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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* 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.
*
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package javax.xml.xpath;
import java.util.Objects;
import javax.xml.namespace.QName;
import org.w3c.dom.Node;
/**
* The {@code XPathEvaluationResult} interface represents the result of the
* evaluation of an XPath expression within the context of a particular node.
* The evaluation of an XPath expression can result in various result types as
* defined in XML Path Language (XPath) Version 1.0.
*
* @param <T> the object type returned by the XPath evaluation.
* @see <a href="http://www.w3.org/TR/xpath">XML Path Language (XPath) Version
* 1.0</a>
*
* @since 9
*/
public interface XPathEvaluationResult<T> {
/**
* XPathResultType represents possible return types of an XPath evaluation.
* Provided as an enum type, it allows the use of switch statement. At the
* same time, a mapping is provided between the original QName types in
* {@link XPathConstants} and class types used in the generic methods.
*/
public static enum XPathResultType {
/**
* Any type that represents any of the 5 other types listed below.
* Maps to {@link XPathEvaluationResult}.
*/
ANY(new QName("http://www.w3.org/1999/XSL/Transform", "any"), XPathEvaluationResult.class),
/**
* The XPath 1.0 boolean data type. Maps to Java {@link Boolean}.
*/
BOOLEAN(XPathConstants.BOOLEAN, Boolean.class),
/**
* The XPath 1.0 Number data type. Maps to Java {@link Number}. Of the
* subtypes of Number, only Double, Integer and Long are required.
*/
NUMBER(XPathConstants.NUMBER, Number.class),
/**
* The XPath 1.0 String data type. Maps to Java {@link String}.
*/
STRING(XPathConstants.STRING, String.class),
/**
* The XPath 1.0 NodeSet data type. Maps to {@link org.w3c.dom.NodeList}.
*/
NODESET(XPathConstants.NODESET, XPathNodes.class),
/**
* The XPath 1.0 NodeSet data type. Maps to {@link org.w3c.dom.Node}.
*/
NODE(XPathConstants.NODE, Node.class);
final QName qnameType;
final Class<?> clsType;
XPathResultType(QName qnameType, Class<?> clsType) {
this.qnameType = qnameType;
this.clsType = clsType;
}
/**
* Compares this type to the specified class type.
* @param clsType class type
* @return true if the argument is not null and is a class type that
* matches that this type represents, false otherwise.
*/
private boolean equalsClassType(Class<?> clsType) {
Objects.nonNull(clsType);
if (clsType.isAssignableFrom(this.clsType)) {
return true;
}
return false;
}
/**
* Returns the QName type as specified in {@link XPathConstants} that
* corresponds to the specified class type.
* @param clsType a class type that the enum type supports
* @return the QName type that matches with the specified class type,
* null if there is no match
*/
static public QName getQNameType(Class<?> clsType) {
for (XPathResultType type : XPathResultType.values()) {
if (type.equalsClassType(clsType)) {
return type.qnameType;
}
}
return null;
}
}
/**
* Return the result type as an enum specified by {@code XPathResultType}
* @return the result type
*/
public XPathResultType type();
/**
* Returns the value of the result as the type {@code <T>} specified for the class.
*
* @return The value of the result.
*/
public T value();
}