Bug 4883 - implement query parameter - filter

[netconf.git] / restconf / sal-rest-connector / src / main / java / org / opendaylight / netconf / sal / streams / listeners / NotificationListenerAdapter.java

diff --git a/restconf/sal-rest-connector/src/main/java/org/opendaylight/netconf/sal/streams/listeners/NotificationListenerAdapter.java b/restconf/sal-rest-connector/src/main/java/org/opendaylight/netconf/sal/streams/listeners/NotificationListenerAdapter.java
index 303bfb30b5a0519dcce3ebfdb41a903380f35445..1d32b39e23bb077c59120d7bcd5a78c09db0fe35 100644 (file)
--- a/restconf/sal-rest-connector/src/main/java/org/opendaylight/netconf/sal/streams/listeners/NotificationListenerAdapter.java
+++ b/restconf/sal-rest-connector/src/main/java/org/opendaylight/netconf/sal/streams/listeners/NotificationListenerAdapter.java
@@ -18,11 +18,14 @@ import io.netty.util.internal.ConcurrentSet;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStreamWriter;
+import java.io.StringReader;
 import java.io.UnsupportedEncodingException;
 import java.util.Collection;
 import java.util.Date;
 import java.util.Set;
 import java.util.concurrent.Executors;
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.stream.XMLOutputFactory;
 import javax.xml.stream.XMLStreamException;
 import javax.xml.stream.XMLStreamWriter;
@@ -33,6 +36,9 @@ import javax.xml.transform.TransformerFactory;
 import javax.xml.transform.dom.DOMResult;
 import javax.xml.transform.dom.DOMSource;
 import javax.xml.transform.stream.StreamResult;
+import javax.xml.xpath.XPath;
+import javax.xml.xpath.XPathConstants;
+import javax.xml.xpath.XPathFactory;
 import org.json.JSONObject;
 import org.json.XML;
 import org.opendaylight.controller.md.sal.dom.api.DOMNotification;
@@ -56,6 +62,7 @@ import org.slf4j.LoggerFactory;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.w3c.dom.Node;
+import org.xml.sax.InputSource;
 
 /**
  * {@link NotificationListenerAdapter} is responsible to track events on
@@ -77,6 +84,7 @@ public class NotificationListenerAdapter implements DOMNotificationListener {
     private final String outputType;
     private Date start = null;
     private Date stop = null;
+    private String filter;
 
     /**
      * Set path of listener and stream name, register event bus.
@@ -104,7 +112,7 @@ public class NotificationListenerAdapter implements DOMNotificationListener {
         final Date now = new Date();
         if (this.stop != null) {
             if ((this.start.compareTo(now) < 0) && (this.stop.compareTo(now) > 0)) {
-                prepareAndPostData(notification);
+                checkFilter(notification);
             }
             if (this.stop.compareTo(now) < 0) {
                 try {
@@ -116,18 +124,57 @@ public class NotificationListenerAdapter implements DOMNotificationListener {
         } else if (this.start != null) {
             if (this.start.compareTo(now) < 0) {
                 this.start = null;
-                prepareAndPostData(notification);
+                checkFilter(notification);
             }
         } else {
-            prepareAndPostData(notification);
+            checkFilter(notification);
         }
     }
 
     /**
+     * Check if is filter used and then prepare and post data do client
+     *
      * @param notification
+     *            - data of notification
      */
-    private void prepareAndPostData(final DOMNotification notification) {
+    private void checkFilter(final DOMNotification notification) {
         final String xml = prepareXmlFrom(notification);
+        if (this.filter == null) {
+            prepareAndPostData(xml);
+        } else {
+            try {
+                if (parseFilterParam(xml)) {
+                    prepareAndPostData(xml);
+                }
+            } catch (final Exception e) {
+                throw new RestconfDocumentedException("Problem while parsing filter.", e);
+            }
+        }
+    }
+
+    /**
+     * Parse and evaluate filter value by xml
+     *
+     * @param xml
+     *            - notification data in xml
+     * @return true or false - depends on filter expression and data of
+     *         notifiaction
+     * @throws Exception
+     */
+    private boolean parseFilterParam(final String xml) throws Exception {
+        final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
+        final DocumentBuilder builder = factory.newDocumentBuilder();
+        final Document docOfXml = builder.parse(new InputSource(new StringReader(xml)));
+        final XPath xPath = XPathFactory.newInstance().newXPath();
+        return (boolean) xPath.compile(this.filter).evaluate(docOfXml, XPathConstants.BOOLEAN);
+    }
+
+    /**
+     * Prepare data of notification and data to client
+     *
+     * @param xml
+     */
+    private void prepareAndPostData(final String xml) {
         final Event event = new Event(EventType.NOTIFY);
         if (this.outputType.equals("JSON")) {
             final JSONObject jsonObject = XML.toJSONObject(xml);
@@ -423,9 +470,12 @@ public class NotificationListenerAdapter implements DOMNotificationListener {
      *            - start-time of getting notification
      * @param stop
      *            - stop-time of getting notification
+     * @param filter
+     *            - indicate which subset of all possible events are of interest
      */
-    public void setTime(final Date start, final Date stop) {
+    public void setQueryParams(final Date start, final Date stop, final String filter) {
         this.start = start;
         this.stop = stop;
+        this.filter = filter;
     }
 }