XPathTransform.java

/*
 * XAdES4j - A Java library for generation and verification of XAdES signatures.
 * Copyright (C) 2011 Luis Goncalves.
 * 
 * XAdES4j is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 3 of the License, or any later version.
 * 
 * XAdES4j 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 Lesser General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Lesser General Public License along
 * with XAdES4j. If not, see <http://www.gnu.org/licenses/>.
 */
package xades4j.algorithms;

import org.apache.xml.security.transforms.Transforms;

/**
 * The XPath filtering transform.
 * @author Luís
 */
public final class XPathTransform extends XPathTransformBase
{
    private final String xpath;

    /**
     * Creates a new instance of the transform
     * @param xpath the XPath filtering expression
     */
    public XPathTransform(String xpath)
    {
        super(Transforms.TRANSFORM_XPATH);
        if (null == xpath)
        {
            throw new NullPointerException("XPath expression cannot be null");
        }
        this.xpath = xpath;
    }

    public String getXPath()
    {
        return xpath;
    }
    
    /**
     * Registers a namespace and the corresponding prefix to be used when resolving
     * the XPath expression. In the signature, the namespace declaration will be
     * added to the {@code XPath} parameter element of the current transform.
     * 
     * @param prefix the namespace prefix
     * @param namespace the namespace URI
     * 
     * @return the current instance
     */
    public XPathTransform withNamespace(String prefix, String namespace)
    {
        addNamespace(prefix, namespace);
        return this;
    }
}