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	/*
	* Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package javax.xml.xpath;

	import com.sun.org.apache.xpath.internal.jaxp.XPathFactoryImpl;
	import jdk.xml.internal.SecuritySupport;

	/**
	* <p>An {@code XPathFactory} instance can be used to create
	* {@link javax.xml.xpath.XPath} objects.</p>
	*
	*<p>See {@link #newInstance(String uri)} for lookup mechanism.</p>
	*
	* <p>The {@link 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 {@link XPathFactory} object at any
	* given moment. Implementations are encouraged to mark methods
	* as <code>synchronized</code> to protect themselves from broken clients.
	*
	* <p>{@link XPathFactory} is not re-entrant. While one of the
	* <code>newInstance</code> methods is being invoked, applications
	* may not attempt to recursively invoke a <code>newInstance</code> method,
	* even from the same thread.
	*
	* @author Norman Walsh
	* @author Jeff Suttor
	*
	* @since 1.5
	*/
	public abstract class XPathFactory {


	/**
	* <p>The default property name according to the JAXP spec.</p>
	*/
	public static final String DEFAULT_PROPERTY_NAME = "javax.xml.xpath.XPathFactory";

	/**
	* <p>Default Object Model URI.</p>
	*/
	public static final String DEFAULT_OBJECT_MODEL_URI = "http://java.sun.com/jaxp/xpath/dom";

	/**
	* <p>Protected constructor as {@link #newInstance()} or {@link #newInstance(String uri)}
	* or {@link #newInstance(String uri, String factoryClassName, ClassLoader classLoader)}
	* should be used to create a new instance of an {@code XPathFactory}.</p>
	*/
	protected XPathFactory() {
	}

	/**
	* Creates a new instance of the {@code XPathFactory} builtin
	* system-default implementation.
	*
	* @implSpec The {@code XPathFactory} builtin
	* system-default implementation is only required to support the
	* {@link #DEFAULT_OBJECT_MODEL_URI default object model}, the
	* {@linkplain org.w3c.dom W3C DOM}, but may support additional
	* object models.
	*
	* @return A new instance of the {@code XPathFactory} builtin
	* system-default implementation.
	*
	* @since 9
	*/
	public static XPathFactory newDefaultInstance() {
	return new XPathFactoryImpl();
	}

	/**
	* <p>Get a new {@code XPathFactory} instance using the default object model,
	* {@link #DEFAULT_OBJECT_MODEL_URI},
	* the W3C DOM.</p>
	*
	* <p>This method is functionally equivalent to:</p>
	* <pre>
	* newInstance(DEFAULT_OBJECT_MODEL_URI)
	* </pre>
	*
	* <p>Since the implementation for the W3C DOM is always available, this method will never fail.</p>
	*
	* @return Instance of an {@code XPathFactory}.
	*
	* @throws RuntimeException When there is a failure in creating an
	* {@code XPathFactory} for the default object model.
	*/
	public static XPathFactory newInstance() {

	try {
	return newInstance(DEFAULT_OBJECT_MODEL_URI);
	} catch (XPathFactoryConfigurationException e) {
	throw new RuntimeException(
	"XPathFactory#newInstance() failed to create an XPathFactory for the default object model: "
	+ DEFAULT_OBJECT_MODEL_URI
	+ " with the XPathFactoryConfigurationException: "
	+ e.getMessage(), e
	);
	}
	}

	/**
	* Obtains a new {@code XPathFactory} instance using the specified object model.
	* This method uses the
	* <a href="../../../module-summary.html#LookupMechanism">JAXP Lookup Mechanism</a>
	* to determine and load the {@code XPathFactory} implementation that supports
	* the specified object model.
	*
	* <p>Tip for Trouble-shooting:
	* <p>See {@link 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:
	* <pre>
	* http\://java.sun.com/jaxp/xpath/dom=org.acme.DomXPathFactory
	* </pre>
	*
	* @param uri Identifies the underlying object model.
	* The specification only defines the URI {@link #DEFAULT_OBJECT_MODEL_URI},
	* <code>http://java.sun.com/jaxp/xpath/dom</code> for the W3C DOM,
	* the org.w3c.dom package, and implementations are free to introduce other URIs for other object models.
	*
	* @return Instance of an {@code XPathFactory}.
	*
	* @throws XPathFactoryConfigurationException If the specified object model
	* is unavailable, or if there is a configuration error.
	* @throws NullPointerException If <code>uri</code> is <code>null</code>.
	* @throws IllegalArgumentException If <code>uri</code> is <code>null</code>
	* or <code>uri.length() == 0</code>.
	*/
	public static XPathFactory newInstance(final String uri)
	throws XPathFactoryConfigurationException {

