Fix type of exception thrown if YAMM parser was already closed.

Added a message for this case.

joy-core/src/main/java/org/leadpony/joy/core/AbstractJsonParser.java

@@ -221,6 +221,10 @@ protected final JsonObject getValueAsObject() {
 
     /* provides parsing exceptions */
 
+    protected JsonException newJsonException(String message) {
+        return new JsonException(message);
+    }
+
     protected JsonException newJsonException(String message, Exception e) {
         return new JsonException(message, e);
     }

joy-core/src/main/java/org/leadpony/joy/core/Message.java

@@ -98,6 +98,10 @@ public static String thatIOErrorOccurredWhileParserWasClosing() {
         return format("IOErrorOccurredWhileParserWasClosing");
     }
 
+    public static String thatParserHasBeenAlreadyClosed() {
+        return format("ParserHasBeenAlreadyClosed");
+    }
+
     /*
      * Messages for JSON generator
      */

joy-core/src/main/resources/org/leadpony/joy/core/messages.properties

@@ -36,6 +36,8 @@ NoMoreParserEventsWereFound=No more parser events.
 IOErrorOccurredWhileParserWasReading=An I/O error occurred while the parser was reading.
 IOErrorOccurredWhileParserWasClosing=An I/O error occurred while the parser was closing.
 
+ParserHasBeenAlreadyClosed=The parser has been already closed.
+
 #
 # Messages for JsonGenerator
 #

joy-yaml/src/main/java/org/leadpony/joy/yaml/YamlParser.java

@@ -90,6 +90,8 @@ public Event next() {
             this.nextYamlEvent = null;
             this.eventType = state.processEvent(yamlEvent, this);
             return this.eventType.toJsonEvent();
+        } else if (alreadyClosed) {
+            throw newJsonException(Message.thatParserHasBeenAlreadyClosed());
         } else {
             throw new NoSuchElementException(Message.thatNoMoreParserEventsWereFound());
         }