/*
* 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.cocoon.components.modules.input;
import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.apache.commons.jxpath.JXPathBeanInfo;
import org.apache.commons.jxpath.JXPathContext;
import org.apache.commons.jxpath.JXPathIntrospector;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
/**
* @author <a href="mailto:haul@apache.org">Christian Haul</a>
* @author <a href="mailto:vgritsenko@apache.org">Vadim Gritsenko</a>
* @version $Id$
*/
public class JXPathHelper {
private JXPathHelper() {
// no instances allowed
}
/**
* Configure component. Preprocess list of packages, functions
* and namespaces to add to the JXPath context later.
*
* This method used in both AbstractJXPathModule and JXPathMetaModule
* to configure JXPath.
*
* @param config a <code>Configuration</code> value
* @exception ConfigurationException if an error occurs
*/
public static JXPathHelperConfiguration setup(Configuration config)
throws ConfigurationException {
return new JXPathHelperConfiguration(config);
}
/**
* Actually add global functions and packages as well as those
* listed in the configuration object.
*
* @param context a <code>JXPathContext</code> value
* @param conf a <code>Configuration</code> value holding local
* packages and functions.
*/
private static void setup(JXPathHelperConfiguration setup, JXPathContext context, Configuration conf)
throws ConfigurationException {
// Create local config (if necessary)
JXPathHelperConfiguration local = conf == null ? setup : new JXPathHelperConfiguration(setup, conf);
// Setup context with local config
context.setLenient(setup.isLenient());
context.setFunctions(local.getLibrary());
if (local.getNamespaces() != null) {
for (Iterator i = local.getNamespaces().entrySet().iterator(); i.hasNext();) {
final Map.Entry entry = (Map.Entry) i.next();
context.registerNamespace((String) entry.getKey(), (String) entry.getValue());
}
}
}
/**
* Return the String value of the attribute or element identified in the XPath expression.
* @param name The XPath expression
* @param modeConf The Configuration.
* @param setup The JXPathHelperConfiguration.
* @param contextObj The root Element to search.
* @return The String value of the attribute or element identified.
* @throws ConfigurationException if an Exception occurs.
*/
public static String getAttributeValue(String name,
Configuration modeConf,
JXPathHelperConfiguration setup,
Object contextObj)
throws ConfigurationException {
if (contextObj == null) {
return null;
}
try {
JXPathContext jxContext = JXPathContext.newContext(contextObj);
setup(setup, jxContext, modeConf);
Object obj = jxContext.getValue(name);
if (obj != null) {
return obj.toString();
}
return null;
} catch (Exception e) {
throw new ConfigurationException("Module does not support <" + name + ">" + "attribute.", e);
}
}
/**
* Return the String value of the attribute or the Node found using the XPath expression.
* @param name The XPath expression
* @param modeConf The Configuration.
* @param setup The JXPathHelperConfiguration.
* @param contextObj The root Element to search.
* @return The String value of the attribute or the Element located.
* @throws ConfigurationException if an Exception occurs.
*/
public static Object getAttribute(String name,
Configuration modeConf,
JXPathHelperConfiguration setup,
Object contextObj)
throws ConfigurationException {
if (contextObj == null) {
return null;
}
try {
JXPathContext jxContext = JXPathContext.newContext(contextObj);
setup(setup, jxContext, modeConf);
return jxContext.selectSingleNode(name);
} catch (Exception e) {
throw new ConfigurationException("Module does not support <" + name + ">" + "attribute.", e);
}
}
public static Object[] getAttributeValues(String name,
Configuration modeConf,
JXPathHelperConfiguration setup,
Object contextObj)
throws ConfigurationException {
if (contextObj == null) {
return null;
}
try {
JXPathContext jxContext = JXPathContext.newContext(contextObj);
setup(setup, jxContext, modeConf);
List values = null;
Iterator i = jxContext.iterate(name);
if (i.hasNext()) {
values = new LinkedList();
}
while (i.hasNext()) {
values.add(i.next());
}
Object[] obj = null;
if (values != null) {
obj = values.toArray();
if (obj.length == 0) {
obj = null;
}
}
return obj;
} catch (Exception e) {
throw new ConfigurationException("Module does not support <" + name + ">" + "attribute.", e);
}
}
public static Iterator getAttributeNames(JXPathHelperConfiguration setup, Object contextObj)
throws ConfigurationException {
if (contextObj == null) {
return null;
}
try {
JXPathBeanInfo info = JXPathIntrospector.getBeanInfo(contextObj.getClass());
java.beans.PropertyDescriptor[] properties = info.getPropertyDescriptors();
List names = new LinkedList();
for (int i = 0; i < properties.length; i++) {
names.add(properties[i].getName());
}
return names.listIterator();
} catch (Exception e) {
throw new ConfigurationException("Error retrieving attribute names for class: " + contextObj.getClass(), e);
}
}
}