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	/*
	* Copyright (c) 2015, 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 com.sun.org.apache.xpath.internal.jaxp;

	import com.sun.org.apache.xpath.internal.objects.XObject;
	import java.util.Objects;
	import javax.xml.transform.TransformerException;
	import javax.xml.xpath.XPathNodes;
	import javax.xml.xpath.XPathEvaluationResult;
	import javax.xml.xpath.XPathEvaluationResult.XPathResultType;
	import org.w3c.dom.Node;
	import org.w3c.dom.NodeList;
	import org.w3c.dom.traversal.NodeIterator;


	/**
	* This is the implementation of XPathEvaluationResult that represents the
	* result of the evaluation of an XPath expression within the context of a
	* particular node.
	*/
	class XPathResultImpl<T> implements XPathEvaluationResult<T> {

	XObject resultObject;
	int resultType;
	Class<T> type;
	XPathResultType mapToType;
	NodeList nodeList = null;
	int currentIndex;
	Node currentNode;

	boolean boolValue = false;
	Node node = null;
	double numValue;
	String strValue;

	/**
	* Construct an XPathEvaluationResult object.
	*
	* @param resultObject internal XPath result object
	* @param type class type
	* @throws TransformerException if there is an error reading the XPath
	* result.
	*/
	public XPathResultImpl(XObject resultObject, Class<T> type)
	throws TransformerException {
	this.resultObject = resultObject;
	resultType = resultObject.getType();
	this.type = type;
	getResult(resultObject);
	}

	/**
	* Return the result type as an enum specified by {@code XPathResultType}
	* @return the result type
	*/
	@Override
	public XPathResultType type() {
	return mapToType;
	}

	/**
	* Returns the value of the result as the type <T> specified for the class.
	*
	* @return The value of the result.
	*/
	@Override
	public T value() {
	Objects.requireNonNull(type);
	try {
	return getValue(resultObject, type);
	} catch (TransformerException ex) {
	throw new RuntimeException(ex);
	}
	}

	/**
	* Read the XObject and set values in accordance with the result type
	* @param resultObject internal XPath result object
	* @throws TransformerException if there is an error reading the XPath
	* result.
	*/
	private void getResult(XObject resultObject) throws TransformerException {
	switch (resultType) {
	case XObject.CLASS_BOOLEAN:
	boolValue = resultObject.bool();
	mapToType = XPathResultType.BOOLEAN;
	break;
	case XObject.CLASS_NUMBER:
	numValue = resultObject.num();
	mapToType = XPathResultType.NUMBER;
	break;
	case XObject.CLASS_STRING:
	strValue = resultObject.str();
	mapToType = XPathResultType.STRING;
	break;
	case XObject.CLASS_NODESET:
	mapToType = XPathResultType.NODESET;
	nodeList = resultObject.nodelist();
	break;
	case XObject.CLASS_RTREEFRAG: //NODE
	mapToType = XPathResultType.NODE;
	NodeIterator ni = resultObject.nodeset();
	//Return the first node, or null
	node = ni.nextNode();
	break;
	}
	}

	/**
	* Read the internal result object and return the value in accordance with
	* the type specified.
	*
	* @param <T> The expected class type.
	* @param resultObject internal XPath result object
	* @param type the class type
	* @return The value of the result, null in case of unexpected type.
	* @throws TransformerException if there is an error reading the XPath
	* result.
	*/
	static <T> T getValue(XObject resultObject, Class<T> type) throws TransformerException {
	Objects.requireNonNull(type);
	if (type.isAssignableFrom(XPathEvaluationResult.class)) {
	return type.cast(new XPathResultImpl<T>(resultObject, type));
	}
	int resultType = classToInternalType(type);
	switch (resultType) {
	case XObject.CLASS_BOOLEAN:
	return type.cast(resultObject.bool());
	case XObject.CLASS_NUMBER:
	if (Double.class.isAssignableFrom(type)) {
	return type.cast(resultObject.num());
	} else if (Integer.class.isAssignableFrom(type)) {
	return type.cast((int)resultObject.num());
	} else if (Long.class.isAssignableFrom(type)) {
	return type.cast((long)resultObject.num());
	}
	/*
	This is to suppress warnings. By the current specification,
	among numeric types, only Double, Integer and Long are supported.
	*/
	break;
	case XObject.CLASS_STRING:
	return type.cast(resultObject.str());
	case XObject.CLASS_NODESET:
	XPathNodes nodeSet = new XPathNodesImpl(resultObject.nodelist(),
	Node.class);
	return type.cast(nodeSet);
	case XObject.CLASS_RTREEFRAG: //NODE
	NodeIterator ni = resultObject.nodeset();
	//Return the first node, or null
	return type.cast(ni.nextNode());
	}

	return null;
	}

	/**
	* Map the specified class type to the internal result type
	*
	* @param <T> The expected class type.
	* @param type the class type
	* @return the internal XObject type.
	*/
	static <T> int classToInternalType(Class<T> type) {
	if (type.isAssignableFrom(Boolean.class)) {
	return XObject.CLASS_BOOLEAN;
	} else if (Number.class.isAssignableFrom(type)) {
	return XObject.CLASS_NUMBER;
	} else if (type.isAssignableFrom(String.class)) {
	return XObject.CLASS_STRING;
	} else if (type.isAssignableFrom(XPathNodes.class)) {
	return XObject.CLASS_NODESET;
	} else if (type.isAssignableFrom(Node.class)) {
	return XObject.CLASS_RTREEFRAG;
	}
	return XObject.CLASS_NULL;
	}
	}

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