add union(IntList,IntList) and addAll(IntList)

IntPredicate gets the current value and the index.
This was handy while removing duplicate values.

primitiveCollections/src/main/java/org/lucares/collections/IntList.java

@@ -21,7 +21,14 @@ public final class IntList implements Serializable, Cloneable {
 	// TODO add mod counts
 	// TODO support sublists
 	// TODO add lastIndexOf
+	// TODO check that methods like intersection/union work with big arrays. They
+	// should not try to allocate more memory MAX_ARRAY_SIZE
 	// TODO remove bounds checks that are handled by java, e.g. negative indices
+	// TODO removeIf see ArrayList.removeIf. Cannot handle removeIf(i -> indexOf(i)
+	// != lastIndexOf(i)) on sorted lists
+	// TODO wrapper that reverses the order. This implies, that IntList becomes an
+	// interface, or it could not be final anymore. Being an interface would make it
+	// possible to have unmodifiable lists, too.
 
 	private static final long serialVersionUID = 2622570032686034909L;
 
@@ -81,9 +88,8 @@ public final class IntList implements Serializable, Cloneable {
 	 *             if the specified {@link IntList} is null
 	 */
 	public IntList(final IntList intList) {
-		data = Arrays.copyOf(intList.data, intList.size());
-		size = intList.size();
-		sorted = intList.sorted;
+		data = EMPTY_ARRAY;
+		addAll(intList);
 	}
 
 	/**
@@ -261,6 +267,36 @@ public final class IntList implements Serializable, Cloneable {
 		size += values.length;
 	}
 
+	/**
+	 * Add all value of the given list.
+	 *
+	 * @param list
+	 *            the list
+	 * @throws NullPointerException
+	 *             if the given list is null
+	 */
+	public void addAll(final IntList list) {
+		ensureCapacity(list.size());
+
+		System.arraycopy(list.data, 0, data, size, list.size());
+
+		if (sorted) {
+			sorted = list.isSorted();
+			if (list.isSorted() // new list is sorted
+					&& !isEmpty() // if old list is empty, then the new list's sorted value is equal to that of
+									// the new list
+					&& !list.isEmpty()) // if new list is empty, then old list stays sorted
+			{
+				// check that the first new value is bigger than the highest old value
+				final int highestOldValue = data[size - 1]; // size has still the old value
+				final int lowestNewValue = list.get(0);
+				sorted = highestOldValue <= lowestNewValue;
+			}
+		}
+
+		size += list.size();
+	}
+
 	/**
 	 * Removes elements from the list.
 	 * <p>
@@ -344,7 +380,7 @@ public final class IntList implements Serializable, Cloneable {
 		int insertPosition = 0;
 		for (int i = 0; i < size; i++) {
 			final int current = data[i];
-			if (!predicate.test(current)) {
+			if (!predicate.test(current, i)) {
 				// keep current element
 				data[insertPosition] = current;
 				insertPosition++;
@@ -598,8 +634,8 @@ public final class IntList implements Serializable, Cloneable {
 	}
 
 	/**
-	 * Returns the index of the first occurrence of {@code value} starting at the
-	 * {@code offset}'s element, or -1 if it does not exist.
+	 * Returns the index of the last occurrence of {@code value}, or -1 if it does
+	 * not exist.
 	 * <p>
 	 * This method uses a binary search algorithm if the list is sorted.
 	 *
@@ -610,6 +646,8 @@ public final class IntList implements Serializable, Cloneable {
 	 * @return the index, or -1
 	 * @throws ArrayIndexOutOfBoundsException
 	 *             if offset is negative, or larger than the size of the list
+	 * @throws IllegalArgumentException
+	 *             if offset is negative
 	 * @see #isSorted()
 	 */
 	public int indexOf(final int value, final int offset) {
@@ -617,7 +655,7 @@ public final class IntList implements Serializable, Cloneable {
 		int result = -1;
 		if (sorted) {
 			int insertionPoint = Arrays.binarySearch(data, offset, size(), value);
-			while (insertionPoint > 0 && insertionPoint > offset && data[insertionPoint - 1] == value) {
+			while (insertionPoint > offset && data[insertionPoint - 1] == value) {
 				insertionPoint--;
 			}
 			result = insertionPoint < 0 ? -1 : insertionPoint;
@@ -760,12 +798,14 @@ public final class IntList implements Serializable, Cloneable {
 	 * method returns a new list. The list can have unused capacity. Consider using
 	 * {@link #trim()}.
 	 * <p>
+	 * If both lists were sorted, then the output list will also be sorted.
+	 * <p>
 	 * See {@link #retainAll(IntList)} for a method that modifies the list and keeps
 	 * duplicate values.
 	 * <p>
-	 * If both lists are sorted, then the complexity is O(n+m), where n is the
+	 * If both lists are sorted, then the time complexity is O(n+m), where n is the
 	 * length of the first list and m the length of the second list. If at least one
-	 * list is not sorted, then the complexity is O(n*log(m)), where n is the length
+	 * list is not sorted, then the time complexity is O(n*m), where n is the length
 	 * of the shorter list and m the length of the longer list.
 	 *
 	 * @param a
@@ -834,8 +874,8 @@ public final class IntList implements Serializable, Cloneable {
 	}
 
