/*
* Helper method that parses a set of Attribute types. The Subject,
* Action and Environment sections all look like this.
*/
private static List parseAttributes(Node root) throws ParsingException {
List set = new ArrayList();
// the Environment section is just a list of Attributes
NodeList nodes = root.getChildNodes();
for (int i = 0; i < nodes.getLength(); i++) {
Node node = nodes.item(i);
if (SunxacmlUtil.getNodeName(node).equals("Attribute"))
set.add(BasicAttribute.getInstance(node));
}
return set;
}
/**
* Create a new <code>RequestCtx</code> by parsing a node. This node should be created by
* schema-verified parsing of an <code>XML</code> document.
*
* @param root the node to parse for the <code>RequestCtx</code>
* @return a new <code>RequestCtx</code> constructed by parsing
* @throws ParsingException if the DOM node is invalid
*/
public static RequestCtx getInstance(Node root) throws ParsingException {
List newSubjects = new ArrayList();
List newResource = null;
List newAction = null;
List newEnvironment = null;
// First check to be sure the node passed is indeed a Request node.
String tagName = SunxacmlUtil.getNodeName(root);
if (!tagName.equals("Request")) {
throw new ParsingException(
"Request cannot be constructed using " + "type: " + SunxacmlUtil.getNodeName(root));
}
// Now go through its child nodes, finding Subject,
// Resource, Action, and Environment data
NodeList children = root.getChildNodes();
for (int i = 0; i < children.getLength(); i++) {
Node node = children.item(i);
String tag = SunxacmlUtil.getNodeName(node);
if (tag.equals("Subject")) {
// see if there is a category
Node catNode = node.getAttributes().getNamedItem("SubjectCategory");
URI category = null;
if (catNode != null) {
try {
category = new URI(catNode.getNodeValue());
} catch (Exception e) {
throw new ParsingException("Invalid Category URI", e);
}
}
// now we get the attributes
List attributes = parseAttributes(node);
// finally, add the list to the set of subject attributes
newSubjects.add(new Subject(category, attributes));
} else if (tag.equals("Resource")) {
// For now, this code doesn't parse the content, since it's
// a set of anys with a set of anyAttributes, and therefore
// no useful data can be gleaned from it anyway. The theory
// here is that it's only useful in the instance doc, so
// we won't bother parse it, but we may still want to go
// back and provide some support at some point...
newResource = parseAttributes(node);
} else if (tag.equals("Action")) {
newAction = parseAttributes(node);
} else if (tag.equals("Environment")) {
newEnvironment = parseAttributes(node);
}
}
// if we didn't have an environment section, the only optional section
// of the four, then create a new empty set for it
if (newEnvironment == null) newEnvironment = new ArrayList();
// Now create and return the RequestCtx from the information
// gathered
return new BasicRequestCtx(newSubjects, newResource, newAction, newEnvironment, root);
}