	if (uri == null) {
	throw new NullPointerException(
	"XPathFactory#newInstance(String uri) cannot be called with uri == null");
	}

	if (uri.length() == 0) {
	throw new IllegalArgumentException(
	"XPathFactory#newInstance(String uri) cannot be called with uri == \"\"");
	}

	ClassLoader classLoader = SecuritySupport.getContextClassLoader();

	if (classLoader == null) {
	//use the current class loader
	classLoader = XPathFactory.class.getClassLoader();
	}

	XPathFactory xpathFactory = new XPathFactoryFinder(classLoader).newFactory(uri);

	if (xpathFactory == null) {
	throw new XPathFactoryConfigurationException(
	"No XPathFactory implementation found for the object model: "
	+ uri);
	}

	return xpathFactory;
	}

	/**
	* <p>Obtain a new instance of a {@code XPathFactory} from a factory class name. {@code 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.</p>
	*
	*
	* <h4>Tip for Trouble-shooting</h4>
	* <p>Setting the <code>jaxp.debug</code> system property will cause
	* this method to print a lot of debug messages
	* to <code>System.err</code> about what it is doing and where it is looking at.</p>
	*
	* <p> If you have problems try:</p>
	* <pre>
	* java -Djaxp.debug=1 YourProgram ....
	* </pre>
	*
	* @param uri Identifies the underlying object model. The specification only defines the URI
	* {@link #DEFAULT_OBJECT_MODEL_URI},<code>http://java.sun.com/jaxp/xpath/dom</code>
	* for the W3C DOM, the org.w3c.dom package, and implementations are free to introduce
	* other URIs for other object models.
	*
	* @param factoryClassName fully qualified factory class name that provides implementation of <code>javax.xml.xpath.XPathFactory</code>.
	*
	* @param classLoader <code>ClassLoader</code> used to load the factory class. If <code>null</code>
	* current <code>Thread</code>'s context classLoader is used to load the factory class.
	*
	*
	* @return New instance of a {@code XPathFactory}
	*
	* @throws XPathFactoryConfigurationException
	* if <code>factoryClassName</code> is <code>null</code>, or
	* the factory class cannot be loaded, instantiated
	* or the factory class does not support the object model specified
	* in the <code>uri</code> parameter.
	*
	* @throws NullPointerException If <code>uri</code> is <code>null</code>.
	* @throws IllegalArgumentException If <code>uri</code> is <code>null</code>
	* or <code>uri.length() == 0</code>.
	*
	* @see #newInstance()
	* @see #newInstance(String uri)
	*
	* @since 1.6
	*/
	public static XPathFactory newInstance(String uri, String factoryClassName, ClassLoader classLoader)
	throws XPathFactoryConfigurationException{
	ClassLoader cl = classLoader;

	if (uri == null) {
	throw new NullPointerException(
	"XPathFactory#newInstance(String uri) cannot be called with uri == null");
	}

	if (uri.length() == 0) {
	throw new IllegalArgumentException(
	"XPathFactory#newInstance(String uri) cannot be called with uri == \"\"");
	}

	if (cl == null) {
	cl = SecuritySupport.getContextClassLoader();
	}

	XPathFactory f = new XPathFactoryFinder(cl).createInstance(factoryClassName);

	if (f == null) {
	throw new XPathFactoryConfigurationException(
	"No XPathFactory implementation found for the object model: "
	+ uri);
	}
	//if this factory supports the given schemalanguage return this factory else thrown exception
	if (f.isObjectModelSupported(uri)) {
	return f;
	} else {
	throw new XPathFactoryConfigurationException("Factory "
	+ factoryClassName + " doesn't support given " + uri
	+ " object model");
	}

