Merge pull request #59 from Adrian-Bielefeldt/26-exception-using-clos…

…ed-reasoner

26 exception using closed reasoner

vlog4j-core/src/main/java/org/semanticweb/vlog4j/core/reasoner/Reasoner.java

@@ -173,8 +173,9 @@ public static Reasoner getInstance() {
 	 *
 	 * @param logLevel
 	 *            the logging level to be set for VLog C++ resource.
+	 * @throws ReasonerStateException if the method is called on a closed reasoner.
 	 */
-	void setLogLevel(@NonNull LogLevel logLevel);
+	void setLogLevel(@NonNull LogLevel logLevel) throws ReasonerStateException;
 
 	/**
 	 * Returns the logging level of the internal VLog C++ resource. If no value has
@@ -194,8 +195,9 @@ public static Reasoner getInstance() {
 	 *            the file for the internal VLog C++ resource to log to. If
 	 *            {@code null} or an invalid file path, the reasoner will log to the
 	 *            default system output.
+	 * @throws ReasonerStateException if the method is called on a closed reasoner.
 	 */
-	void setLogFile(@Nullable String filePath);
+	void setLogFile(@Nullable String filePath) throws ReasonerStateException;
 
 	/**
 	 * Adds rules to the reasoner <b>knowledge base</b> in the given order. After
@@ -322,10 +324,11 @@ void addFactsFromDataSource(@NonNull Predicate predicate, @NonNull DataSource da
 	 *             source ({@link #addFactsFromDataSource(Predicate, DataSource)})
 	 *             does nor match the arity of the facts in the corresponding data
 	 *             source.
+	 * @throws ReasonerStateException if the method is called on a closed reasoner.
 	 */
 	// FIXME should EdbIdbSeparationException be thrown when users try to add
 	// facts/rules?
-	void load() throws IOException, EdbIdbSeparationException, IncompatiblePredicateArityException;
+	void load() throws IOException, EdbIdbSeparationException, IncompatiblePredicateArityException, ReasonerStateException;
 
 	/**
 	 * Performs reasoning on the loaded <b>knowledge base</b>, depending on the set
@@ -358,7 +361,7 @@ void addFactsFromDataSource(@NonNull Predicate predicate, @NonNull DataSource da
 	 * @throws IOException
 	 *             if I/O exceptions occur during reasoning.
 	 * @throws ReasonerStateException
-	 *             if this method is called before loading ({@link Reasoner#load()}.
+	 *             if this method is called before loading ({@link Reasoner#load()} or after closing ({@link Reasoner#close()}).
 	 */
 	boolean reason() throws IOException, ReasonerStateException;
 
@@ -396,7 +399,7 @@ void addFactsFromDataSource(@NonNull Predicate predicate, @NonNull DataSource da
 	 * @return an {@link AutoCloseable} iterator for {@link QueryResult}s,
 	 *         representing distinct answers to the query.
 	 * @throws ReasonerStateException   if this method is called before loading
-	 *                                  ({@link Reasoner#load()}.
+	 *                                  ({@link Reasoner#load()} or after closing ({@link Reasoner#close()}).
 	 * @throws IllegalArgumentException if the given {@code queryAtom} contains
 	 *                                  terms ({@link Atom#getTerms()}) which are
 	 *                                  not of type {@link TermType#CONSTANT} or
@@ -441,7 +444,7 @@ void addFactsFromDataSource(@NonNull Predicate predicate, @NonNull DataSource da
 	 *                      (representing named individuals).
 	 *
 	 * @throws ReasonerStateException   if this method is called before loading
-	 *                                  ({@link Reasoner#load()}.
+	 *                                  ({@link Reasoner#load()} or after closing ({@link Reasoner#close()}).
 	 * @throws IOException              if an I/O error occurs regarding given file
 	 *                                  ({@code csvFilePath)}.
 	 * @throws IllegalArgumentException
@@ -463,8 +466,9 @@ void exportQueryAnswersToCsv(@NonNull Atom queryAtom, @NonNull String csvFilePat
 	 * {@link #load()} method). All facts inferred by reasoning are discarded. Rules
 	 * and facts added to the reasoner need to be loaded again, to be able to
 	 * perform querying and reasoning.
+	 * @throws ReasonerStateException if the method is called on a closed reasoner.
 	 */
-	void resetReasoner();
+	void resetReasoner() throws ReasonerStateException;
 
 	// TODO Map<Predicate,DataSource> exportDBToDir(File location);
 

vlog4j-core/src/main/java/org/semanticweb/vlog4j/core/reasoner/ReasonerState.java

@@ -50,7 +50,15 @@ public enum ReasonerState {
 	 * adding rules, fact and fact data sources and setting the rule re-writing
 	 * strategy are not allowed in this state.
 	 */
-	AFTER_REASONING("completed reasoning");
+	AFTER_REASONING("completed reasoning"),
+	/**
+	 * State a Reasoner is in after method {@link Reasoner#close()} has been called.
+	 * The Reasoner cannot reason again, once it reached this state.
+	 * Loading and setting the reasoning algorithm in this state are ineffective.
+	 * Reasoning, adding rules, fact and fact data sources and setting the rule re-writing
+	 * strategy are not allowed in this state. 
+	 */
+	AFTER_CLOSING("closed");
 
 	private final String name;
 

vlog4j-core/src/main/java/org/semanticweb/vlog4j/core/reasoner/implementation/VLogReasoner.java

