IntMod2.java

/*                        __    __  __  __    __  ___
 *                       \  \  /  /    \  \  /  /  __/
 *                        \  \/  /  /\  \  \/  /  /
 *                         \____/__/  \__\____/__/.ɪᴏ
 * ᶜᵒᵖʸʳᶦᵍʰᵗ ᵇʸ ᵛᵃᵛʳ ⁻ ˡᶦᶜᵉⁿˢᵉᵈ ᵘⁿᵈᵉʳ ᵗʰᵉ ᵃᵖᵃᶜʰᵉ ˡᶦᶜᵉⁿˢᵉ ᵛᵉʳˢᶦᵒⁿ ᵗʷᵒ ᵈᵒᵗ ᶻᵉʳᵒ
 */
package io.vavr.collection;

/**
 * An Int wrapper that implements equality by comparing int values modulo 2.
 * <br>
 * Examples:
 * <ul>
 * <li>IntMod2(0) equals IntMod2(2) equals IntMod2(4) ...</li>
 * <li>IntMod2(1) equals IntMod2(3) equals IntMod2(5) ...</li>
 * <li>IntMod2(0) < IntMod2(1)</li>
 * <li>IntMod2(_even_int_) < IntMod2(_odd_int_)</li>
 * </ul>
 */
final class IntMod2 implements Comparable<IntMod2> {

    private final int val;

    IntMod2(int val) {
        this.val = val;
    }

    @Override
    public int compareTo(IntMod2 that) {
        return this.hashCode() - that.hashCode();
    }

    @Override
    public boolean equals(Object that) {
        return that == this || (that instanceof IntMod2 && this.hashCode() == that.hashCode());
    }

    @Override
    public int hashCode() {
        return val % 2;
    }

    @Override
    public String toString() {
        return String.valueOf(val);
    }

}