// The MIT License (MIT)

//

// Copyright (c) 2016 Robert C. Seacord

//

// Permission is hereby granted, free of charge, to any person obtaining a copy

// of this software and associated documentation files (the "Software"), to deal

// in the Software without restriction, including without limitation the rights

// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

// copies of the Software, and to permit persons to whom the Software is

// furnished to do so, subject to the following conditions:

//

// The above copyright notice and this permission notice shall be included in all

// copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

// SOFTWARE.

package EXP03J;

import java.util.Comparator;

class IntegerComparator {

// The == and != operators should not be used to compare boxed primitives.

final private static Comparator<Integer> cmpWrong = (i, j) -> i < j ? -1 : (i == j ? 0 : 1);

// The comparison operators <, >, <=, or >=, cause automatic unboxing

// of primitive values.

final private static Comparator<Integer> cmp = (i, j) -> i < j ? -1 : (i > j ? 1 : 0);

public static void main(String[] args) {

System.out.println("cmpWrong less than: " //$NON-NLS-1$

+ cmpWrong.compare(2147483646, 2147483647));

System.out.println("cmpWrong equal to: " //$NON-NLS-1$

+ cmpWrong.compare(2147483647, 2147483647));

System.out.println("cmpWrong greater than: " //$NON-NLS-1$

+ cmpWrong.compare(2147483647, 2147483646));

System.out.println("cmpWrong equal to with memoized value: " //$NON-NLS-1$

+ cmpWrong.compare(7, 7));

System.out.println("cmp less than: " //$NON-NLS-1$

+ cmp.compare(2147483646, 2147483647));

System.out.println("cmp equal to: " //$NON-NLS-1$

+ cmp.compare(2147483647, 2147483647));

System.out.println("cmp greater than: " //$NON-NLS-1$

+ cmp.compare(2147483647, 2147483646));

// Constructors for class Boolean return distinct objects.

Boolean b1 = new Boolean("true"); //$NON-NLS-1$

Boolean b2 = new Boolean("true"); //$NON-NLS-1$

if (b1 != b2) { // never equal

System.out.println("Never equal"); //$NON-NLS-1$

}

// When comparing a primitive to a boxed value the latter is unboxed.

if (b1 == (boolean)b2) { // always equal

System.out.println("Equal for the same values"); //$NON-NLS-1$

}

b2 = false;

if (b1 == (boolean)b2) { // always

System.out.println("Not equal for different values"); //$NON-NLS-1$

}

// The values of autoboxed Boolean variables may be compared using the

// reference equality operators because Java guarantees that the

// Boolean type is fully memoized.

b1 = true;

b2 = true;

if (b1 == b2) { // always equal

System.out.println("Always equal"); //$NON-NLS-1$

}

b1 = Boolean.TRUE;

if (b1 == b2) { // always equal

System.out.println("Always equal"); //$NON-NLS-1$

}

// The object b is unboxed because the value on the right

// of the == is a primitive type (boolean). So the comparison

// is always comparing the primitive value true with itself.

Boolean b = new Boolean("true"); //$NON-NLS-1$

if (b == true) {

System.out.println("Always equal"); //$NON-NLS-1$

}

}

}