restconf/restconf-nb-bierman02/src/main/java/org/opendaylight/netconf/sal/streams/listeners/AbstractQueryParams.java

   1 /*
   2  * Copyright (c) 2016 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.netconf.sal.streams.listeners;
   9
  10 import com.google.common.annotations.VisibleForTesting;
  11 import com.google.common.base.Preconditions;
  12 import java.io.StringReader;
  13 import java.time.Instant;
  14 import java.util.Optional;
  15 import javax.xml.XMLConstants;
  16 import javax.xml.parsers.DocumentBuilderFactory;
  17 import javax.xml.parsers.ParserConfigurationException;
  18 import javax.xml.xpath.XPath;
  19 import javax.xml.xpath.XPathConstants;
  20 import javax.xml.xpath.XPathFactory;
  21 import org.opendaylight.restconf.common.errors.RestconfDocumentedException;
  22 import org.w3c.dom.Document;
  23 import org.xml.sax.InputSource;
  24
  25 /**
  26  * Features of query parameters part of both notifications.
  27  *
  28  */
  29 abstract class AbstractQueryParams extends AbstractNotificationsData {
  30     // FIXME: BUG-7956: switch to using UntrustedXML
  31     private static final DocumentBuilderFactory DBF;
  32
  33     static {
  34         final DocumentBuilderFactory f = DocumentBuilderFactory.newInstance();
  35         f.setCoalescing(true);
  36         f.setExpandEntityReferences(false);
  37         f.setIgnoringElementContentWhitespace(true);
  38         f.setIgnoringComments(true);
  39         f.setXIncludeAware(false);
  40         try {
  41             f.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
  42             f.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
  43             f.setFeature("http://xml.org/sax/features/external-general-entities", false);
  44             f.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
  45         } catch (final ParserConfigurationException e) {
  46             throw new ExceptionInInitializerError(e);
  47         }
  48         DBF = f;
  49     }
  50
  51     // FIXME: these should be final
  52     private Instant start = null;
  53     private Instant stop = null;
  54     private String filter = null;
  55     private boolean leafNodesOnly = false;
  56
  57     @VisibleForTesting
  58     public final Instant getStart() {
  59         return start;
  60     }
  61
  62     /**
  63      * Set query parameters for listener.
  64      *
  65      * @param start
  66      *            start-time of getting notification
  67      * @param stop
  68      *            stop-time of getting notification
  69      * @param filter
  70      *            indicate which subset of all possible events are of interest
  71      * @param leafNodesOnly
  72      *            if true, notifications will contain changes to leaf nodes only
  73      */
  74     @SuppressWarnings("checkstyle:hiddenField")
  75     public void setQueryParams(final Instant start, final Optional<Instant> stop, final Optional<String> filter,
  76                                final boolean leafNodesOnly) {
  77         this.start = Preconditions.checkNotNull(start);
  78         this.stop = stop.orElse(null);
  79         this.filter = filter.orElse(null);
  80         this.leafNodesOnly = leafNodesOnly;
  81     }
  82
  83     /**
  84      * Check whether this query should only notify about leaf node changes.
  85      *
  86      * @return true if this query should only notify about leaf node changes
  87      */
  88     public boolean getLeafNodesOnly() {
  89         return leafNodesOnly;
  90     }
  91
  92     @SuppressWarnings("checkstyle:IllegalCatch")
  93     <T extends BaseListenerInterface> boolean checkStartStop(final Instant now, final T listener) {
  94         if (this.stop != null) {
  95             if (this.start.compareTo(now) < 0 && this.stop.compareTo(now) > 0) {
  96                 return true;
  97             }
  98             if (this.stop.compareTo(now) < 0) {
  99                 try {
 100                     listener.close();
 101                 } catch (final Exception e) {
 102                     throw new RestconfDocumentedException("Problem with unregister listener." + e);
 103                 }
 104             }
 105         } else if (this.start != null) {
 106             if (this.start.compareTo(now) < 0) {
 107                 this.start = null;
 108                 return true;
 109             }
 110         } else {
 111             return true;
 112         }
 113         return false;
 114     }
 115
 116     /**
 117      * Check if is filter used and then prepare and post data do client.
 118      *
 119      * @param xml   data of notification
 120      */
 121     @SuppressWarnings("checkstyle:IllegalCatch")
 122     boolean checkFilter(final String xml) {
 123         if (this.filter == null) {
 124             return true;
 125         }
 126
 127         try {
 128             return parseFilterParam(xml);
 129         } catch (final Exception e) {
 130             throw new RestconfDocumentedException("Problem while parsing filter.", e);
 131         }
 132     }
 133
 134     /**
 135      * Parse and evaluate filter value by xml.
 136      *
 137      * @return true or false - depends on filter expression and data of
 138      *         notifiaction
 139      * @throws Exception if operation fails
 140      */
 141     private boolean parseFilterParam(final String xml) throws Exception {
 142         final Document docOfXml = DBF.newDocumentBuilder().parse(new InputSource(new StringReader(xml)));
 143         final XPath xPath = XPathFactory.newInstance().newXPath();
 144         // FIXME: BUG-7956: xPath.setNamespaceContext(nsContext);
 145         return (boolean) xPath.compile(this.filter).evaluate(docOfXml, XPathConstants.BOOLEAN);
 146     }
 147 }