GH-4539 remove Iteration interface, remove support for exceptions thr…

…ough generics, change the CloseableIteration interface to implement the Iterator interface.

core/common/iterator/src/main/java/org/eclipse/rdf4j/common/iteration/AbstractCloseableIteration.java

@@ -18,7 +18,7 @@
  * Instances of this class is not safe to be accessed from multiple threads at the same time.
  */
 @Deprecated(since = "4.1.0")
-public abstract class AbstractCloseableIteration<E, X extends Exception> implements CloseableIteration<E, X> {
+public abstract class AbstractCloseableIteration<E> implements CloseableIteration<E> {
 
 	/*-----------*
 	 * Variables *
@@ -46,7 +46,7 @@ public final boolean isClosed() {
 	 * Calls {@link #handleClose()} upon first call and makes sure the resource closures are only executed once.
 	 */
 	@Override
-	public final void close() throws X {
+	public final void close() {
 		if (!closed) {
 			closed = true;
 			handleClose();
@@ -59,6 +59,6 @@ public final void close() throws X {
 	 *
 	 * @throws X
 	 */
-	protected void handleClose() throws X {
+	protected void handleClose() {
 	}
 }

core/common/iterator/src/main/java/org/eclipse/rdf4j/common/iteration/CloseableIteration.java

@@ -11,13 +11,14 @@
 
 package org.eclipse.rdf4j.common.iteration;
 
+import java.util.Iterator;
 import java.util.stream.Stream;
 
 /**
- * An {@link Iteration} that can be closed to free resources that it is holding. CloseableIterations automatically free
- * their resources when exhausted. If not read until exhaustion or if you want to make sure the iteration is properly
- * closed, any code using the iterator should be placed in a try-with-resources block, closing the iteration
- * automatically, e.g.:
+ * An {@link CloseableIteration} that can be closed to free resources that it is holding. CloseableIterations
+ * automatically free their resources when exhausted. If not read until exhaustion or if you want to make sure the
+ * iteration is properly closed, any code using the iterator should be placed in a try-with-resources block, closing the
+ * iteration automatically, e.g.:
  *
  * <pre>
  *
@@ -29,13 +30,13 @@
  * }
  * </pre>
  *
- * @deprecated In the future this interface will stop extending {@link Iteration} and instead declare the same interface
- *             methods directly. The interface will also stop requiring implementations to automatically close when
- *             exhausted, instead making this an optional feature and requiring the user to always call close. This
+ * @deprecated In the future this interface will stop extending {@link CloseableIteration} and instead declare the same
+ *             interface methods directly. The interface will also stop requiring implementations to automatically close
+ *             when exhausted, instead making this an optional feature and requiring the user to always call close. This
  *             interface may also be removed.
  */
 @Deprecated(since = "4.1.0")
-public interface CloseableIteration<E, X extends Exception> extends Iteration<E, X>, AutoCloseable {
+public interface CloseableIteration<E> extends Iterator<E>, AutoCloseable {
 
 	/**
 	 * Convert the results to a Java 8 Stream.
@@ -51,6 +52,6 @@ default Stream<E> stream() {
 	 * invoking this method has no effect.
 	 */
 	@Override
-	void close() throws X;
+	void close();
 
 }

core/common/iterator/src/main/java/org/eclipse/rdf4j/common/iteration/CloseableIterationSpliterator.java

@@ -19,9 +19,9 @@
 /**
  * A {@link Spliterator} implementation that wraps a {@link CloseableIteration}.
  */
-class CloseableIterationSpliterator<T, E extends Exception> extends Spliterators.AbstractSpliterator<T> {
+class CloseableIterationSpliterator<T> extends Spliterators.AbstractSpliterator<T> {
 
-	private final CloseableIteration<T, E> iteration;
+	private final CloseableIteration<T> iteration;
 
 	/**
 	 * Creates a {@link Spliterator} implementation that wraps the supplied {@link CloseableIteration}. It handles
@@ -30,7 +30,7 @@ class CloseableIterationSpliterator<T, E extends Exception> extends Spliterators
 	 *
 	 * @param iteration the iteration to wrap
 	 */
-	public CloseableIterationSpliterator(CloseableIteration<T, E> iteration) {
+	public CloseableIterationSpliterator(CloseableIteration<T> iteration) {
 		super(Long.MAX_VALUE, Spliterator.IMMUTABLE | Spliterator.NONNULL);
 		this.iteration = iteration;
 	}

core/common/iterator/src/main/java/org/eclipse/rdf4j/common/iteration/CloseableIteratorIteration.java

