[unrelated] Add IterableUtil
diff --git a/plugins/org.eclipse.ocl.pivot/src/org/eclipse/ocl/pivot/utilities/IterableUtil.java b/plugins/org.eclipse.ocl.pivot/src/org/eclipse/ocl/pivot/utilities/IterableUtil.java
new file mode 100644
index 0000000..a936360
--- /dev/null
+++ b/plugins/org.eclipse.ocl.pivot/src/org/eclipse/ocl/pivot/utilities/IterableUtil.java
@@ -0,0 +1,101 @@
+/*******************************************************************************
+ * Copyright (c) 2019 Willink Transformations and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v20.html
+ *
+ * Contributors:
+ * E.D.Willink - initial API and implementation
+ * E.D.Willink - Bug 360072
+ *******************************************************************************/
+package org.eclipse.ocl.pivot.utilities;
+
+import java.util.Collection;
+import java.util.Iterator;
+
+import org.eclipse.jdt.annotation.NonNull;
+
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Iterators;
+
+/**
+ * IterableUtil remedies defects in com.google.common.collect.Iterables, in particular the dual Iterables such as addAll.
+ *
+ * @since 1.11
+ */
+public class IterableUtil
+{
+ /**
+ * Adds every element of one iterable to another, returning true if anything added.
+ *
+ * @throws UnsupportedOperationException if addTo does not support add().
+ */
+ public <T> void addAll(@NonNull Iterable<T> addTo, @NonNull Iterable<? extends T> elementsToAdd) {
+ if (elementsToAdd instanceof Collection) {
+ if (addTo instanceof Collection) {
+ ((Collection<T>)addTo).addAll((Collection<? extends T>)elementsToAdd);
+ }
+ else {
+ Iterators.addAll((Collection<T>)addTo, elementsToAdd.iterator());
+ }
+ }
+ else {
+ throw new UnsupportedOperationException();
+ }
+ }
+
+ /**
+ * Removes every element of one iterable from another, returning true if anything removed.
+ *
+ * @throws UnsupportedOperationException if removeFrom does not support remove().
+ */
+ public static boolean removeAll(@NonNull Iterable<?> removeFrom, @NonNull Iterable<?> elementsToRemove) {
+ if (elementsToRemove instanceof Collection) {
+ if (removeFrom instanceof Collection) {
+ return ((Collection<?>)removeFrom).removeAll((Collection<?>)elementsToRemove);
+ }
+ else {
+ return Iterators.removeAll(removeFrom.iterator(), (Collection<?>)elementsToRemove);
+ }
+ }
+ else {
+ Iterator<?> removeFromIterator = removeFrom.iterator();
+ boolean didRemove = false;
+ while (removeFromIterator.hasNext()) {
+ if (Iterables.contains(elementsToRemove, removeFromIterator.next())) {
+ removeFromIterator.remove();
+ didRemove = true;
+ }
+ }
+ return didRemove;
+ }
+ }
+
+ /**
+ * Retain only those elements of one iterable that are present in another, returning true if anything removed.
+ *
+ * @throws UnsupportedOperationException if removeFrom does not support remove().
+ */
+ public static boolean retainAll(@NonNull Iterable<?> removeFrom, @NonNull Iterable<?> elementsToRetain) {
+ if (elementsToRetain instanceof Collection) {
+ if (removeFrom instanceof Collection) {
+ return ((Collection<?>)removeFrom).retainAll((Collection<?>)elementsToRetain);
+ }
+ else {
+ return Iterators.retainAll(removeFrom.iterator(), (Collection<?>)elementsToRetain);
+ }
+ }
+ else {
+ Iterator<?> removeFromIterator = removeFrom.iterator();
+ boolean didRemove = false;
+ while (removeFromIterator.hasNext()) {
+ if (!Iterables.contains(elementsToRetain, removeFromIterator.next())) {
+ removeFromIterator.remove();
+ didRemove = true;
+ }
+ }
+ return didRemove;
+ }
+ }
+}
