#32 StrictXML retries upon network failures

src/main/java/com/jcabi/xml/StrictXML.java

@@ -31,6 +31,7 @@
 
 import com.jcabi.log.Logger;
 import java.io.IOException;
+import java.net.SocketException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Iterator;
@@ -192,19 +193,51 @@ private static String join(final Iterable<?> iterable, final String sep) {
     private static Collection<SAXParseException> validate(final XML xml) {
         final Collection<SAXParseException> errors =
             new CopyOnWriteArrayList<SAXParseException>();
+        final int amountOfRetries = 3;
         try {
-            final Schema schema = SchemaFactory
-                .newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI).newSchema();
-            final Validator validator = schema.newValidator();
+            final Validator validator = newValidator();
             validator.setErrorHandler(
                 new XSDDocument.ValidationHandler(errors)
             );
-            validator.validate(new DOMSource(xml.node()));
+            final DOMSource domsrc = new DOMSource(xml.node());
+            for (int retry = 0; retry < amountOfRetries; ++retry) {
+                try {
+                    validator.validate(domsrc);
+                    // @checkstyle ModifiedControlVariableCheck (1 line)
+                    retry = amountOfRetries;
+                } catch (final SocketException ex) {
+                    Logger.error(
+                        StrictXML.class,
+                        "Try #%d of %d failed: %s: %s",
+                        retry,
+                        amountOfRetries,
+                        ex.getClass().getName(),
+                        ex.getMessage()
+                    );
+                    if (amountOfRetries == retry + 1) {
+                        throw new IllegalStateException(ex);
+                    }
+                }
+            }
         } catch (final SAXException ex) {
             throw new IllegalStateException(ex);
         } catch (final IOException ex) {
             throw new IllegalStateException(ex);
         }
         return errors;
     }
+
+    /**
+     * Creates a new validator.
+     * @return A new validator
+     * @throws SAXException If fails
+     */
+    private static Validator newValidator() throws SAXException {
+        final Schema schema =
+            SchemaFactory
+                .newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI)
+                .newSchema();
+        return schema.newValidator();
+    }
+
 }

src/test/java/com/jcabi/xml/StrictXMLTest.java

@@ -50,21 +50,28 @@
  */
 public final class StrictXMLTest {
 
+    /**
+     * Valid xml document.
+     */
+    private static final String VALID_XML = "<root>test</root>";
+    /**
+     * Xml schema document.
+     */
+    private static final String XSD = StringUtils.join(
+        "<xs:schema xmlns:xs='http://www.w3.org/2001/XMLSchema'>",
+        "<xs:element name='root' type='xs:string'/>",
+        "</xs:schema>"
+    );
+
     /**
      * StrictXML can pass a valid document.
      * @throws Exception If something goes wrong inside
      */
     @Test
     public void passesValidXmlThrough() throws Exception {
         new StrictXML(
-            new XMLDocument("<root>test</root>"),
-            new XSDDocument(
-                StringUtils.join(
-                    "<xs:schema xmlns:xs='http://www.w3.org/2001/XMLSchema'>",
-                    "<xs:element name='root' type='xs:string'/>",
-                    "</xs:schema>"
-                )
-            )
+            new XMLDocument(VALID_XML),
+            new XSDDocument(XSD)
         );
     }
 
@@ -165,4 +172,20 @@ public Void call() throws Exception {
         MatcherAssert.assertThat(done.get(), Matchers.equalTo(Tv.FIFTY));
     }
 
+    /**
+     * Passes valid xml with network problems.
+     * @todo #32 This test does nothing useful for the moment, to be a real test
+     *  it needs to mock com.jcabi.xml.StrictXML.newValidator() and new mocked
+     *  validator should throw few SocketException's while executing
+     *  javax.xml.validation.Validator.validate(Source) in order to simulate the
+     *  situation with network problems. For more details, see
+     *  com.jcabi.xml.StrictXML.validate(XML) as well.
+     */
+    @Test
+    public void passesValidXmlWithNetworkProblems() {
+        new StrictXML(
+            new XMLDocument(VALID_XML), new XSDDocument(XSD)
+        );
+    }
+
 }