@@ -79,6 +79,8 @@ public class VLogReasoner implements Reasoner {
 	public void setAlgorithm(final Algorithm algorithm) {
 		Validate.notNull(algorithm, "Algorithm cannot be null!");
 		this.algorithm = algorithm;
+		if (reasonerState.equals(ReasonerState.AFTER_CLOSING))
+			LOGGER.warn("Setting algorithm on a closed reasoner.");
 	}
 
 	@Override
@@ -92,6 +94,8 @@ public void setReasoningTimeout(Integer seconds) {
 			Validate.isTrue(seconds > 0, "Only strictly positive timeout period alowed!", seconds);
 		}
 		this.timeoutAfterSeconds = seconds;
+		if (reasonerState.equals(ReasonerState.AFTER_CLOSING))
+			LOGGER.warn("Setting timeout on a closed reasoner.");
 	}
 
 	@Override
@@ -112,6 +116,8 @@ public void addRules(final List<Rule> rules) throws ReasonerStateException {
 		}
 		Validate.noNullElements(rules, "Null rules are not alowed! The list contains a null at position [%d].");
 		this.rules.addAll(new ArrayList<>(rules));
+		if (reasonerState.equals(ReasonerState.AFTER_CLOSING))
+			LOGGER.warn("Adding rules to a closed reasoner.");
 	}
 
 	@Override
@@ -122,6 +128,7 @@ public void setRuleRewriteStrategy(RuleRewriteStrategy ruleRewritingStrategy) th
 					"Rules cannot be re-writen after the reasoner has been loaded! Call reset() to undo loading and reasoning.");
 		}
 		this.ruleRewriteStrategy = ruleRewritingStrategy;
+		LOGGER.warn("Setting rule rewrite strategy on a closed reasoner.");
 	}
 
 	@Override
@@ -150,6 +157,8 @@ public void addFacts(final Collection<Atom> facts) throws ReasonerStateException
 			this.factsForPredicate.putIfAbsent(predicate, new HashSet<>());
 			this.factsForPredicate.get(predicate).add(fact);
 		}
+		if (reasonerState.equals(ReasonerState.AFTER_CLOSING))
+			LOGGER.warn("Adding facts to a closed reasoner.");
 	}
 
 	@Override
@@ -167,6 +176,8 @@ public void addFactsFromDataSource(final Predicate predicate, final DataSource d
 				predicate, this.factsForPredicate.get(predicate));
 
 		this.dataSourceForPredicate.put(predicate, dataSource);
+		if (reasonerState.equals(ReasonerState.AFTER_CLOSING))
+			LOGGER.warn("Adding facts to a closed reasoner.");
 	}
 
 	private void validateFactTermsAreConstant(Atom fact) {
@@ -185,7 +196,9 @@ private void validateNoDataSourceForPredicate(final Predicate predicate) {
 	}
 
 	@Override
-	public void load() throws EdbIdbSeparationException, IOException, IncompatiblePredicateArityException {
+	public void load() throws EdbIdbSeparationException, IOException, IncompatiblePredicateArityException, ReasonerStateException {
+		if (reasonerState.equals(ReasonerState.AFTER_CLOSING))
+			throw new ReasonerStateException(reasonerState, "Loading is not allowed after closing.");
 		if (this.reasonerState != ReasonerState.BEFORE_LOADING) {
 			LOGGER.warn("This method call is ineffective: the Reasoner has already been loaded.");
 		} else {
@@ -242,6 +255,8 @@ private void validateDataSourcePredicateArities() throws IncompatiblePredicateAr
 	public boolean reason() throws IOException, ReasonerStateException {
 		if (this.reasonerState == ReasonerState.BEFORE_LOADING) {
 			throw new ReasonerStateException(this.reasonerState, "Reasoning is not allowed before loading!");
+		} else if (reasonerState.equals(ReasonerState.AFTER_CLOSING)) {
+			throw new ReasonerStateException(reasonerState, "Reasoning is not allowed after closing.");
 		} else if (this.reasonerState == ReasonerState.AFTER_REASONING) {
 			LOGGER.warn(
 					"This method call is ineffective: this Reasoner has already reasoned. Successive reason() calls are not supported. Call reset() to undo loading and reasoning and reload to be able to reason again");
@@ -268,6 +283,8 @@ public QueryResultIterator answerQuery(Atom queryAtom, boolean includeBlanks) th
 		final boolean filterBlanks = !includeBlanks;
 		if (this.reasonerState == ReasonerState.BEFORE_LOADING) {
 			throw new ReasonerStateException(this.reasonerState, "Querying is not alowed before reasoner is loaded!");
+		} else if (reasonerState.equals(ReasonerState.AFTER_CLOSING)) {
+			throw new ReasonerStateException(reasonerState, "Querying is not allowed after closing.");
 		}
 		Validate.notNull(queryAtom, "Query atom must not be null!");
 
