// 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 MET08J;

// This noncompliant code example defines a CaseInsensitiveString class that

// includes a String and overrides the equals() method. The CaseInsensitiveString

// class knows about ordinary strings, but the String class has no knowledge of

// case-insensitive strings. Consequently, the CaseInsensitiveString.equals() method

// should not attempt to interoperate with objects of the String class.

final class caseInsensitiveString {

private String s;

private caseInsensitiveString(String s) {

if (s == null) {

throw new NullPointerException();

}

this.s = s;

}

// This method violates symmetry

@Override

public boolean equals(Object o) {

if (o instanceof caseInsensitiveString) {

return s.equalsIgnoreCase(((caseInsensitiveString)o).s);

}

return o instanceof String && s.equalsIgnoreCase((String)o);

}

// Comply with MET09-J

@Override

public int hashCode() {

/* ... */

return 0;

}

public static void main(String[] args) {

caseInsensitiveString cis = new caseInsensitiveString("Java"); //$NON-NLS-1$

String s = "java"; //$NON-NLS-1$

// By operating on String objects, the CaseInsensitiveString.equals() method

// violates the second contract requirement (symmetry). Because of the asymmetry,

// given a String object s and a CaseInsensitiveString object cis that differ

// only in case, cis.equals(s)) returns true, while s.equals(cis) returns false.

System.out.println(cis.equals(s)); // Returns true

System.out.println(s.equals(cis)); // Returns false

}

}