content: /**
   * 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.filter;
  
  import java.io.IOException;
  import java.lang.reflect.Constructor;
  import java.lang.reflect.InvocationTargetException;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import java.util.Properties;
  import java.util.StringJoiner;
  
  import jakarta.jms.JMSException;
  import javax.xml.XMLConstants;
  import javax.xml.parsers.DocumentBuilder;
  import javax.xml.parsers.DocumentBuilderFactory;
  import javax.xml.parsers.ParserConfigurationException;
  
  import org.apache.activemq.command.Message;
  import org.apache.activemq.util.JMSExceptionSupport;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Used to evaluate an XPath Expression in a JMS selector.
   */
  public final class XPathExpression implements BooleanExpression {
  
      private static final Logger LOG = LoggerFactory.getLogger(XPathExpression.class);
      private static final String EVALUATOR_SYSTEM_PROPERTY = "org.apache.activemq.XPathEvaluatorClassName";
      private static final String DEFAULT_EVALUATOR_CLASS_NAME = "org.apache.activemq.filter.JAXPXPathEvaluator";
      public static final String DOCUMENT_BUILDER_FACTORY_FEATURE = "org.apache.activemq.documentBuilderFactory.feature";
  
      private static final Constructor EVALUATOR_CONSTRUCTOR;
      private static DocumentBuilder builder = null;
  
      static {
          String cn = System.getProperty(EVALUATOR_SYSTEM_PROPERTY, DEFAULT_EVALUATOR_CLASS_NAME);
          Constructor m = null;
          try {
              try {
                  m = getXPathEvaluatorConstructor(cn);
                  DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
                  builderFactory.setNamespaceAware(true);
                  builderFactory.setIgnoringElementContentWhitespace(true);
                  builderFactory.setIgnoringComments(true);
                  try {
                      // set some reasonable defaults
                      builderFactory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, Boolean.TRUE);
                      builderFactory.setFeature("http://xml.org/sax/features/external-general-entities", false);
                      builderFactory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
                      builderFactory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
                  } catch (ParserConfigurationException e) {
                      LOG.warn("Error setting document builder factory feature", e);
                  }
                  // setup the feature from the system property
                  setupFeatures(builderFactory);
                  builder = builderFactory.newDocumentBuilder();
              } catch (Throwable e) {
                  LOG.warn("Invalid " + XPathEvaluator.class.getName() + " implementation: " + cn + ", reason: " + e, e);
                  cn = DEFAULT_EVALUATOR_CLASS_NAME;
                  try {
                      m = getXPathEvaluatorConstructor(cn);
                  } catch (Throwable e2) {
                      LOG.error("Default XPath evaluator could not be loaded", e);
                  }
              }
          } finally {
              EVALUATOR_CONSTRUCTOR = m;
          }
      }
  
      private final String xpath;
      private final XPathEvaluator evaluator;
  
      public static interface XPathEvaluator {
          boolean evaluate(Message message) throws JMSException;
      }
  
      XPathExpression(String xpath) {
          this.xpath = xpath;
          this.evaluator = createEvaluator(xpath);
      }
  
      private static Constructor getXPathEvaluatorConstructor(String cn) throws ClassNotFoundException, SecurityException, NoSuchMethodException {
          Class c = XPathExpression.class.getClassLoader().loadClass(cn);
          if (!XPathEvaluator.class.isAssignableFrom(c)) {
              throw new ClassCastException("" + c + " is not an instance of " + XPathEvaluator.class);
          }
          return c.getConstructor(new Class[] {String.class, DocumentBuilder.class});
      }
  
      protected static 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) {
                      LOG.warn("DocumentBuilderFactory doesn't support the feature {} with value {}, due to {}.", new Object[]{uri, value, e});
                  }
              }
          }
  
          if (LOG.isTraceEnabled() && !features.isEmpty()) {
              StringJoiner featureString = new StringJoiner(", ");
              // just log the configured feature
              for (String feature : features) {
                  featureString.add(feature);
              }
              LOG.trace("Configured features {}", featureString);
          }
  
      }
  
      private XPathEvaluator createEvaluator(String xpath2) {
          try {
              return (XPathEvaluator)EVALUATOR_CONSTRUCTOR.newInstance(new Object[] {xpath, builder});
          } catch (InvocationTargetException e) {
              Throwable cause = e.getCause();
              if (cause instanceof RuntimeException) {
                  throw (RuntimeException)cause;
              }
              throw new RuntimeException("Invalid XPath Expression: " + xpath + " reason: " + e.getMessage(), e);
          } catch (Throwable e) {
              throw new RuntimeException("Invalid XPath Expression: " + xpath + " reason: " + e.getMessage(), e);
          }
      }
  
      public Object evaluate(MessageEvaluationContext message) throws JMSException {
          try {
              if (message.isDropped()) {
                  return null;
              }
              return evaluator.evaluate(message.getMessage()) ? Boolean.TRUE : Boolean.FALSE;
          } catch (IOException e) {
              throw JMSExceptionSupport.create(e);
          }
  
      }
  
      public String toString() {
          return "XPATH " + ConstantExpression.encodeString(xpath);
      }
  
      /**
       * @param message
       * @return true if the expression evaluates to Boolean.TRUE.
       * @throws JMSException
       */
      public boolean matches(MessageEvaluationContext message) throws JMSException {
          Object object = evaluate(message);
          return object != null && object == Boolean.TRUE;
      }
  
  }
  