/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.synapse.config.xml;
import org.apache.axiom.om.OMContainer;
import org.apache.axiom.om.OMDocument;
import org.apache.axiom.om.OMElement;
import org.apache.axiom.om.OMNamespace;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.synapse.SynapseException;
import org.jaxen.JaxenException;
import org.jaxen.XPath;
import java.util.Iterator;
/**
* Holds Axiom utility methods used by Synapse
*/
public class OMElementUtils {
private static final Log log = LogFactory.getLog(OMElementUtils.class);
/**
* Return the namespace with the given prefix, using the given element
* @param prefix the prefix looked up
* @param elem the source element to use
* @return the namespace which maps to the prefix or null
*/
public static String getNameSpaceWithPrefix(String prefix, OMElement elem) {
if (prefix == null || elem == null) {
log.warn("Searching for null NS prefix and/or using null OMElement");
return null;
}
OMElement currentElem = elem;
while (true) {
Iterator iter = currentElem.getAllDeclaredNamespaces();
while (iter.hasNext()) {
OMNamespace ns = (OMNamespace) iter.next();
if (prefix.equals(ns.getPrefix())) {
return ns.getNamespaceURI();
}
}
OMContainer parent = currentElem.getParent();
if (parent != null && parent instanceof OMElement) {
currentElem = (OMElement)parent;
} else {
return null;
}
}
}
/**
* Add the namespace declarations of a given {@link OMElement} to the namespace
* context of an XPath expression. Typically this method is used with an XPath
* expression appearing in an attribute of the given element.
* <p>
* Note that the default namespace is explicitly excluded and not added to the
* namespace context. This implies that XPath expressions
* appearing in Synapse configuration files follow the same rule as in XSL
* stylesheets. Indeed, the XSLT specification defines the namespace context of
* an XPath expression as follows:
* <blockquote>
* the set of namespace declarations are those in scope on the element which has the
* attribute in which the expression occurs; [...] the default namespace
* (as declared by xmlns) is not part of this set
* </blockquote>
*
* @param xpath
* @param elem
* @param log
*/
public static void addNameSpaces(XPath xpath, OMElement elem, Log log) {
OMElement currentElem = elem;
while (currentElem != null) {
Iterator it = currentElem.getAllDeclaredNamespaces();
while (it.hasNext()) {
OMNamespace n = (OMNamespace) it.next();
// Exclude the default namespace as explained in the Javadoc above
if (n != null && !"".equals(n.getPrefix())) {
try {
xpath.addNamespace(n.getPrefix(), n.getNamespaceURI());
} catch (JaxenException je) {
String msg = "Error adding declared name space with prefix : "
+ n.getPrefix() + "and uri : " + n.getNamespaceURI()
+ " to the XPath : " + xpath;
log.error(msg);
throw new SynapseException(msg, je);
}
}
}
OMContainer parent = currentElem.getParent();
//if the parent is a document element or parent is null ,then return
if (parent == null || parent instanceof OMDocument) {
return;
}
if (parent instanceof OMElement) {
currentElem = (OMElement) parent;
}
}
}
}