	}

	/**
	* <p>Is specified object model supported by this {@code XPathFactory}?</p>
	*
	* @param objectModel Specifies the object model which the returned {@code XPathFactory} will understand.
	*
	* @return <code>true</code> if {@code XPathFactory} supports <code>objectModel</code>, else <code>false</code>.
	*
	* @throws NullPointerException If <code>objectModel</code> is <code>null</code>.
	* @throws IllegalArgumentException If <code>objectModel.length() == 0</code>.
	*/
	public abstract boolean isObjectModelSupported(String objectModel);

	/**
	* <p>Set a feature for this {@code XPathFactory} and
	* <code>XPath</code>s created by this factory.</p>
	*
	* <p>
	* Feature names are fully qualified {@link java.net.URI}s.
	* Implementations may define their own features.
	* An {@link XPathFactoryConfigurationException} is thrown if this
	* {@code XPathFactory} or the <code>XPath</code>s
	* it creates cannot support the feature.
	* It is possible for an {@code XPathFactory} to expose a feature value
	* but be unable to change its state.
	* </p>
	*
	* <p>
	* All implementations are required to support the {@link javax.xml.XMLConstants#FEATURE_SECURE_PROCESSING} feature.
	* When the feature is <code>true</code>, any reference to an external function is an error.
	* Under these conditions, the implementation must not call the {@link XPathFunctionResolver}
	* and must throw an {@link XPathFunctionException}.
	* </p>
	*
	* @param name Feature name.
	* @param value Is feature state <code>true</code> or <code>false</code>.
	*
	* @throws XPathFactoryConfigurationException if this {@code XPathFactory} or the <code>XPath</code>s
	* it creates cannot support this feature.
	* @throws NullPointerException if <code>name</code> is <code>null</code>.
	*/
	public abstract void setFeature(String name, boolean value)
	throws XPathFactoryConfigurationException;

	/**
	* <p>Get the state of the named feature.</p>
	*
	* <p>
	* Feature names are fully qualified {@link java.net.URI}s.
	* Implementations may define their own features.
	* An {@link XPathFactoryConfigurationException} is thrown if this
	* {@code XPathFactory} or the <code>XPath</code>s
	* it creates cannot support the feature.
	* It is possible for an {@code XPathFactory} to expose a feature value
	* but be unable to change its state.
	* </p>
	*
	* @param name Feature name.
	*
	* @return State of the named feature.
	*
	* @throws XPathFactoryConfigurationException if this
	* {@code XPathFactory} or the <code>XPath</code>s
	* it creates cannot support this feature.
	* @throws NullPointerException if <code>name</code> is <code>null</code>.
	*/
	public abstract boolean getFeature(String name)
	throws XPathFactoryConfigurationException;

	/**
	* <p>Establish a default variable resolver.</p>
	*
	* <p>Any <code>XPath</code> objects constructed from this factory will use
	* the specified resolver by default.</p>
	*
	* <p>A <code>NullPointerException</code> is thrown if <code>resolver</code>
	* is <code>null</code>.</p>
	*
	* @param resolver Variable resolver.
	*
	* @throws NullPointerException If <code>resolver</code> is
	* <code>null</code>.
	*/
	public abstract void setXPathVariableResolver(XPathVariableResolver resolver);

	/**
	* <p>Establish a default function resolver.</p>
	*
	* <p>Any <code>XPath</code> objects constructed from this factory will
	* use the specified resolver by default.</p>
	*
	* <p>A <code>NullPointerException</code> is thrown if
	* <code>resolver</code> is <code>null</code>.</p>
	*
	* @param resolver XPath function resolver.
	*
	* @throws NullPointerException If <code>resolver</code> is
	* <code>null</code>.
	*/
	public abstract void setXPathFunctionResolver(XPathFunctionResolver resolver);

	/**
	* <p>Return a new <code>XPath</code> using the underlying object
	* model determined when the {@code XPathFactory} was instantiated.</p>
	*
	* @return New instance of an <code>XPath</code>.
	*/
	public abstract XPath newXPath();
	}

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