/**
* 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.activemq.apollo.filter;
import org.apache.xpath.CachedXPathAPI;
import org.apache.xpath.objects.XObject;
import org.w3c.dom.Document;
import org.w3c.dom.traversal.NodeIterator;
import org.xml.sax.InputSource;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Properties;
public class XalanXPathEvaluator implements XPathExpression.XPathEvaluator {
public static final String DOCUMENT_BUILDER_FACTORY_FEATURE = "org.apache.activemq.apollo.documentBuilderFactory.feature";
private final String xpath;
public XalanXPathEvaluator(String xpath) {
this.xpath = xpath;
}
public boolean evaluate(Filterable m) throws FilterException {
String stringBody = m.getBodyAs(String.class);
if (stringBody!=null) {
return evaluate(stringBody);
}
return false;
}
protected boolean evaluate(String text) {
return evaluate(new InputSource(new StringReader(text)));
}
protected boolean evaluate(InputSource inputSource) {
try {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setFeature("http://xml.org/sax/features/external-general-entities", false);
factory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
setupFeatures(factory);
factory.setNamespaceAware(true);
factory.setIgnoringElementContentWhitespace(true);
factory.setIgnoringComments(true);
DocumentBuilder dbuilder = factory.newDocumentBuilder();
Document doc = dbuilder.parse(inputSource);
//An XPath expression could return a true or false value instead of a node.
//eval() is a better way to determine the boolean value of the exp.
//For compliance with legacy behavior where selecting an empty node returns true,
//selectNodeIterator is attempted in case of a failure.
CachedXPathAPI cachedXPathAPI = new CachedXPathAPI();
XObject result = cachedXPathAPI.eval(doc, xpath);
if (result.bool())
return true;
else {
NodeIterator iterator = cachedXPathAPI.selectNodeIterator(doc, xpath);
return (iterator.nextNode() != null);
}
} catch (Throwable e) {
return false;
}
}
protected void setupFeatures(DocumentBuilderFactory factory) {
Properties properties = System.getProperties();
List<String> features = new ArrayList<String>();
for (Map.Entry<Object, Object> prop : properties.entrySet()) {
String key = (String) prop.getKey();
if (key.startsWith(DOCUMENT_BUILDER_FACTORY_FEATURE)) {
String uri = key.split(DOCUMENT_BUILDER_FACTORY_FEATURE + ":")[1];
Boolean value = Boolean.valueOf((String)prop.getValue());
try {
factory.setFeature(uri, value);
features.add("feature " + uri + " value " + value);
} catch (ParserConfigurationException e) {
throw new RuntimeException("DocumentBuilderFactory doesn't support the feature " + uri + " with value " + value + ", due to " + e);
}
}
}
if (features.size() > 0) {
StringBuffer featureString = new StringBuffer();
// just log the configured feature
for (String feature : features) {
if (featureString.length() != 0) {
featureString.append(", ");
}
featureString.append(feature);
}
}
}
}