 	/**
-	 * Implements an algorithm with O(n*log(m)), where n is the length of the
-	 * shorter list and m the length of the longer list.
+	 * Implements an algorithm with O(n*m), where n is the length of the shorter
+	 * list and m the length of the longer list.
 	 *
 	 * @param a
 	 *            first list
@@ -851,8 +891,6 @@ public final class IntList implements Serializable, Cloneable {
 		if (aSize < bSize) {
 			result = new IntList(Math.min(aSize, bSize));
 
-			assert !a.isSorted() || !b.isSorted() : "at least one list must be unsorted";
-
 			for (int l = 0; l < aSize; l++) {
 				final int lv = a.get(l);
 
@@ -870,4 +908,104 @@ public final class IntList implements Serializable, Cloneable {
 
 		return result;
 	}
+
+	/**
+	 * Returns a list with all elements that are in list {@code a} or {@code b}
+	 * (logical or).
+	 * <p>
+	 * The result does not contain duplicate values.
+	 * <p>
+	 * If both lists were sorted, then the output list will also be sorted. If at
+	 * least one list is unsorted, then the order is undefined.
+	 * <p>
+	 * If both lists are sorted, then the time complexity is O(n+m), where n is the
+	 * length of the first list and m the length of the second list. If at least one
+	 * list is not sorted, then the time complexity is O((n+m)*log(n+m)), where n is
+	 * the length of the shorter list and m the length of the longer list.
+	 *
+	 * @param a
+	 *            the first list
+	 * @param b
+	 *            the second list
+	 * @return the union of both lists
+	 */
+	public static IntList union(final IntList a, final IntList b) {
+		final IntList result;
+
+		if (a.isSorted() && b.isSorted()) {
+			result = unionSorted(a, b);
+		} else {
+			result = unionUnsorted(a, b);
+		}
+		return result;
+	}
+
+	private static IntList unionSorted(final IntList a, final IntList b) {
+		final IntList result = new IntList(a.size() + b.size());
+
+		final int aSize = a.size();
+		final int bSize = b.size();
+
+		int l = 0;
+		int r = 0;
+
+		while (l < a.size() && r < b.size()) {
+
+			final int lv = a.get(l);
+			final int rv = b.get(r);
+
+			if (lv < rv) {
+				result.add(lv);
+				l++;
+				while (l < aSize && lv == a.get(l)) {
+					l++;
+				}
+			} else if (lv > rv) {
+				result.add(rv);
+				r++;
+				while (r < bSize && rv == b.get(r)) {
+					r++;
+				}
+			} else {
+				result.add(lv);
+				l++;
+				r++;
+
+				while (l < aSize && lv == a.get(l)) {
+					l++;
+				}
+				while (r < bSize && rv == b.get(r)) {
+					r++;
+				}
+			}
+		}
+
+		// add remaining values from list a, if any exist
+		for (; l < aSize; l++) {
+			if (l == 0 || a.get(l) != a.get(l - 1)) {
+				result.add(a.get(l));
+			}
+		}
+
+		// add remaining values from list b, if any exist
+		for (; r < bSize; r++) {
+			if (r == 0 || b.get(r) != b.get(r - 1)) {
+				result.add(b.get(r));
+			}
+		}
+
+		return result;
+	}
+
+	private static IntList unionUnsorted(final IntList a, final IntList b) {
+		// TODO use a more efficient algorithm. Especially the removeIf is too
+		// expensive, because of all the method calls
+		final IntList result;
+		result = new IntList();
+		result.addAll(a);
+		result.addAll(b);
+		result.sort();
+		result.removeIf((value, index) -> index > 0 && result.get(index) == result.get(index - 1));
+		return result;
+	}
 }

primitiveCollections/src/main/java/org/lucares/collections/IntPredicate.java

@@ -11,11 +11,13 @@ public interface IntPredicate {
 	/**
 	 * Evaluates the predicate.
 	 *
-	 * @param i
-	 *            the input argument
+	 * @param value
+	 *            the value
+	 * @param index
+	 *            the index in the list
 	 * @return {@code true} iff the input argument matches the predicate
 	 */
-	boolean test(int i);
+	boolean test(int value, int index);
 
 	/**
 	 * Returns a predicate that represents the logical AND of {@code this} and
@@ -28,7 +30,7 @@ public interface IntPredicate {
 	 *             if {@code other} is null
 	 */
 	default IntPredicate and(final IntPredicate other) {
-		return (t) -> test(t) && other.test(t);
+		return (value, index) -> test(value, index) && other.test(value, index);
 	}
 
 	/**
@@ -42,7 +44,7 @@ public interface IntPredicate {
 	 *             if {@code other} is null
 	 */
 	default IntPredicate or(final IntPredicate other) {
-		return (t) -> test(t) || other.test(t);
+		return (value, index) -> test(value, index) || other.test(value, index);
 	}
 
 	/**
@@ -51,6 +53,6 @@ public interface IntPredicate {
 	 * @return the negation of {@code this}
 	 */
 	default IntPredicate negate() {
-		return (t) -> !test(t);
+		return (value, index) -> !test(value, index);
 	}
 }