[entsoe] Fix XML error handling (#19867)

* sax error handler

Signed-off-by: Bernd Weymann <bernd.weymann@gmail.com>

bundles/org.openhab.binding.entsoe/pom.xml

@@ -3,15 +3,11 @@
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
 
   <modelVersion>4.0.0</modelVersion>
-
   <parent>
     <groupId>org.openhab.addons.bundles</groupId>
     <artifactId>org.openhab.addons.reactor.bundles</artifactId>
     <version>5.2.0-SNAPSHOT</version>
   </parent>
-
   <artifactId>org.openhab.binding.entsoe</artifactId>
-
   <name>openHAB Add-ons :: Bundles :: ENTSO-E Binding</name>
-
 </project>

bundles/org.openhab.binding.entsoe/src/main/java/org/openhab/binding/entsoe/internal/client/EntsoeDocumentParser.java

@@ -36,14 +36,16 @@ import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
+import org.xml.sax.ErrorHandler;
 import org.xml.sax.InputSource;
 import org.xml.sax.SAXException;
+import org.xml.sax.SAXParseException;
 
 /**
  * @author Bernd Weymann - Initial contribution
  */
 @NonNullByDefault
-public class EntsoeDocumentParser {
+public class EntsoeDocumentParser implements ErrorHandler {
     private final DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
     private final Logger logger = LoggerFactory.getLogger(EntsoeDocumentParser.class);
     private final TreeMap<String, String> sequenceDurationMap = new TreeMap<>();
@@ -51,6 +53,10 @@ public class EntsoeDocumentParser {
     private @Nullable String failureReason;
     private @Nullable Document document;
 
+    public EntsoeDocumentParser() {
+        failureReason = "Parser not initialized with response";
+    }
+
     /**
      * Constructor. Parses the given XML response string.
      * Errors during parsing are captured and can be retrieved via {@link #isValid()} and {@link #getFailureReason()}.
@@ -284,6 +290,7 @@ public class EntsoeDocumentParser {
     private @Nullable Document parseDocument(String response)
             throws ParserConfigurationException, SAXException, IOException {
         DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
+        documentBuilder.setErrorHandler(this);
         Document document = documentBuilder.parse(new InputSource(new StringReader(response)));
         document.getDocumentElement().normalize();
         return document;
@@ -301,4 +308,27 @@ public class EntsoeDocumentParser {
         Duration d = Duration.parse(resolution).multipliedBy(iteration);
         return start.plus(d);
     }
+
+    @Override
+    public void warning(@Nullable SAXParseException exception) throws SAXException {
+        throwParserException("Unknown warning", exception);
+    }
+
+    @Override
+    public void error(@Nullable SAXParseException exception) throws SAXException {
+        throwParserException("Unknown error", exception);
+    }
+
+    @Override
+    public void fatalError(@Nullable SAXParseException exception) throws SAXException {
+        throwParserException("Unknown fatal error", exception);
+    }
+
+    private void throwParserException(String message, @Nullable SAXParseException exception) throws SAXException {
+        if (exception != null) {
+            throw exception;
+        } else {
+            throw new SAXException(message);
+        }
+    }
 }

bundles/org.openhab.binding.entsoe/src/main/java/org/openhab/binding/entsoe/internal/handler/EntsoeHandler.java

@@ -67,7 +67,7 @@ public class EntsoeHandler extends BaseThingHandler {
     private final CronScheduler cron;
 
     private EntsoeConfiguration config = new EntsoeConfiguration();
-    private EntsoeDocumentParser parser = new EntsoeDocumentParser("");
+    private EntsoeDocumentParser parser = new EntsoeDocumentParser();
     private TreeMap<Instant, SpotPrice> priceMap = new TreeMap<>();
     private @Nullable ScheduledCompletableFuture<?> cronDaily;
     private @Nullable ScheduledFuture<?> retryJob;

bundles/org.openhab.binding.entsoe/src/test/java/org/openhab/binding/entsoe/TestResponse.java

@@ -232,6 +232,16 @@ public class TestResponse {
         }
     }
 
+    @Test
+    void testEmptyParser() {
+        EntsoeDocumentParser standardParser = new EntsoeDocumentParser();
+        assertNotNull(standardParser);
+        assertNotNull(standardParser.getFailureReason());
+        EntsoeDocumentParser emptyParser = new EntsoeDocumentParser("");
+        assertNotNull(emptyParser);
+        assertNotNull(emptyParser.getFailureReason());
+    }
+
     private void verifySpotPrice(Map<Instant, SpotPrice> map, String timestamp, double expectedValue) {
         SpotPrice testPrice = map.get(Instant.parse(timestamp));
         assertNotNull(testPrice, "No spot price at " + timestamp);