merge.java

一个完整的XACML工程,学习XACML技术的好例子!

/*
 * Merge.java
 *
 * Created on 04 November 2006, 18:55
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */

package uk.ac.kent.dpa.custom.authz.util;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.*;
import javax.xml.parsers.*;
import java.util.*;

/**
 *
 * @author ls97
 */
public class Merge {
    
    /** Creates a new instance of Merge */
    public Merge() {
    }
    
    public Element merge(Element e1, Element e2) throws AuthzException {
        if (e1==null) return e2;
        if (e2==null) return e1;
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setValidating(false);
        Document doc = null;
        try {
            doc = factory.newDocumentBuilder().newDocument();
        } catch (ParserConfigurationException pe) {
            throw new AuthzException("XML parser error:"+pe);
        }
        Element request = doc.createElement("Request");
        request.setAttribute("xmlns","urn:oasis:names:tc:xacml:1.0:context");
        request.setAttribute("xmlns:xsi","http://www.w3.org/2001/XMLSchema-instance");
        request.setAttribute("xmlns:permis","http://issrg.cs.kent.ac.uk");
        Element subject = doc.createElement("Subject");
        Element resource = doc.createElement("Resource");
        Element action = doc.createElement("Action");
        Element environment = doc.createElement("Environment");
        NodeList list1 = e1.getChildNodes();
        NodeList list2 = e2.getChildNodes();
        this.merge(subject,list1,doc);
        this.merge(subject,list2,doc);
        this.merge(resource,list1,doc);
        this.merge(resource,list2,doc);
        this.merge(action,list1,doc);
        this.merge(action,list2,doc);
        this.merge(environment,list1,doc);
        this.merge(environment,list2,doc);
        request.appendChild(subject);
        request.appendChild(resource);
        request.appendChild(action);
        request.appendChild(environment);
        return request;
    }
    
    private void merge(Element result, NodeList source, Document doc) {
        for (int i=0; i<source.getLength(); i++) {
            Node node = source.item(i);
            if (Text.class.isAssignableFrom(node.getClass())) continue;
            if (node.getNodeName().equals(result.getNodeName())) {
                NodeList attrs = node.getChildNodes();
                for (int j=0; j<attrs.getLength(); j++) {
                    Node attr = attrs.item(j);
                    if (Text.class.isAssignableFrom(attr.getClass())) continue;
                    String id = ((Element)attr).getAttribute("AttributeId");
                    String type = ((Element)attr).getAttribute("DataType");
                    Element attrEle = doc.createElement(attr.getNodeName());
                    attrEle.setAttribute("AttributeId",id);
                    attrEle.setAttribute("DataType",type);
                    NodeList values = attr.getChildNodes();
                    for (int k=0; k<values.getLength(); k++) {
                        Node value = values.item(k);
                        if (Text.class.isAssignableFrom(value.getClass())) continue;
                        Element valEle = doc.createElement(value.getNodeName());
                        NodeList texts = value.getChildNodes();
                        for (int l=0; l<texts.getLength(); l++) {
                            Node text = texts.item(l);
                            Text t = (Text)text;
                            String str = t.getNodeValue();
                            Text txt = doc.createTextNode(str);
                            valEle.appendChild(txt);
                        }
                        attrEle.appendChild(valEle);
                    }
                    result.appendChild(attrEle);
                }
            }
        }
    }
}