot support this feature.
NullPointerException:
if name is null.
getPropertyback to summary
public String getProperty(String name)

Returns the value of the specified property.

Implementation Specification

The default implementation throws java.lang.UnsupportedOperationException.

Parameters
name:String

the property name

Returns:String

the value of the property.

Exceptions
IllegalArgumentException:
if the property name is not recognized
UnsupportedOperationException:
if the implementation does not support the method
NullPointerException:
if the name is null
Since
18
isObjectModelSupportedback to summary
public abstract boolean isObjectModelSupported(String objectModel)

Is specified object model supported by this XPathFactory?

Parameters
objectModel:String

Specifies the object model which the returned XPathFactory will understand.

Returns:boolean

true if XPathFactory supports objectModel, else false.

Exceptions
NullPointerException:
If objectModel is null.
IllegalArgumentException:
If objectModel.length() == 0.
newDefaultInstanceback to summary
public static XPathFactory newDefaultInstance()

Creates a new instance of the XPathFactory builtin system-default implementation.

Implementation Specification

The XPathFactory builtin system-default implementation is only required to support the default object model, the W3C DOM, but may support additional object models.

Returns:XPathFactory

A new instance of the XPathFactory builtin system-default implementation.

Since
9
newInstanceback to summary
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.

Returns:XPathFactory

Instance of an XPathFactory.

Exceptions
RuntimeException:
When there is a failure in creating an XPathFactory for the default object model.
newInstanceback to summary
public static XPathFactory newInstance(final String uri) throws XPathFactoryConfigurationException

Obtains a new XPathFactory instance using the specified object model. This method uses the JAXP Lookup Mechanism to determine and load the XPathFactory implementation that supports the specified object model.

Tip for Trouble-shooting:

See java.util.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:String

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.

Returns:XPathFactory

Instance of an XPathFactory.

Exceptions
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.
newInstanceback to summary
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.

Tip for Trouble-shooting

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 ....
Parameters
uri:String

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:String

fully qualified factory class name that provides implementation of javax.xml.xpath.XPathFactory.

classLoader:ClassLoader

ClassLoader used to load the factory class. If null current Thread's context classLoader is used to load the factory class.

Returns:XPathFactory

New instance of a XPathFactory

Exceptions
XPathFactoryConfigurationException:
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.
Since
1.6
See Also
newInstance(), newInstance(String uri)
newXPathback to summary
public abstract XPath newXPath()

Return a new XPath using the underlying object model determined when the XPathFactory was instantiated.

Returns:XPath

New instance of an XPath.

setFeatureback to summary
public abstract void setFeature(String name, boolean value) throws XPathFactoryConfigurationException

Sets a feature for this XPathFactory. The feature applies to XPath objects that the XPathFactory creates. It has no impact on XPath objects that are already created.

Feature names are fully qualified java.net.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 javax.xml.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.

Parameters
name:String

Feature name.

value:boolean

Is feature state true or false.

Exceptions
XPathFactoryConfigurationException:
if this XPathFactory or the XPaths it creates cannot support this feature.
NullPointerException:
if name is null.
setPropertyback to summary
public void setProperty(String name, String value)

Sets a property for this XPathFactory. The property applies to XPath objects that the XPathFactory creates. It has no impact on XPath objects that are already created.

A property can either be defined in this XPathFactory, or by the underlying implementation.

Implementation Specification

The default implementation throws java.lang.UnsupportedOperationException.

Parameters
name:String

the property name

value:String

the value for the property

Exceptions
IllegalArgumentException:
if the property name is not recognized, or the value can not be assigned
UnsupportedOperationException:
if the implementation does not support the method
NullPointerException:
if the name is null
Since
18
setXPathFunctionResolverback to summary
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.

Parameters
resolver:XPathFunctionResolver

XPath function resolver.

Exceptions
NullPointerException:
If resolver is null.
setXPathVariableResolverback to summary
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.

Parameters
resolver:XPathVariableResolver

Variable resolver.

Exceptions
NullPointerException:
If resolver is null.