Make 'EqHash' a value-based class

Author: nicolaiparlog

src/main/java/org/codefx/libfx/collection/transform/EqHash.java

@@ -24,7 +24,7 @@ class EqHash<E> {
 	private final BiPredicate<? super E, ? super E> equals;
 	private final ToIntFunction<? super E> hash;
 
-	public EqHash(E element, BiPredicate<? super E, ? super E> equals, ToIntFunction<? super E> hash) {
+	private EqHash(E element, BiPredicate<? super E, ? super E> equals, ToIntFunction<? super E> hash) {
 		// null is allowed as an element
 		assert equals != null : "The argument 'equals' must not be null.";
 		assert hash != null : "The argument 'hash' must not be null.";
@@ -34,6 +34,22 @@ public EqHash(E element, BiPredicate<? super E, ? super E> equals, ToIntFunction
 		this.hash = hash;
 	}
 
+	/**
+	 * @param <E>
+	 *            the type of the wrapped elements
+	 * @param element
+	 *            the wrapped element; may be null
+	 * @param equals
+	 *            the function computing equality of two elements
+	 * @param hash
+	 *            the function computing the hash code of the element
+	 * @return an instance of {@link EqHash}
+	 */
+	public static <E> EqHash<E> create(
+			E element, BiPredicate<? super E, ? super E> equals, ToIntFunction<? super E> hash) {
+		return new EqHash<E>(element, equals, hash);
+	}
+
 	/**
 	 * @return the wrapped element
 	 */
@@ -63,4 +79,8 @@ public boolean equals(Object obj) {
 		return equals.test(this.element, other.element);
 	}
 
+	@Override
+	public String toString() {
+		return "EqHash [" + element + "]";
+	}
 }

src/main/java/org/codefx/libfx/collection/transform/EqualityTransformingMap.java

@@ -104,7 +104,7 @@ protected boolean isOuterKey(Object object) {
 
 	@Override
 	protected EqHash<K> transformToInnerKey(K outerKey) throws ClassCastException {
-		return new EqHash<>(outerKey, equals, hash);
+		return EqHash.create(outerKey, equals, hash);
 	}
 
 	@Override

src/main/java/org/codefx/libfx/collection/transform/EqualityTransformingSet.java

@@ -91,7 +91,7 @@ protected boolean isOuterElement(Object object) {
 
 	@Override
 	protected EqHash<E> transformToInner(E outerElement) throws ClassCastException {
-		return new EqHash<E>(outerElement, equals, hash);
+		return EqHash.create(outerElement, equals, hash);
 	}
 
 }