// file:    TestCopier.java
// author:  Robert Keller
// purpose: To demonstrate the Copier.maybeClone method.
//          Also, to illustrate cloning and 
//          the distinctions between equals and  ==.

/**
 * ClassC implements cloneable, therefore method clone() is supported.
 */

class ClassC implements Cloneable
{
private static int counter = 0;	// counts number of objects created in class C

String name;			// the name of an object in class C
int serial;			// the serial number of an object in class C


/** Create an object in class C with name x. */

ClassC(String x)
  {
  name = x;
  serial = ++counter;
  }
 

/** Create a new object that is a clone of this. */

public Object clone()
  {
  ClassC cl = new ClassC(name);   // The clone has the same name as original.
  cl.serial = this.serial;	  // The clone even has same serial as original.
  return cl;			  // However, the counter still got incremented.
  }
  

/** Return a String representation of this object. */

public String toString()
  {
  return name + "#" + serial;
  }  


/** Test this object for contents equal to other */

public boolean equals(Object other)
  {
  return toString().equals(other.toString());
  }


/** Return the number of objects constructed in this class. */

static public int getCount()
  {
  return counter;
  }
}


/**
 * ClassD does not implement cloneable, 
 * therefore method clone() is not supported.
 */

class ClassD
{
private static int counter = 0;	// counts number of objects created in class D

String name;			// the name of an object in class D
int serial;			// the serial number of an object in class D


/** Create an object in class D with name x. */

ClassD(String x)
  {
  name = x;
  serial = ++counter;
  }
 

/** Return a String representation of this object. */

public String toString()
  {
  return name + "#" + serial;
  }  


/** Test this object for contents equal to other */

public boolean equals(Object other)
  {
  return toString().equals(other.toString());
  }


/** Return the number of objects constructed in this class. */

static public int getCount()
  {
  return counter;
  }
}


/**
 * TestCopier provides a main method for testing Copier.maybeClone
 */

class TestCopier
{
public static void main(String arg[])
  {
  // Make cloneable object, copy it, and show the result of == and equals tests.

  ClassC c = new ClassC("c");

  System.out.println("Using Copier.maybeClone to copy a cloneable object");

  Object cCopy = Copier.maybeClone(c);

  System.out.println("c = " + c);
  System.out.println("cCopy = " + cCopy);
  System.out.println("c == cCopy      ==> " + (c == cCopy));
  System.out.println("c.equals(cCopy) ==> " + (c.equals(cCopy)));
  System.out.println("As cCopy is a clone of C, " 
                   + "we expect them to be equals but not ==.");
  System.out.println();

  // Make non-cloneable object, copy it, and show the result of == and 
  // equals tests.

  ClassD d = new ClassD("D");

  System.out.println("Using Copier.maybeClone to copy a non-cloneable object");

  Object dCopy = Copier.maybeClone(d);

  System.out.println("d = " + d);
  System.out.println("dCopy = " + dCopy);
  System.out.println("d == dCopy      ==> " + (d == dCopy));
  System.out.println("d.equals(dCopy) ==> " + (d.equals(dCopy)));
  System.out.println("As d is not cloneable, "
                   + "dCopy is just another name for d.");
  System.out.println();

  System.out.println(ClassC.getCount() + " members of ClassC were created.");
  System.out.println(ClassD.getCount() + " members of ClassD were created.");
  }
}

/* Output:

Using Copier.maybeClone to copy a cloneable object
c = c#1
cCopy = c#1
c == cCopy      ==> false
c.equals(cCopy) ==> true
As cCopy is a clone of C, we expect them to be equals but not ==.

Using Copier.maybeClone to copy a non-cloneable object
d = D#1
dCopy = D#1
d == dCopy      ==> true
d.equals(dCopy) ==> true
As d is not cloneable, dCopy is just another name for d.

2 members of ClassC were created.
1 members of ClassD were created.

*/