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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * 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

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 */

/*

 * $Id: XPathType.java,v 1.4 2005/05/10 16:40:17 mullan Exp $

 */

package javax.xml.crypto.dsig.spec;

import java.util.Collections;

import java.util.HashMap;

import java.util.Map;

/**

 * The XML Schema Definition of the <code>XPath</code> element as defined in the

 * <a href="http://www.w3.org/TR/xmldsig-filter2">

 * W3C Recommendation for XML-Signature XPath Filter 2.0</a>:

 * <pre><code>

 * <schema xmlns="http://www.w3.org/2001/XMLSchema"

 *         xmlns:xf="http://www.w3.org/2002/06/xmldsig-filter2"

 *         targetNamespace="http://www.w3.org/2002/06/xmldsig-filter2"

 *         version="0.1" elementFormDefault="qualified">

 *

 * <element name="XPath"

 *          type="xf:XPathType"/>

 *

 * <complexType name="XPathType">

 *   <simpleContent>

 *     <extension base="string">

 *       <attribute name="Filter">

 *         <simpleType>

 *           <restriction base="string">

 *             <enumeration value="intersect"/>

 *             <enumeration value="subtract"/>

 *             <enumeration value="union"/>

 *           </restriction>

 *         </simpleType>

 *       </attribute>

 *     </extension>

 *   </simpleContent>

 * </complexType>

 * </code></pre>

 *

 * @author Sean Mullan

 * @author JSR 105 Expert Group

 * @since 1.6

 * @see XPathFilter2ParameterSpec

 */

public class XPathType {

    /**

     * Represents the filter set operation.

     */

    public static class Filter {

        private final String operation;

        private Filter(String operation) {

            this.operation = operation;

        }

        /**

         * Returns the string form of the operation.

         *

         * @return the string form of the operation

         */

        public String toString() {

            return operation;

        }

        /**

         * The intersect filter operation.

         */

        public static final Filter INTERSECT = new Filter("intersect");

        /**

         * The subtract filter operation.

         */

        public static final Filter SUBTRACT = new Filter("subtract");

        /**

         * The union filter operation.

         */

        public static final Filter UNION = new Filter("union");

    }

    private final String expression;

    private final Filter filter;

    /**

     * Creates an <code>XPathType</code> instance with the specified XPath

     * expression and filter.

     *

     * @param expression the XPath expression to be evaluated

     * @param filter the filter operation ({@link Filter#INTERSECT},

     *    {@link Filter#SUBTRACT}, or {@link Filter#UNION})

     * @throws NullPointerException if <code>expression</code> or

     *    <code>filter</code> is <code>null</code>

     */

    public XPathType(String expression, Filter filter) {

        if (expression == null) {

            throw new NullPointerException("expression cannot be null");

        }

        if (filter == null) {

            throw new NullPointerException("filter cannot be null");

        }

        this.expression = expression;

        this.filter = filter;

        this.nsMap = Collections.emptyMap();

    }

    /**

     * Creates an <code>XPathType</code> instance with the specified XPath

     * expression, filter, and namespace map. The map is copied to protect

     * against subsequent modification.

     *

     * @param expression the XPath expression to be evaluated

     * @param filter the filter operation ({@link Filter#INTERSECT},

     *    {@link Filter#SUBTRACT}, or {@link Filter#UNION})

     * @param namespaceMap the map of namespace prefixes. Each key is a

     *    namespace prefix <code>String</code> that maps to a corresponding

     *    namespace URI <code>String</code>.

     * @throws NullPointerException if <code>expression</code>,

     *    <code>filter</code> or <code>namespaceMap</code> are

     *    <code>null</code>

     * @throws ClassCastException if any of the map's keys or entries are

     *    not of type <code>String</code>

     */

        if (namespaceMap == null) {

            throw new NullPointerException("namespaceMap cannot be null");

        }

    }

    /**

     * Returns the XPath expression to be evaluated.

     *

     * @return the XPath expression to be evaluated

     */

    public String getExpression() {

        return expression;

    }

    /**

     * Returns the filter operation.

     *

     * @return the filter operation

     */

    public Filter getFilter() {

        return filter;

    }

    /**

     * Returns a map of namespace prefixes. Each key is a namespace prefix

     * <code>String</code> that maps to a corresponding namespace URI

     * <code>String</code>.

     * <p>

     * This implementation returns an {@link Collections#unmodifiableMap

     * unmodifiable map}.

     *

     * @return a <code>Map</code> of namespace prefixes to namespace URIs

     *    (may be empty, but never <code>null</code>)

     */

        return nsMap;

    }

}