@@ -19,7 +19,7 @@
  * An Iteration that can convert an {@link Iterator} to a {@link CloseableIteration}.
  */
 @Deprecated(since = "4.1.0")
-public class CloseableIteratorIteration<E, X extends Exception> extends AbstractCloseableIteration<E, X> {
+public class CloseableIteratorIteration<E> extends AbstractCloseableIteration<E> {
 
 	private Iterator<? extends E> iter;
 
@@ -46,7 +46,7 @@ protected boolean hasIterator() {
 	}
 
 	@Override
-	public boolean hasNext() throws X {
+	public boolean hasNext() {
 		if (isClosed()) {
 			return false;
 		}
@@ -59,7 +59,7 @@ public boolean hasNext() throws X {
 	}
 
 	@Override
-	public E next() throws X {
+	public E next() {
 		if (isClosed()) {
 			throw new NoSuchElementException("Iteration has been closed");
 		}
@@ -68,7 +68,7 @@ public E next() throws X {
 	}
 
 	@Override
-	public void remove() throws X {
+	public void remove() {
 		if (isClosed()) {
 			throw new IllegalStateException("Iteration has been closed");
 		}

core/common/iterator/src/main/java/org/eclipse/rdf4j/common/iteration/ConvertingIteration.java

@@ -19,7 +19,7 @@
  * over objects of type <var>T</var> (the target type).
  */
 @Deprecated(since = "4.1.0")
-public abstract class ConvertingIteration<S, T, X extends Exception> extends AbstractCloseableIteration<T, X> {
+public abstract class ConvertingIteration<S, T> extends AbstractCloseableIteration<T> {
 
 	/*-----------*
 	 * Variables *
@@ -28,7 +28,7 @@ public abstract class ConvertingIteration<S, T, X extends Exception> extends Abs
 	/**
 	 * The source type iteration.
 	 */
-	private final Iteration<? extends S, ? extends X> iter;
+	private final CloseableIteration<? extends S> iter;
 
 	/*--------------*
 	 * Constructors *
@@ -39,7 +39,7 @@ public abstract class ConvertingIteration<S, T, X extends Exception> extends Abs
 	 *
 	 * @param iter The source type iteration for this <var>ConvertingIteration</var>, must not be <var>null</var>.
 	 */
-	protected ConvertingIteration(Iteration<? extends S, ? extends X> iter) {
+	protected ConvertingIteration(CloseableIteration<? extends S> iter) {
 		this.iter = Objects.requireNonNull(iter, "The iterator was null");
 	}
 
@@ -50,16 +50,16 @@ protected ConvertingIteration(Iteration<? extends S, ? extends X> iter) {
 	/**
 	 * Converts a source type object to a target type object.
 	 */
-	protected abstract T convert(S sourceObject) throws X;
+	protected abstract T convert(S sourceObject);
 
 	/**
 	 * Checks whether the source type iteration contains more elements.
 	 *
 	 * @return <var>true</var> if the source type iteration contains more elements, <var>false</var> otherwise.
-	 * @throws X
+	 *
 	 */
 	@Override
-	public boolean hasNext() throws X {
+	public boolean hasNext() {
 		if (isClosed()) {
 			return false;
 		}
@@ -73,12 +73,12 @@ public boolean hasNext() throws X {
 	/**
 	 * Returns the next element from the source type iteration.
 	 *
-	 * @throws X
+	 *
 	 * @throws java.util.NoSuchElementException If all elements have been returned.
 	 * @throws IllegalStateException            If the iteration has been closed.
 	 */
 	@Override
-	public T next() throws X {
+	public T next() {
 		if (isClosed()) {
 			throw new NoSuchElementException("The iteration has been closed.");
 		}
@@ -94,7 +94,7 @@ public T next() throws X {
 	 *                                       {@link #next}.
 	 */
 	@Override
-	public void remove() throws X {
+	public void remove() {
 		if (isClosed()) {
 			throw new IllegalStateException("The iteration has been closed.");
 		}
@@ -105,11 +105,11 @@ public void remove() throws X {
 	 * Closes this iteration as well as the wrapped iteration if it is a {@link CloseableIteration}.
 	 */
 	@Override
-	protected void handleClose() throws X {
+	protected void handleClose() {
 		try {
 			super.handleClose();
 		} finally {
-			Iterations.closeCloseable(iter);
+			iter.close();
 		}
 	}
 }

core/common/iterator/src/main/java/org/eclipse/rdf4j/common/iteration/DelayedIteration.java

@@ -20,13 +20,13 @@
  * <var>createIteration</var> method, which is called once when the iteration is first needed.
  */
 @Deprecated(since = "4.1.0")
-public abstract class DelayedIteration<E, X extends Exception> extends AbstractCloseableIteration<E, X> {
+public abstract class DelayedIteration<E> extends AbstractCloseableIteration<E> {
 