@@ -287,6 +304,8 @@ public void exportQueryAnswersToCsv(final Atom queryAtom, final String csvFilePa
 		final boolean filterBlanks = !includeBlanks;
 		if (this.reasonerState == ReasonerState.BEFORE_LOADING) {
 			throw new ReasonerStateException(this.reasonerState, "Querying is not alowed before reasoner is loaded!");
+		} else if (reasonerState.equals(ReasonerState.AFTER_CLOSING)) {
+			throw new ReasonerStateException(reasonerState, "Querying is not allowed after closing.");
 		}
 		Validate.notNull(queryAtom, "Query atom must not be null!");
 		Validate.notNull(csvFilePath, "File to export query answer to must not be null!");
@@ -302,7 +321,9 @@ public void exportQueryAnswersToCsv(final Atom queryAtom, final String csvFilePa
 	}
 
 	@Override
-	public void resetReasoner() {
+	public void resetReasoner() throws ReasonerStateException {
+		if (reasonerState.equals(ReasonerState.AFTER_CLOSING))
+			throw new ReasonerStateException(reasonerState, "Resetting is not allowed after closing.");
 		this.reasonerState = ReasonerState.BEFORE_LOADING;
 		this.vLog.stop();
 		LOGGER.warn(
@@ -311,6 +332,7 @@ public void resetReasoner() {
 
 	@Override
 	public void close() {
+		reasonerState = ReasonerState.AFTER_CLOSING;
 		this.vLog.stop();
 	}
 
@@ -382,7 +404,9 @@ private void loadRules() {
 	}
 
 	@Override
-	public void setLogLevel(LogLevel logLevel) {
+	public void setLogLevel(LogLevel logLevel) throws ReasonerStateException {
+		if (reasonerState.equals(ReasonerState.AFTER_CLOSING))
+			throw new ReasonerStateException(reasonerState, "Setting log level is not allowed after closing.");
 		Validate.notNull(logLevel, "Log level cannot be null!");
 		this.internalLogLevel = logLevel;
 		this.vLog.setLogLevel(ModelToVLogConverter.toVLogLogLevel(this.internalLogLevel));
@@ -394,7 +418,9 @@ public LogLevel getLogLevel() {
 	}
 
 	@Override
-	public void setLogFile(String filePath) {
+	public void setLogFile(String filePath) throws ReasonerStateException {
+		if (reasonerState.equals(ReasonerState.AFTER_CLOSING))
+			throw new ReasonerStateException(reasonerState, "Setting log file is not allowed after closing.");
 		this.vLog.setLogFile(filePath);
 	}
 

vlog4j-core/src/test/java/org/semanticweb/vlog4j/core/reasoner/LoggingTest.java

@@ -90,7 +90,7 @@ public void testSetLogFileInexistent() throws ReasonerStateException, IOExceptio
 	}
 
 	@Test(expected = NullPointerException.class)
-	public void testSetLogLevelNull() {
+	public void testSetLogLevelNull() throws ReasonerStateException {
 		try (final Reasoner instance = Reasoner.getInstance()) {
 			instance.setLogLevel(null);
 		}

vlog4j-core/src/test/java/org/semanticweb/vlog4j/core/reasoner/implementation/ReasonerStateTest.java

@@ -123,7 +123,7 @@ public void testAddFacts2() throws EdbIdbSeparationException, IOException, Reaso
 	}
 
 	@Test
-	public void testResetBeforeLoad() {
+	public void testResetBeforeLoad() throws ReasonerStateException {
 		try (final Reasoner reasoner = Reasoner.getInstance()) {
 			reasoner.resetReasoner();
 		}
@@ -286,7 +286,7 @@ public void testFailExportQueryAnswerToCsvBeforeLoad() throws ReasonerStateExcep
 	}
 
 	@Test
-	public void testSuccessiveCloseAfterLoad() throws EdbIdbSeparationException, IOException, IncompatiblePredicateArityException {
+	public void testSuccessiveCloseAfterLoad() throws EdbIdbSeparationException, IOException, IncompatiblePredicateArityException, ReasonerStateException {
 		try (final Reasoner reasoner = Reasoner.getInstance()) {
 			reasoner.load();
 			reasoner.close();

vlog4j-core/src/test/java/org/semanticweb/vlog4j/core/reasoner/implementation/ReasonerTest.java

@@ -46,7 +46,7 @@
 public class ReasonerTest {
 
 	@Test
-	public void testCloseRepeatedly() throws EdbIdbSeparationException, IOException, IncompatiblePredicateArityException {
+	public void testCloseRepeatedly() throws EdbIdbSeparationException, IOException, IncompatiblePredicateArityException, ReasonerStateException {
 		try (final VLogReasoner reasoner = new VLogReasoner()) {
 			reasoner.close();
 		}