/*
 * Copyright 2005 Sun Microsystems, Inc.  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.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */
/*
 * $Id: DOMXPathTransform.java,v 1.16 2005/05/12 19:28:35 mullan Exp $
 */
package org.jcp.xml.dsig.internal.dom;

import javax.xml.crypto.*;
import javax.xml.crypto.dsig.*;
import javax.xml.crypto.dsig.spec.TransformParameterSpec;
import javax.xml.crypto.dsig.spec.XPathFilterParameterSpec;
import java.security.InvalidAlgorithmParameterException;
import java.util.Iterator;
import java.util.Map;
import java.util.HashMap;
import org.w3c.dom.Attr;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;

/**
 * DOM-based implementation of XPath Filtering Transform.
 * (Uses Apache XML-Sec Transform implementation)
 *
 * @author Sean Mullan
 */
public final class DOMXPathTransform extends ApacheTransform {

    public void init(TransformParameterSpec params)
        throws InvalidAlgorithmParameterException {
        if (params == null) {
            throw new InvalidAlgorithmParameterException("params are required");
        } else if (!(params instanceof XPathFilterParameterSpec)) {
            throw new InvalidAlgorithmParameterException
                ("params must be of type XPathFilterParameterSpec");
        }
        this.params = params;
    }

    public void init(XMLStructure parent, XMLCryptoContext context)
        throws InvalidAlgorithmParameterException {

        super.init(parent, context);
        unmarshalParams(DOMUtils.getFirstChildElement(transformElem));
    }

    private void unmarshalParams(Element paramsElem) {
        String xPath = paramsElem.getFirstChild().getNodeValue();
        // create a Map of namespace prefixes
        NamedNodeMap attributes = paramsElem.getAttributes();
        if (attributes != null) {
            int length = attributes.getLength();
            Map namespaceMap = new HashMap(length);
            for (int i = 0; i < length; i++) {
                Attr attr = (Attr) attributes.item(i);
                String prefix = attr.getPrefix();
                if (prefix != null && prefix.equals("xmlns")) {
                    namespaceMap.put(attr.getLocalName(), attr.getValue());
                }
            }
            this.params = new XPathFilterParameterSpec(xPath, namespaceMap);
        } else {
            this.params = new XPathFilterParameterSpec(xPath);
        }
    }

    public void marshalParams(XMLStructure parent, XMLCryptoContext context)
        throws MarshalException {

        super.marshalParams(parent, context);
        XPathFilterParameterSpec xp =
            (XPathFilterParameterSpec) getParameterSpec();
        Element xpathElem = DOMUtils.createElement
            (ownerDoc, "XPath", XMLSignature.XMLNS,
             DOMUtils.getSignaturePrefix(context));
        xpathElem.appendChild(ownerDoc.createTextNode(xp.getXPath()));

        // add namespace attributes, if necessary
        Iterator i = xp.getNamespaceMap().entrySet().iterator();
        while (i.hasNext()) {
            Map.Entry entry = (Map.Entry) i.next();
            xpathElem.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns:"
                + (String) entry.getKey(), (String) entry.getValue());
        }

        transformElem.appendChild(xpathElem);
    }
}