// The MIT License (MIT)

//

// Copyright (c) 2017 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 err12j;

import java.io.IOException;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.util.Calendar;

class Whole {

private PartOne p1;

private PartTwo p2;

private Whole(Path path1, Path path2) throws IOException {

this.p1 = new PartOne(path1);

this.p2 = new PartTwo(path2);

}

private Whole(PartOne pone, PartTwo ptwo) {

this.p1 = pone;

this.p2 = ptwo;

}

private PartOne getp1() {

return this.p1;

}

private PartTwo getp2() {

return this.p2;

}

private Whole move(Whole Source) throws IOException {

PartOne t1 = new PartOne(Source.getp1());

if (t1 != null) { // not necessary for copy constructor

try {

PartTwo t2 = new PartTwo(Source.getp2());

if (t2 != null) { // not necessary for copy constructor

try {

// methods that might throw

Calendar rightNow = Calendar.getInstance();

t1.setNow(rightNow);

t2.setNow(rightNow);

// ********************************

// This is the pivotal point of the

// code - everything that could

// fail is before this point.

// Anything that makes persistent

// changes to the state of the

// system is after this point.

// ********************************

// Commit the change to the system state.

// Importantly it won't throw.

// Move

PartOne swap1 = t1;

t1 = p1;

p1 = swap1;

PartTwo swap2 = t2;

t2 = p2;

p2 = swap2;

} finally {

// frees the temporary if we passed the

// pivot uneventfully.

if (t2 != null)

t2.close(); // TODO: catch possible exceptions

}

}

} finally {

// frees the temporary if we passed the

// pivot uneventfully.

if (t1 != null)

t1.close();

}

} // t1 not null

return new Whole(this.p1, this.p2);

} // copy constructor

public static void main(String[] args) {

try {

Whole a = new Whole(Paths.get("p1"), Paths.get("p2"));

System.out.println(a.toString());

Whole b = a.move(a);

System.out.println(b.toString());

}

catch (IOException e) {

e.printStackTrace();

}

finally {

String[] files = { "p1", "p2", "p1copy", "p2copy" };

for (String file : files) {

try {

Files.delete(Paths.get(file));

} catch (IOException e) {

System.err.println("Couldn't delete file " + file);

}

} // end for

} // end finally

} // end main

} // end class Whole

/*

// Move

PartOne swap1 = t1;

t1 = p1;

p1 = swap1;

PartTwo swap2 = t2;

t2 = p2;

p2 = swap2;

*/