 	/*-----------*
 	 * Variables *
 	 *-----------*/
 
-	private Iteration<? extends E, ? extends X> iter;
+	private CloseableIteration<? extends E> iter;
 
 	/*--------------*
 	 * Constructors *
@@ -47,17 +47,17 @@ protected DelayedIteration() {
 	 * Creates the iteration that should be iterated over. This method is called only once, when the iteration is first
 	 * needed.
 	 */
-	protected abstract Iteration<? extends E, ? extends X> createIteration() throws X;
+	protected abstract CloseableIteration<? extends E> createIteration();
 
 	/**
 	 * Calls the <var>hasNext</var> method of the underlying iteration.
 	 */
 	@Override
-	public boolean hasNext() throws X {
+	public boolean hasNext() {
 		if (isClosed()) {
 			return false;
 		}
-		Iteration<? extends E, ? extends X> resultIter = iter;
+		CloseableIteration<? extends E> resultIter = iter;
 		if (resultIter == null) {
 			// Underlying iterator has not yet been initialized
 			resultIter = iter;
@@ -73,11 +73,11 @@ public boolean hasNext() throws X {
 	 * Calls the <var>next</var> method of the underlying iteration.
 	 */
 	@Override
-	public E next() throws X {
+	public E next() {
 		if (isClosed()) {
 			throw new NoSuchElementException("Iteration has been closed");
 		}
-		Iteration<? extends E, ? extends X> resultIter = iter;
+		CloseableIteration<? extends E> resultIter = iter;
 		if (resultIter == null) {
 			// Underlying iterator has not yet been initialized
 			resultIter = iter;
@@ -93,11 +93,11 @@ public E next() throws X {
 	 * Calls the <var>remove</var> method of the underlying iteration.
 	 */
 	@Override
-	public void remove() throws X {
+	public void remove() {
 		if (isClosed()) {
 			throw new IllegalStateException("The iteration has been closed.");
 		}
-		Iteration<? extends E, ? extends X> resultIter = iter;
+		CloseableIteration<? extends E> resultIter = iter;
 		if (resultIter == null) {
 			throw new IllegalStateException("Underlying iteration was null");
 		}
@@ -110,13 +110,12 @@ public void remove() throws X {
 	 * {@link CloseableIteration}.
 	 */
 	@Override
-	protected void handleClose() throws X {
+	protected void handleClose() {
 		try {
 			super.handleClose();
 		} finally {
-			Iteration<? extends E, ? extends X> toClose = iter;
-			if (toClose != null) {
-				Iterations.closeCloseable(toClose);
+			if (iter != null) {
+				iter.close();
 			}
 		}
 	}

core/common/iterator/src/main/java/org/eclipse/rdf4j/common/iteration/DistinctIteration.java

@@ -19,7 +19,7 @@
  * An Iteration that filters any duplicate elements from an underlying iterator.
  */
 @Deprecated(since = "4.1.0")
-public class DistinctIteration<E, X extends Exception> extends FilterIteration<E, X> {
+public class DistinctIteration<E> extends FilterIteration<E> {
 
 	/*-----------*
 	 * Variables *
@@ -39,13 +39,13 @@ public class DistinctIteration<E, X extends Exception> extends FilterIteration<E
 	 *
 	 * @param iter The underlying iterator.
 	 */
-	public DistinctIteration(Iteration<? extends E, ? extends X> iter) {
+	public DistinctIteration(CloseableIteration<? extends E> iter) {
 		super(iter);
 
 		excludeSet = makeSet();
 	}
 
-	public DistinctIteration(Iteration<? extends E, ? extends X> iter, Supplier<Set<E>> setMaker) {
+	public DistinctIteration(CloseableIteration<? extends E> iter, Supplier<Set<E>> setMaker) {
 		super(iter);
 		excludeSet = setMaker.get();
 	}
@@ -58,7 +58,7 @@ public DistinctIteration(Iteration<? extends E, ? extends X> iter, Supplier<Set<
 	 * Returns <var>true</var> if the specified object hasn't been seen before.
 	 */
 	@Override
-	protected boolean accept(E object) throws X {
+	protected boolean accept(E object) {
 		if (inExcludeSet(object)) {
 			// object has already been returned
 			return false;
@@ -79,7 +79,7 @@ private boolean inExcludeSet(E object) {
 	/**
 	 * @param object to put into the set
 	 */
-	protected boolean add(E object) throws X {
+	protected boolean add(E object) {
 		return excludeSet.add(object);
 	}